2ZPA

Crystal Structure of tRNA(Met) Cytidine Acetyltransferase

Summary for 2ZPA

• Entry DOI: 10.2210/pdb2zpa/pdb
• Descriptor: Uncharacterized protein ypfI, ACETYL COENZYME *A, ADENOSINE-5'-DIPHOSPHATE, ... (5 entities in total)
• Functional Keywords: rna modification enzyme, rna helicase, acetyltransferase, gcn5 acetyltransferase, transferase
• Biological source: Escherichia coli K12
• Cellular location: Cytoplasm (Potential): P76562
• Total number of polymer chains: 2
• Total formula weight: 153138.78

Authors

Chimnaronk, S.,Manita, T.,Yao, M.,Tanaka, I. (deposition date: 2008-07-08, release date: 2009-04-07, Last modification date: 2024-10-23)

Primary citation

Chimnaronk, S.,Suzuki, T.,Manita, T.,Ikeuchi, Y.,Yao, M.,Suzuki, T.,Tanaka, I.
RNA helicase module in an acetyltransferase that modifies a specific tRNA anticodon
Embo J., 28:1362-1373, 2009

PubMed Abstract: 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.

PubMed: 19322199
DOI: 10.1038/emboj.2009.69

Experimental method

X-RAY DIFFRACTION (2.35 Å)