1riq
From Proteopedia
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The crystal structure of the catalytic fragment of the alanyl-tRNA synthetase
Overview
Early work on aminoacylation of alanine-specific tRNA (tRNA(Ala)) by, alanyl-tRNA synthetase (AlaRS) gave rise to the concept of an early, "second genetic code" imbedded in the acceptor stems of tRNAs. A single, conserved and position-specific G:U base pair in the tRNA acceptor stem is, the key identity determinant. Further understanding has been limited due, to lack of a crystal structure of the enzyme. We determined a 2.14 A, crystal structure of the 453 amino acid catalytic fragment of Aquifex, aeolicus AlaRS. It contains the catalytic domain characteristic of class, II synthetases, a helical domain with a hairpin motif critical for, acceptor-stem recognition, and a C-terminal domain of a mixed alpha/beta, fold. Docking of tRNA(Ala) on AlaRS shows critical contacts with the three, domains, consistent with previous mutagenesis and functional data. It also, suggests conformational flexibility within the C domain, which might allow, for the positional variation of the key G:U base pair seen in some, tRNA(Ala)s.
About this Structure
1RIQ is a Single protein structure of sequence from Aquifex aeolicus. Active as Alanine--tRNA ligase, with EC number 6.1.1.7 Full crystallographic information is available from OCA.
Reference
Alanyl-tRNA synthetase crystal structure and design for acceptor-stem recognition., Swairjo MA, Otero FJ, Yang XL, Lovato MA, Skene RJ, McRee DE, Ribas de Pouplana L, Schimmel P, Mol Cell. 2004 Mar 26;13(6):829-41. PMID:15053876
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