1b5o
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(New page: 200px<br /><applet load="1b5o" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b5o, resolution 2.2Å" /> '''THERMUS THERMOPHILUS ...)
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Revision as of 09:15, 20 November 2007
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THERMUS THERMOPHILUS ASPARTATE AMINOTRANSFERASE SINGLE MUTANT 1
Overview
Aspartate aminotransferase from an extremely thermophilic bacterium, Thermus thermophilus HB8 (ttAspAT), has been believed to be specific for, an acidic substrate. However, stepwise introduction of mutations in the, active-site residues finally changed its substrate specificity to that of, a dual-substrate enzyme. The final mutant, [S15D, T17V, K109S, S292R], ttAspAT, is active toward both acidic and hydrophobic substrates. During, the course of stepwise mutation, the activities toward acidic and, hydrophobic substrates changed independently. The introduction of a mobile, Arg292* residue into ttAspAT was the key step in the change to a, "dual-substrate" enzyme. The substrate recognition mechanism of this, thermostable "dual-substrate" enzyme was confirmed by X-ray, crystallography. This work together with previous studies on various, enzymes suggest that this unique "dual-substrate recognition" mechanism is, a feature of not only aminotransferases but also other enzymes.
About this Structure
1B5O is a Single protein structure of sequence from Thermus thermophilus with PO4 and PLP as ligands. Active as Aspartate transaminase, with EC number 2.6.1.1 Full crystallographic information is available from OCA.
Reference
Substrate recognition mechanism of thermophilic dual-substrate enzyme., Ura H, Nakai T, Kawaguchi SI, Miyahara I, Hirotsu K, Kuramitsu S, J Biochem (Tokyo). 2001 Jul;130(1):89-98. PMID:11432784
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