2c5s
From Proteopedia
Crystal structure of Bacillus anthracis ThiI, a tRNA-modifying enzyme containing the predicted RNA-binding THUMP domain
Structural highlights
FunctionTHII_BACAN Catalyzes the ATP-dependent transfer of a sulfur to tRNA to produce 4-thiouridine in position 8 of tRNAs, which functions as a near-UV photosensor. Also catalyzes the transfer of sulfur to the sulfur carrier protein ThiS, forming ThiS-thiocarboxylate. This is a step in the synthesis of thiazole, in the thiamine biosynthesis pathway. The sulfur is donated as persulfide by IscS (By similarity). Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThiI is an enzyme responsible for the formation of the modified base S(4)U (4-thiouridine) found at position 8 in some prokaryotic tRNAs. This base acts as a sensitive trigger for the response mechanism to UV exposure, providing protection against its damaging effects. We present the crystal structure of Bacillus anthracis ThiI in complex with AMP, revealing an extended tripartite architecture in which an N-terminal ferredoxin-like domain (NFLD) connects the C-terminal catalytic PP-loop pyrophosphatase domain with a THUMP domain, an ancient predicted RNA-binding domain that is widespread in all kingdoms of life. We describe the structure of the THUMP domain, which appears to be unrelated to RNA-binding domains of known structure. Mapping the conserved residues of NFLD and the THUMP domain onto the ThiI structure suggests that these domains jointly form the tRNA-binding surface. The inaccessibility of U8 in the canonical L-shaped form of tRNA, and the existence of a glycine-rich linker joining the catalytic and RNA-binding moieties of ThiI suggest that structural changes may occur in both molecules upon binding. Crystal structure of Bacillus anthracis ThiI, a tRNA-modifying enzyme containing the predicted RNA-binding THUMP domain.,Waterman DG, Ortiz-Lombardia M, Fogg MJ, Koonin EV, Antson AA J Mol Biol. 2006 Feb 10;356(1):97-110. Epub 2005 Nov 22. PMID:16343540[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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