3oei
From Proteopedia
Crystal structure of Mycobacterium tuberculosis RelJK (Rv3357-Rv3358-RelBE3)
Structural highlights
FunctionRELJ_MYCTU Antitoxin component of a toxin-antitoxin (TA) module. A probable antitoxin for the putative mRNA interferase RelK. Upon expression in E.coli but not in M.smegmatis this protein neutralizes E.coli YoeB. Binds to and represses its own promoter, in combination with RelK repression is somewhat lessened. Several DNA-protein complexes are formed in vitro depending on the RelJ:RelK ratio. Publication Abstract from PubMedThe Mycobacterium tuberculosis (Mtb) genome encodes approximately 90 toxin-antitoxin protein complexes, including three RelBE family members, which are believed to play a major role in bacterial fitness and pathogenicity. We have determined the crystal structures of Mtb RelBE-2 and RelBE-3, and the structures reveal homologous heterotetramers. Our structures suggest RelE-2, and by extension the closely related RelE-1, use a different catalytic mechanism than RelE-3, because our analysis of the RelE-2 structure predicts additional amino acid residues that are likely to be functionally significant and are missing from analogous positions in the RelE-3 structure. Toxicity assays corroborate our structural findings; overexpression of RelE-3, whose active site is more similar to Escherichia coli YoeB, has limited consequences on bacterial growth, whereas RelE-1 and RelE-2 overexpression results in acute toxicity. Moreover, RelE-2 overexpression results in an elongated cell phenotype in Mycobacterium smegmatis and protects M. tuberculosis against antibiotics, suggesting a different functional role for RelE-2. Comparative proteomics identifies the cell-associated lethality of M. tuberculosis RelBE-like toxin-antitoxin complexes.,Miallau L, Jain P, Arbing MA, Cascio D, Phan T, Ahn CJ, Chan S, Chernishof I, Maxson M, Chiang J, Jacobs WR Jr, Eisenberg DS Structure. 2013 Apr 2;21(4):627-37. doi: 10.1016/j.str.2013.02.008. Epub 2013 Mar , 21. PMID:23523424[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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