1vfg

Crystal structure of tRNA nucleotidyltransferase complexed with a primer tRNA and an incoming ATP analog

spinqualitylabelsall models 1vfg, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1vfg is a 4 chain structure with sequence from Aquifex aeolicus and Thermotoga maritima. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.8Å Ligands: APC Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT, TOPSAN Function AATNT_AQUAE tRNA nucleotidyltransferase involved in the synthesis of the tRNA CCA terminus. Adds the terminal adenosine residue to tRNA (PubMed:11701927, PubMed:25914059). Can incorporate CMP into tRNA ending with C74C75 (tRNACC), with very weak efficiency (PubMed:25914059). 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 The 3'-terminal CCA nucleotide sequence (positions 74-76) of transfer RNA is essential for amino acid attachment and interaction with the ribosome during protein synthesis. The CCA sequence is synthesized de novo and/or repaired by a template-independent RNA polymerase, 'CCA-adding enzyme', using CTP and ATP as substrates. Despite structural and biochemical studies, the mechanism by which the CCA-adding enzyme synthesizes the defined sequence without a nucleic acid template remains elusive. Here we present the crystal structure of Aquifex aeolicus CCA-adding enzyme, bound to a primer tRNA lacking the terminal adenosine and an incoming ATP analogue, at 2.8 A resolution. The enzyme enfolds the acceptor T helix of the tRNA molecule. In the catalytic pocket, C75 is adjacent to ATP, and their base moieties are stacked. The complementary pocket for recognizing C74-C75 of tRNA forms a 'protein template' for the penultimate two nucleotides, mimicking the nucleotide template used by template-dependent polymerases. These results are supported by systematic analyses of mutants. Our structure represents the 'pre-insertion' stage of selecting the incoming nucleotide and provides the structural basis for the mechanism underlying template-independent RNA polymerization. Structural basis for template-independent RNA polymerization.,Tomita K, Fukai S, Ishitani R, Ueda T, Takeuchi N, Vassylyev DG, Nureki O Nature. 2004 Aug 5;430(7000):700-4. PMID:15295603 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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