1r7a
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Sucrose Phosphorylase from Bifidobacterium adolescentis
OverviewOverview
Around 80 enzymes are implicated in the generic starch and sucrose, pathways. One of these enzymes is sucrose phosphorylase, which reversibly, catalyzes the conversion of sucrose and orthophosphate to d-Fructose and, alpha-d-glucose 1-phosphate. Here, we present the crystal structure of, sucrose phosphorylase from Bifidobacterium adolescentis (BiSP) refined at, 1.77 A resolution. It represents the first 3D structure of a sucrose, phosphorylase and is the first structure of a phosphate-dependent enzyme, from the glycoside hydrolase family 13. The structure of BiSP is composed, of the four domains A, B, B', and C. Domain A comprises the, (beta/alpha)(8)-barrel common to family 13. The catalytic active-site, residues (Asp192 and Glu232) are located at the tips of beta-sheets 4 and, 5 in the (beta/alpha)(8)-barrel, as required for family 13 members. The, topology of the B' domain disfavors oligosaccharide binding and reduces, the size of the substrate access channel compared to other family 13, members, underlining the role of this domain in modulating the function of, these enzymes. It is remarkable that the fold of the C domain is not, observed in any other known hydrolases of family 13. BiSP was found as a, homodimer in the crystal, and a dimer contact surface area of 960 A(2) per, monomer was calculated. The majority of the interactions are confined to, the two B domains, but interactions between the loop 8 regions of the two, barrels are also observed. This results in a large cavity in the dimer, including the entrance to the two active sites.
About this StructureAbout this Structure
1R7A is a Single protein structure of sequence from Bifidobacterium adolescentis with TRS as ligand. Active as Sucrose phosphorylase, with EC number 2.4.1.7 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of sucrose phosphorylase from Bifidobacterium adolescentis., Sprogoe D, van den Broek LA, Mirza O, Kastrup JS, Voragen AG, Gajhede M, Skov LK, Biochemistry. 2004 Feb 10;43(5):1156-62. PMID:14756551
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