1asz
From Proteopedia
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THE ACTIVE SITE OF YEAST ASPARTYL-TRNA SYNTHETASE: STRUCTURAL AND FUNCTIONAL ASPECTS OF THE AMINOACYLATION REACTION
Overview
The crystal structures of the various complexes formed by yeast, aspartyl-tRNA synthetase (AspRS) and its substrates provide snapshots of, the active site corresponding to different steps of the aminoacylation, reaction. Native crystals of the binary complex tRNA-AspRS were soaked in, solutions containing the two other substrates, ATP (or its analog AMPPcP), and aspartic acid. When all substrates are present in the crystal, this, leads to the formation of the aspartyl-adenylate and/or the aspartyl-tRNA., A class II-specific pathway for the aminoacylation reaction is proposed, which explains the known functional differences between the two classes, while preserving a common framework. Extended signature sequences, characteristic of class II aaRS (motifs 2 and 3) constitute the basic, functional unit. The ATP molecule adopts a bent conformation, stabilized, by the invariant Arg531 of motif 3 and a magnesium ion coordinated to the, pyrophosphate group and to two class-invariant acidic residues. The, aspartic acid substrate is positioned by a class II invariant acidic, residue, Asp342, interacting with the amino group and by amino acids, conserved in the aspartyl synthetase family. The amino acids in contact, with the substrates have been probed by site-directed mutagenesis for, their functional implication.
About this Structure
1ASZ is a Single protein structure of sequence from Saccharomyces cerevisiae with ATP as ligand. The following page contains interesting information on the relation of 1ASZ with [Aminoacyl-tRNA Synthetases]. Active as Aspartate--tRNA ligase, with EC number 6.1.1.12 Full crystallographic information is available from OCA.
Reference
The active site of yeast aspartyl-tRNA synthetase: structural and functional aspects of the aminoacylation reaction., Cavarelli J, Eriani G, Rees B, Ruff M, Boeglin M, Mitschler A, Martin F, Gangloff J, Thierry JC, Moras D, EMBO J. 1994 Jan 15;13(2):327-37. PMID:8313877
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