5ztb
From Proteopedia
Structure of Sulfurtransferase
Structural highlights
Function[TTUB_THET2] Required for the 2-thiolation of 5-methyluridine residue at position 54 in the T loop of tRNAs, leading to 5-methyl-2-thiouridine (m(5)s(2)U or s(2)T) (PubMed:16547008, PubMed:28439027). This modification allows thermal stabilization of tRNAs in thermophilic microorganisms, and is essential for cell growth at high temperatures (PubMed:16547008). Thiocarboxylated TtuB functions as the sulfur donor in the sulfurtransferase reaction catalyzed by TtuA (PubMed:28439027, PubMed:19037260). TtuB also functions as a protein modifier covalently attached to lysine residues of the target proteins TtuA and TtuC (PubMed:22467871). TtuB conjugation might play a regulatory role to ensure appropriate sulfur transfer in cells (PubMed:22467871).[1] [2] [3] [4] [TTUA_THET2] Catalyzes the ATP-dependent 2-thiolation of 5-methyluridine residue at position 54 in the T loop of tRNAs, leading to 5-methyl-2-thiouridine (m(5)s(2)U or s(2)T) (PubMed:16547008, PubMed:28439027). This modification allows thermal stabilization of tRNAs in thermophilic microorganisms, and is required for cell growth at high temperatures (PubMed:16547008). TtuA transfers the S atom from the thiocarboxylated C-terminus of TtuB to tRNA (PubMed:28439027).[5] [6] Publication Abstract from PubMedTtuA and TtuB are the sulfurtransferase and sulfur donor proteins, respectively, for biosynthesis of 2-thioribothymidine (s(2)T) at position 54 of transfer RNA (tRNA), which is responsible for adaptation to high temperature environments in Thermus thermophilus. The enzymatic activity of TtuA requires an iron-sulfur (Fe-S) cluster, by which a sulfur atom supplied by TtuB is transferred to the tRNA substrate. Here, we demonstrate that the Fe-S cluster directly receives sulfur from TtuB through its inherent coordination ability. TtuB forms a [4Fe-4S]-TtuB intermediate, but that sulfur is not immediately released from TtuB. Further desulfurization assays and mutation studies demonstrated that the release of sulfur from the thiocarboxylated C-terminus of TtuB is dependent on adenylation of the substrate tRNA, and the essential residue for TtuB desulfurization was identified. Based on these findings, the molecular mechanism of sulfur transfer from TtuB to Fe-S cluster is proposed. The [4Fe-4S] cluster of sulfurtransferase TtuA desulfurizes TtuB during tRNA modification in Thermus thermophilus.,Chen M, Ishizaka M, Narai S, Horitani M, Shigi N, Yao M, Tanaka Y Commun Biol. 2020 Apr 7;3(1):168. doi: 10.1038/s42003-020-0895-3. PMID:32265486[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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