4elz
From Proteopedia
CCDBVFI:GYRA14VFI
Structural highlights
Function[Q5E5J7_ALIF1] A type II topoisomerase that negatively supercoils closed circular double-stranded (ds) DNA in an ATP-dependent manner to modulate DNA topology and maintain chromosomes in an underwound state. Negative supercoiling favors strand separation, and DNA replication, transcription, recombination and repair, all of which involve strand separation. Also able to catalyze the interconversion of other topological isomers of dsDNA rings, including catenanes and knotted rings. Type II topoisomerases break and join 2 DNA strands simultaneously in an ATP-dependent manner.[HAMAP-Rule:MF_01897] Publication Abstract from PubMedToxin-antitoxin (TA) modules are small operons associated with stress response of bacteria. F-plasmid CcdB(F) was the first TA toxin for which its target, gyrase, was identified. Plasmidic and chromosomal CcdBs belong to distinct families. Conserved residues crucial for gyrase poisoning activity of plasmidic CcdBs are not conserved among these families. Here we show that the chromosomal CcdB(Vfi) from Vibrio fischeri is an active gyrase poison that interacts with its target via an alternative energetic mechanism. Changes in the GyrA14-binding surface of the Vibrio and F-plasmid CcdB family members illustrate neutral drift where alternative interactions can be used to achieve the same functionality. Differences in affinity between V. fischeri and F-plasmid CcdB for gyrase and their corresponding CcdA antitoxin possibly reflect distinct roles for TA modules located on plasmids and chromosomes. Alternative interactions define gyrase specificity in the CcdB family.,De Jonge N, Simic M, Buts L, Haesaerts S, Roelants K, Garcia-Pino A, Sterckx Y, De Greve H, Lah J, Loris R Mol Microbiol. 2012 Jun;84(5):965-978. doi: 10.1111/j.1365-2958.2012.08069.x., Epub 2012 May 14. PMID:22582791[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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