2gdu
From Proteopedia
E232Q mutant of sucrose phosphorylase from BIFIDOBACTERIUM ADOLESCENTIS in complex with sucrose
Overview
The reaction mechanism of sucrose phosphorylase from Bifidobacterium adolescentis (BiSP) was studied by site-directed mutagenesis and x-ray crystallography. An inactive mutant of BiSP (E232Q) was co-crystallized with sucrose. The structure revealed a substrate-binding mode comparable with that seen in other related sucrose-acting enzymes. Wild-type BiSP was also crystallized in the presence of sucrose. In the dimeric structure, a covalent glucosyl intermediate was formed in one molecule of the BiSP dimer, and after hydrolysis of the glucosyl intermediate, a beta-D-glucose product complex was formed in the other molecule. Although the overall structure of the BiSP-glucosyl intermediate complex is similar to that of the BiSP(E232Q)-sucrose complex, the glucose complex discloses major differences in loop conformations. Two loops (residues 336-344 and 132-137) in the proximity of the active site move up to 16 and 4 A, respectively. On the basis of these findings, we have suggested a reaction cycle that takes into account the large movements in the active-site entrance loops.
About this Structure
2GDU is a Single protein structure of sequence from Bifidobacterium adolescentis. Full crystallographic information is available from OCA.
Reference
Structural rearrangements of sucrose phosphorylase from Bifidobacterium adolescentis during sucrose conversion., Mirza O, Skov LK, Sprogoe D, van den Broek LA, Beldman G, Kastrup JS, Gajhede M, J Biol Chem. 2006 Nov 17;281(46):35576-84. Epub 2006 Sep 21. PMID:16990265 Page seeded by OCA on Sun May 4 04:59:33 2008
