Crystal structure of a chimaeric bacterial glutamate dehydrogenase
Glutamate dehydrogenases (EC 188.8.131.52–4) catalyse the oxidative deamination of l-glutamate to α-ketoglutarate using NAD(P)+ as a cofactor. The bacterial enzymes are hexameric, arranged with 32 symmetry, and each polypeptide consists of an N-terminal substrate-binding segment (domain I) followed by a C-terminal cofactor-binding segment (domain II). The catalytic reaction takes place in the cleft formed at the junction of the two domains. Distinct signature sequences in the nucleotide-binding domain have been linked to the binding of NAD+ versus NADP+, but they are not unambiguous predictors of cofactor preference. In the absence of substrate, the two domains move apart as rigid bodies, as shown by the apo structure of glutamate dehydrogenase from Clostridium symbiosum. Here, the crystal structure of a chimaeric clostridial/Escherichia coli enzyme has been determined in the apo state. The enzyme is fully functional and reveals possible determinants of interdomain flexibility at a hinge region following the pivot helix. The enzyme retains the preference for NADP+ cofactor from the parent E. coli domain II, although there are subtle differences in catalytic activity.
Contributors : Subhash C Verma ; Sankar Adhya ; Soumya G Remesh ; Michal HammelSeries Type : Expression profiling by high throughput sequencingOrganism : Escherichia coliNucleoid remodeling facilitated by DNA supercoiling results in changes in nucleoid configuration and involves nucleoid-associated proteins (NAPs) and structural maintenance of chromosomes (SMC) proteins among others. Changes in nucleoid configurations regulated by NAPs are synchronized with cellular adaptation and influence the simultaneous expression of several genes. HU, a ubiquitous bacterial histone-like protein, is among the most conserved and abunda...
We report the synthesis and expression measurement of ~9000 inducible promoter variants. By tagging individual variants with barcodes, we can measure the expression levels of all variants under both induced and uninduced conditions in a single pooled experiment. Sequencing data here is used for 1) paired-end sequencing to map barcodes to their promoters or 2) Quantifying the counts of barcodes at the DNA and RNA levels
Contributors : Pabitra Nandy ; Savita Chib ; Aswin S SeshasayeeSeries Type : Expression profiling by high throughput sequencingOrganism : Escherichia coliRNA Sequencing of wild type Eschrichia coli and a RNA polymerase mutant isolated from deep stationary phase
Contributors : Fernando H Martins ; Ashwani Kumar ; Chao Xing ; Vanessa Sperandio ; Waldir P EliasSeries Type : Expression profiling by high throughput sequencingOrganism : Homo sapiensAtypical enteropathogenic Escherichia coli (aEPEC) is amongst the leading causes of diarrheal disease worldwide. The colonization of the gut mucosa by aEPEC results in actin pedestal formation at the site of bacterial attachment. This cytoskeletal rearrangement is triggered by the interaction between the bacterial adhesin intimin and its receptor Tir, which is translocated through the type three secretion system, to the host cell. While some...
Publication date: Available online 30 March 2020Source: Microbial PathogenesisAuthor(s): Jennifer Anne Pienaar, Atheesha Singh, Tobias George Barnard
The Journal of Physical Chemistry BDOI: 10.1021/acs.jpcb.0c01595
ConclusionsThus, hMCs exhibit a highly individualized pattern of immune response possibly to meet tissue requirements and regulate bacteria coexistence vs defense.
Publication date: Available online 30 March 2020Source: Mutation Research/Fundamental and Molecular Mechanisms of MutagenesisAuthor(s): Kristen Fernandez, Sara D’Souza, Jenny J. Ahn, Summer Singh, Erin Mae Bacasen, Daniel Mashiach, Daniel Mishail, Timothy Kao, Jasmine Thai, Spring Hwang, Lekha Yaramada, Jeffrey H. Miller
Publication date: Available online 30 March 2020Source: LWTAuthor(s): David R. Kasler, Taras Pyatkovskyy, Ahmed E. Yousef, Sudhir K. Sastry
The antimicrobial susceptibility testing of 284 Enterobacteriaceae isolates responsible for urinary tract infections to ampicillin, ceftazidime, ciprofloxacin, nitrofurantoin, trimethoprin-sulfamethaxole, and fosfomycin was performed by disk diffusion method. Additionally, in fosfomycin-resistant and intermediate susceptible isolates using disk diffusion method, the minimum inhibitory concentration (MIC) of fosfomycin was determined by agar dilution. The presence of fosA and fosA3 genes and ESBL genes was investigated in fosfomycin-resistant isolates and ESBL-producing isolates, respectively. Klebsiella pneumoniae [72.34% ...