Radical SAM-mediated methylation reactions.

Radical SAM-mediated methylation reactions. Curr Opin Chem Biol. 2013 Jul 5; Authors: Fujimori DG Abstract A subset of enzymes that belong to the radical S-adenosylmethionine (SAM) superfamily is able to catalyze methylation reactions. Substrates of these enzymes are distinct from the nucleophilic substrates that undergo methylation by a polar mechanism. Recently, activities of several radical SAM methylating enzymes have been reconstituted in vitro and their mechanisms of catalysis investigated. The RNA modifying enzymes RlmN and Cfr catalyze methylation via a methyl synthase mechanism. These enzymes use SAM in two distinct roles: as a source of a methyl group transferred to a conserved cysteine and as a source of 5'-deoxyadenosyl radical (5'-dA). Hydrogen atom abstraction by this species generates a thiomethylene radical which adds into the RNA substrate, forming an enzyme-substrate covalent adduct. In another recent study, methylation of the indole moiety of tryptophan by the radical SAM and cobalamin-binding domain enzyme TsrM has been reconstituted. Methylcobalamin serves as an intermediate methyl donor in TsrM, and is proposed to transfer the methyl group as a methyl radical. Interestingly, despite the presence of the radical SAM motif, no reductive cleavage of SAM has been observed in this methylation. These important reconstitutions set the stage for further studies on mechanisms of radical methylation. PMID: 23835516 [PubMed - as supplied by pub...
Source: Current Opinion in Chemical Biology - Category: Biochemistry Authors: Tags: Curr Opin Chem Biol Source Type: research

Related Links:

CONCLUSION: Prevalence of antibiotic use was high not only versus other hospitals in the region but globally including Africa, coupled with significant evidence of sub-optimal prescribing. Swift action is needed to improve future prescribing to reduce AMR. One or two areas should initially be targeted for quality improvement including development of local guidelines, documentation of antibiotic indications and/or stop/review dates. PMID: 33034234 [PubMed - as supplied by publisher]
Source: Expert Review of Anti-Infective Therapy - Category: Infectious Diseases Tags: Expert Rev Anti Infect Ther Source Type: research
Authors: Rombauts A, Abelenda-Alonso G, Cuervo G, Gudiol C, Carratalà J Abstract INTRODUCTION: Despite adequate antibiotic coverage, community-acquired pneumonia (CAP) remains a leading cause of hospitalization and mortality worldwide. It induces both a local pulmonary and a systemic inflammatory response, particularly significant in severe cases. The intensity of the dysregulated host response varies from patient to patient and has a negative impact on survival and other outcomes. AREAS COVERED: This comprehensive review summarizes the pathophysiological aspects of the inflammatory response in CAP, brie...
Source: Expert Review of Anti-Infective Therapy - Category: Infectious Diseases Tags: Expert Rev Anti Infect Ther Source Type: research
Authors: Hammerschlag MR, Sharma R Abstract INTRODUCTION: Azithromycin was recommended as the first-line therapeutic regimen for treatment of genital infections in men and women by the Centers for Disease Control in 1998. A series of studies of azithromycin for treatment of rectal chlamydial infection in men who have sex with men (MSM) found that azithromycin was significantly less effective than doxycycline. AREAS COVERED: Literature on treatment of rectal C. trachomatis from 2000 through May 2020 was searched using PubMed. Retrospective and observational studies were identified documenting the frequency and t...
Source: Expert Review of Anti-Infective Therapy - Category: Infectious Diseases Tags: Expert Rev Anti Infect Ther Source Type: research
Authors: Reissier S, Cattoir V Abstract INTRODUCTION: Streptogramins (pristinamycin and quinupristin-dalfopristin) can be interesting options for the treatment of infections due to Gram-positive cocci, especially multidrug-resistant isolates. AREAS COVERED: This review provides an updated overview on structural and activity characteristics, mechanisms of action and resistance, pharmacokinetic/pharmacodynamic and clinical use of streptogramins. EXPERT OPINION: The streptogramin antibiotics act by inhibition of the bacterial protein synthesis. They are composed of two chemically distinct compounds, namely typ...
Source: Expert Review of Anti-Infective Therapy - Category: Infectious Diseases Tags: Expert Rev Anti Infect Ther Source Type: research
Publication date: 15 February 2021Source: Journal of Hazardous Materials, Volume 404, Part BAuthor(s): Ping He, Yi Zhang, Xinyi Zhao, Jie Wei, Tianhong Xu, Jiang Wu, Naichao Chen
Source: Journal of Hazardous Materials - Category: Environmental Health Source Type: research
Publication date: 15 February 2021Source: Journal of Hazardous Materials, Volume 404, Part BAuthor(s): Jing Li, Haotian Li, Dongdong Lin, Muyi Li, Quansheng Wang, Song Xie, Yuming Zhang, Fengsong Liu
Source: Journal of Hazardous Materials - Category: Environmental Health Source Type: research
Publication date: 15 February 2021Source: Journal of Hazardous Materials, Volume 404, Part BAuthor(s): Yanhua Liu, Yang Li, Shanshan Dong, Lu Han, Ruixin Guo, Yourong Fu, Shenghu Zhang, Jianqiu Chen
Source: Journal of Hazardous Materials - Category: Environmental Health Source Type: research
Publication date: 15 February 2021Source: Journal of Hazardous Materials, Volume 404, Part AAuthor(s): Cheng Han, Yinping Zhang, Marc Redmile-Gordon, Huan Deng, Zhenggui Gu, Qiguo Zhao, Fang Wang
Source: Journal of Hazardous Materials - Category: Environmental Health Source Type: research
Publication date: 15 February 2021Source: Journal of Hazardous Materials, Volume 404, Part AAuthor(s): Taesik Go, Jihwan Kim, Sang Joon Lee
Source: Journal of Hazardous Materials - Category: Environmental Health Source Type: research
Publication date: 15 February 2021Source: Journal of Hazardous Materials, Volume 404, Part AAuthor(s): Daeeun Kwon, Woobin Bae, Jeonghwan Kim
Source: Journal of Hazardous Materials - Category: Environmental Health Source Type: research
More News: Biochemistry | Biology | Chemistry | Study