2gdu: Difference between revisions

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==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.

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==

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[[Category: Sucrose phosphorylase]]

[[Category: Gajhede, M.]]

[[Category: Kastrup, J.S.]]

[[Category: Kastrup, J S.]]

[[Category: Mirza, O.]]

[[Category: Skov, L.K.]]

[[Category: Skov, L K.]]

[[Category: SUC]]

[[Category: beta-alpha-barrels]]

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[[Category: glycoside hydrolase]]

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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:30:43 2008''

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@@ Line 4: / Line 4: @@
 ==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.
+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==
@@ Line 15: / Line 15: @@
 [[Category: Sucrose phosphorylase]]
 [[Category: Gajhede, M.]]
-[[Category: Kastrup, J.S.]]
+[[Category: Kastrup, J S.]]
 [[Category: Mirza, O.]]
-[[Category: Skov, L.K.]]
+[[Category: Skov, L K.]]
 [[Category: SUC]]
 [[Category: beta-alpha-barrels]]
@@ Line 23: / Line 23: @@
 [[Category: glycoside hydrolase]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jan 29 19:57:20 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:30:43 2008''