1szn
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THE STRUCTURE OF ALPHA-GALACTOSIDASE
OverviewOverview
The crystal structures of alpha-galactosidase from the mesophilic fungus, Trichoderma reesei and its complex with the competitive inhibitor, beta-d-galactose, have been determined at 1.54 A and 2.0 A resolution, respectively. The alpha-galactosidase structure was solved by the quick, cryo-soaking method using a single Cs derivative. The refined, crystallographic model of the alpha-galactosidase consists of two domains, an N-terminal catalytic domain of the (beta/alpha)8 barrel topology and a, C-terminal domain which is formed by an antiparallel beta-structure. The, protein contains four N-glycosylation sites located in the catalytic, domain. Some of the oligosaccharides were found to participate in, inter-domain contacts. The galactose molecule binds to the active site, pocket located in the center of the barrel of the catalytic domain., Analysis of the alpha-galactosidase- galactose complex reveals the, residues of the active site and offers a structural basis for, identification of the putative mechanism of the enzymatic reaction. The, structure of the alpha-galactosidase closely resembles those of the, glycoside hydrolase family 27. The conservation of two catalytic Asp, residues, identified for this family, is consistent with a, double-displacement reaction mechanism for the alpha-galactosidase., Modeling of possible substrates into the active site reveals specific, hydrogen bonds and hydrophobic interactions that could explain, peculiarities of the enzyme kinetics.
About this StructureAbout this Structure
1SZN is a Single protein structure of sequence from Hypocrea jecorina with GOL as ligand. Active as Alpha-galactosidase, with EC number 3.2.1.22 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of alpha-galactosidase from Trichoderma reesei and its complex with galactose: implications for catalytic mechanism., Golubev AM, Nagem RA, Brandao Neto JR, Neustroev KN, Eneyskaya EV, Kulminskaya AA, Shabalin KA, Savel'ev AN, Polikarpov I, J Mol Biol. 2004 May 28;339(2):413-22. PMID:15136043
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