2owc
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(New page: 200px<br /><applet load="2owc" size="450" color="white" frame="true" align="right" spinBox="true" caption="2owc, resolution 2.05Å" /> '''Structure of a coval...)
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Revision as of 11:12, 21 November 2007
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Structure of a covalent intermediate in Thermus thermophilus amylomaltase
Overview
Amylomaltases are glycosyl hydrolases belonging to glycoside hydrolase, family 77 that are capable of the synthesis of large cyclic glucans and, the disproportionation of oligosaccharides. Using protein crystallography, we have generated a flip-book movie of the amylomaltase catalytic cycle in, atomic detail. The structures include a covalent glycosyl-enzyme, intermediate, and a covalent intermediate in complex with an analogue of a, co-substrate, and show how the structures of both enzyme and substrate, respond to the changes required by the catalytic cycle as it proceeds., Notably, the catalytic nucleophile changes conformation dramatically, during the reaction. Also, Gln256 on the 250s loop is involved in, orienting the substrate in the +1 site. The absence of a suitable base in, the covalent intermediate structure explains the low hydrolysis activity.
About this Structure
2OWC is a Single protein structure of sequence from Thermus thermophilus with ACR, MLI and GOL as ligands. Active as 4-alpha-glucanotransferase, with EC number 2.4.1.25 Full crystallographic information is available from OCA.
Reference
Three-way stabilization of the covalent intermediate in amylomaltase, an alpha-amylase-like transglycosylase., Barends TR, Bultema JB, Kaper T, van der Maarel MJ, Dijkhuizen L, Dijkstra BW, J Biol Chem. 2007 Apr 9;. PMID:17420245
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