1r6t

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spinqualitylabelsall models 1r6t, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

crystal structure of human tryptophanyl-tRNA synthetase

Contents 1 Overview 2 Disease 3 About this Structure 4 Reference

Overview

Early forms of the genetic code likely generated "statistical" proteins, with similar side chains occupying the same sequence positions at, different ratios. In this scenario, groups of related side chains were, treated by aminoacyl-tRNA synthetases as a single molecular species until, a discrimination mechanism developed that could separate them. The, aromatic amino acids tryptophan, tyrosine, and phenylalanine likely, constituted one of these groups. A crystal structure of human, tryptophanyl-tRNA synthetase was solved at 2.1 A with a, tryptophanyl-adenylate bound at the active site. A cocrystal structure of, an active fragment of human tyrosyl-tRNA synthetase with its cognate amino, acid analog was also solved at 1.6 A. The two structures enabled active, site identifications and provided the information for structure-based, sequence alignments of approximately 45 orthologs of each enzyme. Two, critical positions shared by all tyrosyl-tRNA synthetases and, tryptophanyl-tRNA synthetases for amino acid discrimination were, identified. The variations at these two positions and phylogenetic, analyses based on the structural information suggest that, in contrast to, many other amino acids, discrimination of tyrosine from tryptophan, occurred late in the development of the genetic code.

Disease

Known disease associated with this structure: Wolcott-Rallison syndrome OMIM:[604032]

About this Structure

1R6T is a Single protein structure of sequence from Homo sapiens with TYM and GOL as ligands. Active as Tryptophan--tRNA ligase, with EC number 6.1.1.2 Full crystallographic information is available from OCA.

Reference

Crystal structures that suggest late development of genetic code components for differentiating aromatic side chains., Yang XL, Otero FJ, Skene RJ, McRee DE, Schimmel P, Ribas de Pouplana L, Proc Natl Acad Sci U S A. 2003 Dec 23;100(26):15376-80. Epub 2003 Dec 11. PMID:14671330

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