Characterization of the catalytic disulfide bond in E. coli 4-thiouridine synthetase to elucidate its functional quaternary structure.

ABSTRACT: 4-Thiouridine at position 8 in prokaryotic tRNA serves as a photosensor for near-UV light, and the posttranscriptional conversion of uridine to 4-thiouridine is catalyzed by the 4-thiouridine synthetases (s(4) US, also named ThiI), which fall into two classes that differ in the presence of a C-terminal rhodanese homology domain. A cysteine residue in this domain first bears a persulfide group and then forms a disulfide bond with a cysteine residue that is conserved in both classes of s(4) US. Recent crystal structures suggest that s(4) US dimerizes in the presence of RNA substrate with domains from each subunit contributing to the binding and reaction of one RNA molecule, which raises the question of whether the catalytic disulfide bond in the longer class of s(4) US is formed within or be

SUBMITTER: Veerareddygari GR 

PROVIDER: S-EPMC5338238 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature