2v03
From Proteopedia
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HIGH RESOLUTION STRUCTURE AND CATALYSIS OF AN O-ACETYLSERINE SULFHYDRYLASE
Overview
The crystal structure of the dimeric O-acetylserine sulfhydrylase isozyme B from Escherichia coli (CysM), complexed with the substrate analog citrate, has been determined at 1.33 A resolution by X-ray diffraction analysis. The C1-carboxylate of citrate was bound at the carboxylate position of O-acetylserine, whereas the C6-carboxylate adopted two conformations. The activity of the enzyme and of several active center mutants was determined using an assay based on O-acetylserine and thio-nitrobenzoate (TNB). The unnatural substrate TNB was modeled into the reported structure. The substrate model and the observed mutant activities may facilitate future protein engineering attempts designed to broaden the substrate spectrum of the enzyme. A comparison of the reported structure with previously published CysM structures revealed large conformational changes. One of the crystal forms contained two dimers, each of which comprised one subunit in a closed and one in an open conformation. Although the homodimer asymmetry was most probably caused by crystal packing, it indicates that the enzyme can adopt such a state in solution, which may be relevant for the catalytic reaction.
About this Structure
2V03 is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as Cysteine synthase, with EC number 2.5.1.47 Known structural/functional Sites: , and . Full crystallographic information is available from OCA.
Reference
High resolution structure and catalysis of O-acetylserine sulfhydrylase isozyme B from Escherichia coli., Zocher G, Wiesand U, Schulz GE, FEBS J. 2007 Oct;274(20):5382-9. Epub 2007 Sep 26. PMID:17894825
Page seeded by OCA on Fri Mar 14 09:43:25 2008
