1i75
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CRYSTAL STRUCTURE OF CYCLODEXTRIN GLUCANOTRANSFERASE FROM ALKALOPHILIC BACILLUS SP.#1011 COMPLEXED WITH 1-DEOXYNOJIRIMYCIN
OverviewOverview
1-Deoxynojirimycin, a pseudo-monosaccharide, is a strong inhibitor of, glucoamylase but a relatively weak inhibitor of cyclodextrin, glucanotransferase (CGTase). To elucidate this difference, the crystal, structure of the CGTase from alkalophilic Bacillus sp. 1011 complexed with, 1-deoxynojirimycin was determined at 2.0 A resolution with the, crystallographic R value of 0.154 (R(free) = 0.214). The asymmetric unit, of the crystal contains two CGTase molecules and each molecule binds two, 1-deoxynojirimycins. One 1-deoxynojirimycin molecule is bound to the, active center by hydrogen bonds with catalytic residues and water, molecules, but its binding mode differs from that expected in the, substrate binding. Another 1-deoxynojirimycin found at the maltose-binding, site 1 is bound to Asn-667 with a hydrogen bond and by stacking, interaction with the indole moiety of Trp-662 of molecule 1 or Trp-616 of, molecule 2. Comparison of this structure with that of the acarbose-CGTase, complex suggested that the lack of stacking interaction with the aromatic, side chain of Tyr-100 is responsible for the weak inhibition by, 1-deoxynojirimycin of the enzymatic action of CGTase.
About this StructureAbout this Structure
1I75 is a Single protein structure of sequence from Bacillus sp. with CA and NOJ as ligands. Active as Cyclomaltodextrin glucanotransferase, with EC number 2.4.1.19 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of cyclodextrin glucanotransferase from alkalophilic Bacillus sp. 1011 complexed with 1-deoxynojirimycin at 2.0 A resolution., Kanai R, Haga K, Yamane K, Harata K, J Biochem (Tokyo). 2001 Apr;129(4):593-8. PMID:11275559
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