3wnp

D308A, F268V, D469Y, A513V, and Y515S quintuple mutant of Bacillus circulans T-3040 cycloisomaltooligosaccharide glucanotransferase complexed with isomaltoundecaose

spinqualitylabelsall models 3wnp, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3wnp is a 2 chain structure with sequence from Niallia circulans. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.8Å Ligands: BGC, CA, GLC, MES, NA, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CTA1_NIACI Produces cycloisomaltooligosaccharide from dextran containing 7, 8 or 9 glucose units. The enzyme is specific for (1->6)-alpha-D-glucans (dextrans) and, without activity toward (1->4)-alpha-D-glucans, such as amylose. It also has no activity on oligosaccharides, such as amylopectin and pullulan, containing (1->6)-alpha-D-glucosidic linkages at branch points. Publication Abstract from PubMed Cycloisomaltooligosaccharide glucanotransferase (CITase) is a member of the glycoside hydrolase family 66, and it produces cycloisomaltooligosaccharides (CIs). Small CIs (CI-7-9) and large CIs (CI->/=10) are designated as oligosaccharide-type CIs (oligo-CIs) and megalosaccharide-type CIs (megalo-CIs), respectively. CITase from Bacillus circulans T-3040 (BcCITase) produces mainly CI-8 with little megalo-CIs. It has two family 35 carbohydrate-binding modules (BcCBM35-1 and BcCBM35-2). BcCBM35-1 is inserted in a catalytic domain of BcCITase, and BcCBM35-2 is located at the C-terminal region. Our previous studies suggested that BcCBM35-1 has two substrate-binding sites (B-1 and B-2). We implemented site-directed mutagenesis of BcCITase to explore the preference for product size on the basis of the 3D structure of BcCITase. Mutational studies provided evidence that B-1 and B-2 contribute to recruiting substrate and maintaining product size, respectively. A mutant (mutant-R) with four mutations (F268V, D469Y, A513V and Y515S) produced three times as much megalo-CIs (CI-10-12) and 1.5 times as much total CIs (CI-7-12) as compared with the wild-type BcCITase. The 3D structure of the substrate-enzyme complex of mutant-R suggested that the modified product size specificity was attributable to the construction of novel substrate-binding sites in the B-2 site of BcCBM35-1, and reactivity was improved by mutation on subsite -3 on the catalytic domain. Molecular engineering of cycloisomaltooligosaccharide glucanotransferase from Bacillus circulans T-3040: structural determinants for the reaction product size and reactivity.,Suzuki R, Suzuki N, Fujimoto Z, Momma M, Kimura K, Kitamura S, Kimura A, Funane K Biochem J. 2015 Feb 4. PMID:25649478 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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