2zpa

Crystal Structure of tRNA(Met) Cytidine Acetyltransferase

spinqualitylabelsall models 2zpa, resolution 2.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2zpa is a 2 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.35Å Ligands: ACO, ADP, MSE, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TMCA_ECOLI Catalyzes the formation of N(4)-acetylcytidine (ac(4)C) at the wobble position of tRNA(Met), by using acetyl-CoA as an acetyl donor and ATP (or GTP). It recognizes the wobble base of tRNA(Met), thus distinguishing between tRNA(Met) and the structurally similar tRNA(Ile2).[HAMAP-Rule:MF_01886] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Post-transcriptional RNA modifications in the anticodon of transfer RNAs frequently contribute to the high fidelity of protein synthesis. In eubacteria, two genome-encoded transfer RNA (tRNA) species bear the same CAU sequence as the anticodons, which are differentiated by modified cytidines at the wobble positions. The elongator tRNA(Met) accepts an acetyl moiety at the wobble base to form N(4)-acetylcytidine (ac(4)C): an inherent modification ensures precise decoding of the AUG codon by strengthening C-G base-pair interaction and concurrently preventing misreading of the near cognate AUA codon. We have determined the crystal structure of tRNA(Met) cytidine acetyltransferase (TmcA) from Escherichia coli complexed with two natural ligands, acetyl-CoA and ADP, at 2.35 A resolution. The structure unexpectedly reveals an idiosyncratic RNA helicase module fused with a GCN5-related N-acetyltransferase (GNAT) fold, which intimately cross-interact. Taken together with the biochemical evidence, we further unravelled the function of acetyl-CoA as an enzyme-activating switch, and propose that an RNA helicase motor driven by ATP hydrolysis is used to deliver the wobble base to the active centre of the GNAT domain. RNA helicase module in an acetyltransferase that modifies a specific tRNA anticodon.,Chimnaronk S, Suzuki T, Manita T, Ikeuchi Y, Yao M, Suzuki T, Tanaka I EMBO J. 2009 May 6;28(9):1362-73. Epub 2009 Mar 26. PMID:19322199 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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