. "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." . . "J. Biol. Chem." . "Beldman G." . "Gajhede M." . "Kastrup J.S." . "van den Broek L.A." . "Mirza O." . "Skov L.K." . "Sprogoe D." . "2006"^^ . "35576-35584" . "Structural rearrangements of sucrose phosphorylase from Bifidobacterium adolescentis during sucrose conversion." . "281" . "doi:10.1074/jbc.M605611200" .