Wide ‐open conformation of UDP‐MurNc‐tripeptide ligase revealed by the substrate‐free structure of MurE from Acinetobacter baumannii
In this study, we present the substrate ‐free structure of MurE fromAcinetobacter baumannii, which is an antibiotic ‐resistant superbacterium that has threatened global public health. The structure revealed that MurE has a wide‐open conformation and undergoes wide‐open, intermediately closed, and fully closed dynamic conformational transition. Unveiling structural dynamics of MurE will help to understand th e working mechanism of this ligase and to design next‐generation antibiotics targeting MurE. (Source: FEBS Letters)
Source: FEBS Letters - November 23, 2020 Category: Biochemistry Authors: Kyoung Ho Jung, Yeon ‐Gil Kim, Chang Min Kim, Hyun Ji Ha, Chang Sup Lee, Jun Hyuck Lee, Hyun Ho Park Tags: RESEARCH LETTER Source Type: research

Disruption of small molecule transporter systems by Transporter ‐Interfering Chemicals (TICs)
AbstractSmall molecule transporters (SMTs) in the ABC and SLC families are important players in disposition of diverse endo ‐ and xenobiotics. Interactions of environmental chemicals with these transporters were first postulated in the 1990s, and since validated in numerousin vitro andin vivo scenarios. Recent results on the co ‐crystal structure of ABCB1 with the flame‐retardant BDE‐100 demonstrate that a diverse range of man‐made and natural toxic molecules, hereafter termed Transporter‐Interfering Chemicals (TICs), can directly bind to SMTs and interfere with their function. TIC‐binding modes mimic those o...
Source: FEBS Letters - November 22, 2020 Category: Biochemistry Authors: Sascha C.T. Nicklisch, Amro Hamdoun Tags: PERSPECTIVES Source Type: research

The 14 ‐3‐3/SLP76 protein–protein interaction in T‐cell receptor signalling: a structural and biophysical characterization
The SH2 domain ‐containing protein of 76 kDa, SLP76, is an important adaptor protein that coordinates a complex protein network downstream of T‐cell receptors (TCR), ultimately regulating the immune response. Upon phosphorylation on Ser376, SLP76 interacts with 14‐3‐3 adaptor proteins, which leads to its proteolytic degradation. This provides a negative feedback mechanism by which TCR signalling can be controlled. To gain insight into the 14‐3‐3/SLP76 protein–protein interaction (PPI), we have determined a high‐resolution crystal structure of a SLP76 synthetic peptide containing Ser376 with 14‐3...
Source: FEBS Letters - November 22, 2020 Category: Biochemistry Authors: Lorenzo Soini, Seppe Leysen, Jeremy Davis, Marta Westwood, Christian Ottmann Tags: Research Letter Source Type: research

Munc13 binds and recruits SNAP25 to chaperone SNARE complex assembly
AbstractSynaptic vesicle fusion is mediated by SNARE proteins ‐ VAMP2 on the vesicle and Syntaxin‐1/SNAP25 on the pre‐synaptic membrane. Chaperones Munc18‐1 and Munc13‐1 co‐operatively catalyze SNARE assembly via an intermediate ‘template’ complex containing Syntaxin‐1 and VAMP2. How SNAP25 enters this reaction remains a mystery. Here we repo rt that Munc13‐1 recruits SNAP25 to initiate the ternary SNARE complex assembly by direct binding, as judged by bulk FRET spectroscopy and single‐molecule optical tweezer studies. Detailed structure‐function analyses show that the binding is mediated by...
Source: FEBS Letters - November 22, 2020 Category: Biochemistry Authors: R Venkat Kalyana Sundaram, Huaizhou Jin, Feng Li, Tong Shu, Jeff Coleman, Jie Yang, Frederic Pincet, Yongli Zhang, James E. Rothman, Shyam S. Krishnakumar Tags: RESEARCH ARTICLES Source Type: research

Looking back at multidrug resistance (MDR) research and ten mistakes to be avoided when writing about ABC transporters in MDR
This paper presents a personal, selective, and sometimes critical retrospective of the history of ABC transporters in multidrug resistance (MDR) of cancer cells, overrepresenting discoveries of some early pioneers, long forgotten, and highlights of research in Amsterdam, mainly focussing on discoveries made with disruptions of ABC genes in mice (KO mice) and on the role of ABC transporters in causing drug resistance in a mouse model of mammary cancer. The history is complemented by a list of erroneous concepts often found in papers and grant applications submitted anno 2020. (Source: FEBS Letters)
Source: FEBS Letters - November 21, 2020 Category: Biochemistry Authors: Piet Borst Tags: Review Article Source Type: research

The high ‐resolution X‐ray structure of vinca domain inhibitors of microtubules provides a rational approach for drug design
In this study, we determined the high‐resolution crystal structures of vinorelbine, YXD and Phomopsin A in complex with tubulin at 2.5 Å. Additionally, we recapitulated all previously published high‐resolution crystal structures of the vinca binding site to reveal critical residues and the molecular mechanism of vinca‐do main ligands interacting with tubulin. Furthermore, we designed putatively novel triazolopyrimidine derivatives by introducing secondary amine groups to establish salt‐bridge and H‐bond interactions with Asp179β1 and Asn329α2. Our studies provided the structural basis for designi...
Source: FEBS Letters - November 21, 2020 Category: Biochemistry Authors: Wu Chengyong, Xian Jinghong, Wang Yanyan, Xiao Qing ‐Jie, Ma Lingling, Li Yuyan, Chen Hai, Lei Qian, Zhang Quan, Sun Bo, Wang Yuxi Tags: RESEARCH ARTICLE Source Type: research

The first intracellular loop is essential for the catalytic cycle of the human ABCG2 multidrug resistance transporter
The human multidrug transporter ABCG2 is required for physiological detoxification and mediates anticancer drug resistance. Here, we identify pivotal residues in the first intracellular loop (ICL1), constituting an intrinsic part of the transmission interface. The architecture includes a triple helical bundle formed by the hot spot helix of the nucleotide ‐binding domain, the elbow helix, and ICL1. We show here that the highly conserved ICL1 residues G462, Y463, and Y464 are essential for the proper cross talk of the closed nucleotide‐binding domain dimer with the transmembrane domains. Hence, ICL1 acts as a molecular ...
Source: FEBS Letters - November 21, 2020 Category: Biochemistry Authors: Narakorn Khunweeraphong, Karl Kuchler Tags: Research Letter Source Type: research

From in vitro towards in situ: structure ‐based investigation of ABC exporters by electron paramagnetic resonance spectroscopy
AbstractATP binding cassette (ABC) exporters have been studied now for more than four decades and recent structural investigation has produced a large number of protein database entries. Yet, important questions about how ABC exporters function at the molecular level remain debated, such as which are the molecular recognition hotspots and the allosteric couplings dynamically regulating the communication between the catalytic cycle and the export of substrates. This conundrum mainly arises from technical limitations confining all research toin vitro analysis of ABC transporters in detergent solutions or embedded in membrane...
Source: FEBS Letters - November 20, 2020 Category: Biochemistry Authors: Enrica Bordignon, Markus A. Seeger, Laura Galazzo, Gianmarco Meier Tags: REVIEW Source Type: research

Engineering protein fragments via evolutionary and protein –protein interaction algorithms: de novo design of peptide inhibitors for FOF1‐ATP synthase
Enzyme subunit interfaces have remarkable potential in drug design as both target and scaffold for their own inhibitors. We show an evolution ‐driven strategy for thede  novo design of peptide inhibitors targeting interfaces of theEscherichia  coli FoF1 ‐ATP synthase as a case study. The evolutionary algorithm ROSE was applied to generate diversity‐oriented peptide libraries by engineering peptide fragments from ATP synthase interfaces. The resulting peptides were scored with PPI‐Detect, a sequence‐based predictor of protein–protein inter actions. Two selected peptides were confirmed byin  vi...
Source: FEBS Letters - November 19, 2020 Category: Biochemistry Authors: Yasser B. Ruiz ‐Blanco, Luis Pablo Ávila‐Barrientos, Enrique Hernández‐García, Agostinho Antunes, Guillermin Agüero‐Chapin, Enrique García‐Hernández Tags: Research Article Source Type: research

Lipocalin Blc is a potential heme ‐binding protein
AbstractLipocalins are a superfamily of functionally diverse proteins defined by a well ‐conserved tertiary structure despite variation in sequence. Lipocalins bind and transport small hydrophobic molecules in organisms of all kingdoms. However, there is still uncertainty regarding the function of some members of the family, including bacterial lipocalin Blc fromEscherichia coli. Here, we present evidence that lipocalin Blc may be involved in heme binding, trans ‐periplasmic transport, or heme storage. This conclusion is supported by a co‐crystal structure, mass spectrometric data, absorption titration, andin silico ...
Source: FEBS Letters - November 19, 2020 Category: Biochemistry Authors: Nina G. Bozhanova, M. Wade Calcutt, William N. Beavers, Benjamin P. Brown, Eric P. Skaar, Jens Meiler Tags: RESEARCH ARTICLE Source Type: research

The Human Face of ABCC6
AbstractResearchers working on basic and translational clinical science related to ABC transporters are enthusiastic and dedicated investigators. As the field has grown, so has its contribution to human disease. PXE International, an advocacy organization established by non ‐scientists, began supporting research and convenings on these transporters, specifically ABCC6, the gene associated with pseudoxanthoma elasticum (PXE), 20 years ago. As a patient advocacy organization, we have spent more than 25 years creating a large research consortium, initiating, funding, an d conducting research. Years of basic modelling and vi...
Source: FEBS Letters - November 19, 2020 Category: Biochemistry Authors: Sharon Terry Tags: PERSPECTIVE Source Type: research

Engineering protein fragments via evolutionary and protein –protein interaction algorithms: de novo design of peptide inhibitors for FOF1‐ATP synthase
Enzyme subunit interfaces have remarkable potential in drug design as both target and scaffold for their own inhibitors. We show an evolution ‐driven strategy for thede  novo design of peptide inhibitors targeting interfaces of theEscherichia  coli FoF1 ‐ATP synthase as a case study. The evolutionary algorithm ROSE was applied to generate diversity‐oriented peptide libraries by engineering peptide fragments from ATP synthase interfaces. The resulting peptides were scored with PPI‐Detect, a sequence‐based predictor of protein–protein inter actions. Two selected peptides were confirmed byin  vi...
Source: FEBS Letters - November 19, 2020 Category: Biochemistry Authors: Yasser B. Ruiz ‐Blanco, Luis Pablo Ávila‐Barrientos, Enrique Hernández‐García, Agostinho Antunes, Guillermin Agüero‐Chapin, Enrique García‐Hernández Tags: Research Article Source Type: research

Lipocalin Blc is a potential heme ‐binding protein
AbstractLipocalins are a superfamily of functionally diverse proteins defined by a well ‐conserved tertiary structure despite variation in sequence. Lipocalins bind and transport small hydrophobic molecules in organisms of all kingdoms. However, there is still uncertainty regarding the function of some members of the family, including bacterial lipocalin Blc fromEscherichia coli. Here, we present evidence that lipocalin Blc may be involved in heme binding, trans ‐periplasmic transport, or heme storage. This conclusion is supported by a co‐crystal structure, mass spectrometric data, absorption titration, andin silico ...
Source: FEBS Letters - November 19, 2020 Category: Biochemistry Authors: Nina G. Bozhanova, M. Wade Calcutt, William N. Beavers, Benjamin P. Brown, Eric P. Skaar, Jens Meiler Tags: RESEARCH ARTICLE Source Type: research

The Human Face of ABCC6
AbstractResearchers working on basic and translational clinical science related to ABC transporters are enthusiastic and dedicated investigators. As the field has grown, so has its contribution to human disease. PXE International, an advocacy organization established by non ‐scientists, began supporting research and convenings on these transporters, specifically ABCC6, the gene associated with pseudoxanthoma elasticum (PXE), 20 years ago. As a patient advocacy organization, we have spent more than 25 years creating a large research consortium, initiating, funding, an d conducting research. Years of basic modelling and vi...
Source: FEBS Letters - November 19, 2020 Category: Biochemistry Authors: Sharon Terry Tags: PERSPECTIVE Source Type: research

Negative feedback and modern anti ‐cancer strategies targeting ER stress response
AbstractEndoplasmic reticulum (ER) stress is a cell state in which misfolded or unfolded proteins are aberrantly accumulated in the ER. ER stress induces an evolutionarily conserved adaptive response, named ER stress response, that deploys a self ‐regulated machinery to maintain cellular proteostasis. However, compared to its well‐established canonical activation mechanism, the negative feedback mechanisms regulating the ER stress response remain unclear and no accepted methods or markers have been established. Several studies have docum ented that both endogenous and exogenous insults can induce ER stress in cancer. B...
Source: FEBS Letters - November 18, 2020 Category: Biochemistry Authors: Yaofu Liu, Zhenzhi Tan, Yili Yang Tags: REVIEW Source Type: research

The Ubiquitin Ligase RNF8 Regulates Rho GTPases and Promotes Cytoskeletal Changes and Motility in Triple ‐Negative Breast Cancer Cells
In this study, we investigated the role of RNF8 in regulating Rho GTPases and cell motility. We find that RNF8 knockdown in TNBC ce lls attenuates the protein and mRNA levels of RHOA and CDC42. We show that the formation of filopodia, focal adhesions, and the association of focal adhesions to stress fibers is impaired upon RNF8 knockdown. Cell migration is significantly inhibited by RNF8 knockdown. Our study suggests a potential novel role for RNF8 in mediating cell migration in TNBC through regulation of the Rho GTPases RHOA and CDC42. (Source: FEBS Letters)
Source: FEBS Letters - November 17, 2020 Category: Biochemistry Authors: Bruno Pereira De Carvalho, Yi ‐Jye Chern, Jiabei He, Chia‐Hsin Chan Tags: RESEARCH LETTER Source Type: research

Ligation of 2 ′, 3′‐cyclic phosphate RNAs for the identification of microRNA binding sites
Identifying the targetome of a microRNA is key for understanding its functions. Cross ‐linking and immunoprecipitation (CLIP) methods capture native miRNA‐mRNA interactions in cells. Some of these methods yield small amounts of chimeric miRNA‐mRNA sequencesvia ligation of 5 ′‐phosphorylated RNAs produced during the protocol. Here, we introduce chemically synthesized microRNAs (miRNAs) bearing 2′‐, 3′‐cyclic phosphate groups, as part of a new CLIP method that does not require 5′‐phosphorylation for ligation. We show in a system that models miRNAs bound t o their targets, that addition o...
Source: FEBS Letters - November 16, 2020 Category: Biochemistry Authors: Christian Berk, Yuluan Wang, Artur Laski, Stylianos Tsagkris, Jonathan Hall Tags: Research Letter Source Type: research

An immunomodulatory role for the Mycobacterium tuberculosis Acr protein in the formation of the tuberculous granuloma
AbstractThe tuberculous granuloma is a compact aggregate of dormant bacteria encapsulated by host macrophages. It is commonly regarded as a product of the host ‐defense designed to isolate infectious mycobacteria. This work demonstrates that exposure of macrophages to theMtb heat shock protein Acr leads to overproduction of the chemokine CXCL16, allowing the mycobacterium to exploit the innate immune response. This induction of chemokine expression is hypothesized to occur through activation of ADAM proteases, providing an immunomodulatory role forMtb Acr in the formation of the granuloma. (Source: FEBS Letters)
Source: FEBS Letters - November 13, 2020 Category: Biochemistry Authors: Eamonn F. Healy, Lisa M. Goering, Charles R. Hauser, Peter J. King Tags: HYPOTHESIS Source Type: research

The role of the degenerate nucleotide binding site in type I ABC exporters
AbstractABC transporters are fascinating molecular machines that are capable of transporting a large variety of chemically diverse compounds. The energy required for translocation is derived from binding and hydrolysis of ATP. All ABC transporters share a basic architecture and are composed of two transmembrane domains (TMDs) and two nucleotide binding domains (NBDs). The latter harbor all conserved sequence motifs that hallmark the ABC transporter superfamily. The NBDs form the nucleotide binding sites (NBSs) in their interface. Transporters with two active NBSs are called canonical transporters, while ABC exporters from ...
Source: FEBS Letters - November 12, 2020 Category: Biochemistry Authors: T. Stockner, R. Gradisch, L Schmitt Tags: REVIEW Source Type: research

The Saccharomyces  cerevisiae ABC subfamily D transporter Pxa1/Pxa2p co‐imports CoASH into the peroxisome
ATP ‐binding cassette (ABC) subfamily D transporters are important for the uptake of fatty acids and other beta‐oxidation substrates into peroxisomes. Genetic and biochemical evidence indicates that the transporters accept fatty acyl‐coenzyme A that is cleaved during the transport cycle and then r e‐esterified in the peroxisomal lumen. However, it is not known whether free coenzyme A (CoA) is released inside or outside the peroxisome. Here we have usedSaccharomyces  cerevisiae and isolated peroxisomes to demonstrate that free CoA is released in the peroxisomal lumen. Thus, ABC subfamily D transporter provide a...
Source: FEBS Letters - November 11, 2020 Category: Biochemistry Authors: Carlo W. T. Roermund, Lodewijk IJlst, Alison Baker, Ronald J. A. Wanders, Freddie L. Theodoulou, Hans R. Waterham Tags: Research Article Source Type: research

Front Cover
Cover illustration Cryo ‐ET of reconstituted synaptic fusion. The cover image refers to the article “Arrangements of proteins at reconstituted synaptic vesicle fusion sites depend on membrane separation” by Gingeret al (pp. 3450 –3463). (Source: FEBS Letters)
Source: FEBS Letters - November 10, 2020 Category: Biochemistry Tags: Issue Information Source Type: research

The First Intracellular Loop is Essential for the Catalytic Cycle of Human ABCG2 Multidrug Resistance Transporter
AbstractThe human multidrug transporter ABCG2 is required for physiological detoxification and mediates anticancer drug resistance. Here, we identify pivotal residues in the first intracellular loop (ICL1), constituting an intrinsic part of the transmission interface. The architecture includes a triple helical bundle formed by the hot spot helix of the nucleotide binding domain, the elbow helix and ICL1. We show here that the highly conserved ICL1 residues G462, Y463 and Y464 are essential for the proper crosstalk of the closed NBD dimer with the transmembrane domains. Hence, ICL1 acts as a molecular spring, triggering the...
Source: FEBS Letters - November 9, 2020 Category: Biochemistry Authors: Narakorn Khunweeraphong, Karl Kuchler Tags: RESEARCH LETTER Source Type: research

Structural and functional analyses of the PPIase domain of Arabidopsis  thaliana CYP71 reveal its catalytic activity toward histone H3
Arabidopsis  thaliana CYP71 (AtCYP71) is a chromatin ‐remodeling protein that promotes shoot apical meristem (SAM) differentiation. The N terminus of AtCYP71 contains a noncanonical WD domain, and the C terminus contains an enzymatic peptidyl‐prolyl isomerase (PPIase) cyclophilin (CYP) domain. To date, there has been no characterization of CYP71, and its mode of action remains unknown. Here, we report the crystal structure of the CYP domain of AtCYP71 at 1.9 Å resolution. The structure shows key differences when compared to the canonical CYP fold of human CypA. To the best our knowledge, this is the fir...
Source: FEBS Letters - November 8, 2020 Category: Biochemistry Authors: Smarth Lakhanpal, Jing ‐Song Fan, Sheng Luan, Kunchithapadam Swaminathan Tags: Research Letter Source Type: research

ABRO1 stabilizes the deubiquitinase BRCC3 through inhibiting its degradation mediated by the E3 ubiquitin ligase WWP2
This study provides the first insights into the regulation of BRCC3 stability and expands our knowledge about the phys iological function of WWP2. (Source: FEBS Letters)
Source: FEBS Letters - November 8, 2020 Category: Biochemistry Authors: Wen Zhang, Shou ‐Song Tao, Ting Wang, Jie Zhang, Xian Liu, Ya‐Ting Li, Hui Chen, Yi‐Qun Zhan, Miao Yu, Chang‐Hui Ge, Chang‐Yan Li, Guang‐Ming Ren, Xiao‐Ming Yang, Rong‐Hua Yin Tags: Research Article Source Type: research

Structural and functional analyses of the PPIase domain of Arabidopsis  thaliana CYP71 reveal its catalytic activity toward histone H3
Arabidopsis  thaliana CYP71 (AtCYP71) is a chromatin ‐remodeling protein that promotes shoot apical meristem (SAM) differentiation. The N terminus of AtCYP71 contains a noncanonical WD domain, and the C terminus contains an enzymatic peptidyl‐prolyl isomerase (PPIase) cyclophilin (CYP) domain. To date, there has been no characterization of CYP71, and its mode of action remains unknown. Here, we report the crystal structure of the CYP domain of AtCYP71 at 1.9 Å resolution. The structure shows key differences when compared to the canonical CYP fold of human CypA. To the best our knowledge, this is the fir...
Source: FEBS Letters - November 8, 2020 Category: Biochemistry Authors: Smarth Lakhanpal, Jing ‐Song Fan, Sheng Luan, Kunchithapadam Swaminathan Tags: Research Letter Source Type: research

ABRO1 stabilizes the deubiquitinase BRCC3 through inhibiting its degradation mediated by the E3 ubiquitin ligase WWP2
This study provides the first insights into the regulation of BRCC3 stability and expands our knowledge about the phys iological function of WWP2. (Source: FEBS Letters)
Source: FEBS Letters - November 8, 2020 Category: Biochemistry Authors: Wen Zhang, Shou ‐Song Tao, Ting Wang, Jie Zhang, Xian Liu, Ya‐Ting Li, Hui Chen, Yi‐Qun Zhan, Miao Yu, Chang‐Hui Ge, Chang‐Yan Li, Guang‐Ming Ren, Xiao‐Ming Yang, Rong‐Hua Yin Tags: Research Article Source Type: research

The 14 ‐3‐3/SLP76 protein‐protein interaction in T‐cell receptor signaling: a structural and biophysical characterization
AbstractThe SH2 domain ‐containing protein of 76 kDa, SLP76, is an important adaptor protein that coordinates a complex protein network downstream of T‐cell receptors, ultimately regulating the immune response. Upon phosphorylation on Ser376, SLP76 interacts with 14‐3‐3 adaptor proteins, which leads to its proteol ytic degradation. This provides a negative feedback mechanism by which T‐cell receptor (TCR) signalling can be controlled. To gain insight into the 14‐3‐3/SLP76 protein‐protein interaction (PPI), we have determined a high‐resolution crystal structure of a SLP76 synthetic peptide containing Ser37...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Lorenzo Soini, Seppe Leysen, Jeremy Davis, Marta Westwood, Christian Ottmann Tags: RESEARCH LETTER Source Type: research

Transcription factors and ABC transporters: from pleiotropic drug resistance to cellular signaling in yeast
Budding yeastSaccharomyces  cerevisiae survives in microenvironments utilizing networks of regulators and ATP ‐binding cassette (ABC) transporters to circumvent toxins and a variety of drugs. Our understanding of transcriptional regulation of ABC transporters in yeast is mainly derived from the study of multidrug resistance protein networks. Over the past two decades, this research has not only expanded t he role of transcriptional regulators in pleiotropic drug resistance (PDR) but evolved to include the role that regulators play in cellular signaling and environmental adaptation. Inspection of the gene networks of...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Evan R. Buechel, Heather W. Pinkett Tags: REVIEW ARTICLE Source Type: research

The splicing regulatory factor hnRNPU is a novel transcriptional target of c ‐Myc in hepatocellular carcinoma
Hepatocellular carcinoma (HCC) is the most common liver cancer with high mortality. Here, we found that hnRNPU is overexpressed in HCC tissues and is correlated with the poor prognosis of HCC patients. Besides, hnRNPU is of high significance in regulating the proliferation, apoptosis, self ‐renewal, and tumorigenic potential of HCC cells. Mechanismly, c‐Myc regulates hnRNPU expression at the transcriptional level, and meanwhile, hnRNPU stabilizes the mRNA of c‐MYC. We found that the hnRNPU and c‐Myc regulatory loop exerts a synergistic effect on the proliferation and self‐re newal of HCC, and promotes the HCC pro...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Biao Zhang, Hai ‐Yang Wang, De‐Xi Zhao, Dong‐Xing Wang, Quan Zeng, Jia‐Fei Xi, Xue Nan, Li‐Juan He, Jun‐Nian Zhou, Xue‐Tao Pei, Wen Yue Tags: Research Article Source Type: research

Occludin ‐binding single‐chain variable fragment and antigen‐binding fragment antibodies prevent hepatitis C virus infection
In this study, we converted these mAbs to corresponding monovalent antigen ‐binding fragments (Fabs) and single‐chain variable fragment (scFv) antibodies. These Fab fragments and scFv antibodies demonstrate similar binding specificity and affinity to parental anti‐OCLN mAbs. Moreover, Fab fragments and scFv antibodies inhibitin  vitro HCV infection. The small functional monovalent OCLN ‐binding probes reported in our study have high potential as drug candidates and tools for biological and pharmaceutical studies of OCLN. (Source: FEBS Letters)
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Yoshimi Shimizu, Takehiro Shinoda, Yoshitaka Shirasago, Masuo Kondoh, Naoko Shinya, Kentaro Hanada, Kiyohito Yagi, Tetsuro Suzuki, Takaji Wakita, Tomomi Kimura ‐Someya, Mikako Shirouzu, Masayoshi Fukasawa Tags: Research Article Source Type: research

Creation of the first monoclonal antibody recognizing an extracellular epitope of hABCC6
AbstractMutations in theABCC6 gene result in calcification diseases such as pseudoxanthoma elasticum or Generalized Arterial Calcification of Infancy. Generation of antibodies recognizing an extracellular epitope of ABCC6 has been hampered by the short extracellular segments of the protein. To overcome this limitation, we immunized Bovine FcRn transgenic mice exhibiting an augmented humoral immune response with HEK cells expressing human ABCC6 (hABCC6). We obtained a monoclonal antibody recognizing an extracellular epitope of hABCC6 that we named mEChC6. Limited proteolysis revealed that the epitope is within a loop in the...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: E. Koz ák, B. Szikora, A. Iliás, P.K. Jani, Z. Hegyi, Zs. Matula, D. Dedinszki, N. Tőkési, K. Fülöp, V. Pomozi, Gy. Várady, É. Bakos, G.E. Tusnády, I. Kacskovics, A. Váradi Tags: RESEARCH LETTER Source Type: research

Conformational changes of the nucleotide binding domains of P ‐glycoprotein induced by ATP hydrolysis
AbstractP ‐glycoprotein (Pgp) is a member of the ABC transporter superfamily with high physiological importance. Pgp nucleotide binding domains (NBDs) drive the transport cycle through ATP binding and hydrolysis. We use molecular dynamics simulations to investigate the ATP hydrolysis‐induced conformationa l changes of NBDs. Five systems, including all possible ATP/ADP combinations in the NBDs and the APO system, are simulated. ATP/ADP exchange induces conformational changes mostly within the conserved signature motif of the NBDs, resulting in relative orientational changes of the NBDs. Nucleotide rem oval leads to addi...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Sepehr Dehghani ‐Ghahnaviyeh, Karan Kapoor, Emad Tajkhorshid Tags: RESEARCH ARTICLE Source Type: research

Mitochondrial disorders of the oxphos system
AbstractMitochondrial disorders are amongst the most frequent inborn errors of metabolism, their primary cause being the dysfunction of the oxidative phosphorylation system (OXPHOS). OXPHOS is composed of the electron transport chain (ETC), formed by four multimeric enzymes and two mobile electron carriers, plus an ATP synthase (also called complex V). The ETC performs the redox reactions involved in cellular respiration while generating the proton motive force used by complex V to synthesize ATP. OXPHOS biogenesis involves multiple steps, starting from the expression of genes encoded in physically separated genomes, namel...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Erika Fernandez ‐Vizarra, Massimo Zeviani Tags: REVIEW Source Type: research

Structural changes induced by ligand ‐binding drastically increase the thermostability of the Ser/Thr protein kinase TpkD from Thermus thermophilus HB8
AbstractThermophilic proteins maintain their structure at high temperatures through a combination of various factors.  Here, we report the ligand‐induced stabilization of a thermophilic Ser/Thr protein kinase.  Thermus thermophilus TpkD unfolds completely at 55°C despite the optimum growth temperature of 75°C. Unexpectedly, we found that the TpkD structure is drastically stabilized by its natural ligands ATP and ADP, as evidenced by the increase in the melting temperature to 80°C. Such a striking effect of a substra te on thermostability has not been...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Yusuke Fujino, Takero Miyagawa, Masayuki Torii, Masao Inoue, Yuki Fujii, Hiroki Okanishi, Yoshikatsu Kanai, Ryoji Masui Tags: RESEARCH LETTER Source Type: research

Transcription factors and ABC transporters: from pleiotropic drug resistance to cellular signaling in yeast
Budding yeastSaccharomyces  cerevisiae survives in microenvironments utilizing networks of regulators and ATP ‐binding cassette (ABC) transporters to circumvent toxins and a variety of drugs. Our understanding of transcriptional regulation of ABC transporters in yeast is mainly derived from the study of multidrug resistance protein networks. Over the past two decades, this research has not only expanded t he role of transcriptional regulators in pleiotropic drug resistance (PDR) but evolved to include the role that regulators play in cellular signaling and environmental adaptation. Inspection of the gene networks of...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Evan R. Buechel, Heather W. Pinkett Tags: REVIEW ARTICLE Source Type: research

The splicing regulatory factor hnRNPU is a novel transcriptional target of c ‐Myc in hepatocellular carcinoma
Hepatocellular carcinoma (HCC) is the most common liver cancer with high mortality. Here, we found that hnRNPU is overexpressed in HCC tissues and is correlated with the poor prognosis of HCC patients. Besides, hnRNPU is of high significance in regulating the proliferation, apoptosis, self ‐renewal, and tumorigenic potential of HCC cells. Mechanismly, c‐Myc regulates hnRNPU expression at the transcriptional level, and meanwhile, hnRNPU stabilizes the mRNA of c‐MYC. We found that the hnRNPU and c‐Myc regulatory loop exerts a synergistic effect on the proliferation and self‐re newal of HCC, and promotes the HCC pro...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Biao Zhang, Hai ‐Yang Wang, De‐Xi Zhao, Dong‐Xing Wang, Quan Zeng, Jia‐Fei Xi, Xue Nan, Li‐Juan He, Jun‐Nian Zhou, Xue‐Tao Pei, Wen Yue Tags: Research Article Source Type: research

Occludin ‐binding single‐chain variable fragment and antigen‐binding fragment antibodies prevent hepatitis C virus infection
In this study, we converted these mAbs to corresponding monovalent antigen ‐binding fragments (Fabs) and single‐chain variable fragment (scFv) antibodies. These Fab fragments and scFv antibodies demonstrate similar binding specificity and affinity to parental anti‐OCLN mAbs. Moreover, Fab fragments and scFv antibodies inhibitin  vitro HCV infection. The small functional monovalent OCLN ‐binding probes reported in our study have high potential as drug candidates and tools for biological and pharmaceutical studies of OCLN. (Source: FEBS Letters)
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Yoshimi Shimizu, Takehiro Shinoda, Yoshitaka Shirasago, Masuo Kondoh, Naoko Shinya, Kentaro Hanada, Kiyohito Yagi, Tetsuro Suzuki, Takaji Wakita, Tomomi Kimura ‐Someya, Mikako Shirouzu, Masayoshi Fukasawa Tags: Research Article Source Type: research

Creation of the first monoclonal antibody recognizing an extracellular epitope of hABCC6
AbstractMutations in theABCC6 gene result in calcification diseases such as pseudoxanthoma elasticum or Generalized Arterial Calcification of Infancy. Generation of antibodies recognizing an extracellular epitope of ABCC6 has been hampered by the short extracellular segments of the protein. To overcome this limitation, we immunized Bovine FcRn transgenic mice exhibiting an augmented humoral immune response with HEK cells expressing human ABCC6 (hABCC6). We obtained a monoclonal antibody recognizing an extracellular epitope of hABCC6 that we named mEChC6. Limited proteolysis revealed that the epitope is within a loop in the...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: E. Koz ák, B. Szikora, A. Iliás, P.K. Jani, Z. Hegyi, Zs. Matula, D. Dedinszki, N. Tőkési, K. Fülöp, V. Pomozi, Gy. Várady, É. Bakos, G.E. Tusnády, I. Kacskovics, A. Váradi Tags: RESEARCH LETTER Source Type: research

The 14 ‐3‐3/SLP76 protein‐protein interaction in T‐cell receptor signaling: a structural and biophysical characterization
AbstractThe SH2 domain ‐containing protein of 76 kDa, SLP76, is an important adaptor protein that coordinates a complex protein network downstream of T‐cell receptors, ultimately regulating the immune response. Upon phosphorylation on Ser376, SLP76 interacts with 14‐3‐3 adaptor proteins, which leads to its proteol ytic degradation. This provides a negative feedback mechanism by which T‐cell receptor (TCR) signalling can be controlled. To gain insight into the 14‐3‐3/SLP76 protein‐protein interaction (PPI), we have determined a high‐resolution crystal structure of a SLP76 synthetic peptide containing Ser37...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Lorenzo Soini, Seppe Leysen, Jeremy Davis, Marta Westwood, Christian Ottmann Tags: RESEARCH LETTER Source Type: research

Conformational changes of the nucleotide binding domains of P ‐glycoprotein induced by ATP hydrolysis
AbstractP ‐glycoprotein (Pgp) is a member of the ABC transporter superfamily with high physiological importance. Pgp nucleotide binding domains (NBDs) drive the transport cycle through ATP binding and hydrolysis. We use molecular dynamics simulations to investigate the ATP hydrolysis‐induced conformationa l changes of NBDs. Five systems, including all possible ATP/ADP combinations in the NBDs and the APO system, are simulated. ATP/ADP exchange induces conformational changes mostly within the conserved signature motif of the NBDs, resulting in relative orientational changes of the NBDs. Nucleotide rem oval leads to addi...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Sepehr Dehghani ‐Ghahnaviyeh, Karan Kapoor, Emad Tajkhorshid Tags: RESEARCH ARTICLE Source Type: research

Mitochondrial disorders of the oxphos system
AbstractMitochondrial disorders are amongst the most frequent inborn errors of metabolism, their primary cause being the dysfunction of the oxidative phosphorylation system (OXPHOS). OXPHOS is composed of the electron transport chain (ETC), formed by four multimeric enzymes and two mobile electron carriers, plus an ATP synthase (also called complex V). The ETC performs the redox reactions involved in cellular respiration while generating the proton motive force used by complex V to synthesize ATP. OXPHOS biogenesis involves multiple steps, starting from the expression of genes encoded in physically separated genomes, namel...
Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Erika Fernandez ‐Vizarra, Massimo Zeviani Tags: REVIEW Source Type: research