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.
(2015) Biochem.J. --: --
- PubMed: 25649478
- DOI: 10.1042/BJ20140860
- PubMed Abstract:
- Deletion analysis of regions at the C-terminal part of cycloisomaltooligosaccharide glucanotransferase from Bacillus circulans T-3040.
Funane, K.,Kawabata, Y.,Suzuki, R.,Kim, Y.M.,Kang, H.K.,Suzuki, N.,Fujimoto, Z.,Kimura, A.,Kobayashi, M.
(2011) Biochim.Biophys.Acta 1814: 428
- Crystallization and preliminary X-ray crystallographic analysis of cycloisomaltooligosaccharide glucanotransferase from Bacillus circulans T-3040.
Suzuki, N.,Kim, Y.M.,Momma, M.,Fujimoto, Z.,Kobayashi, M.,Kimura, A.,Funane, K.
(2013) Acta Crystallogr.,Sect.F 69: 946
Cycloisomaltooligosaccharide glucanotransferase (CITase) is a member of 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 ...
Cycloisomaltooligosaccharide glucanotransferase (CITase) is a member of 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) [Suzuki et al. (2014) J. Biol. Chem. 289, 12040-12051]. 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 (WT) 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.
¶Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Kita-9 Nisi-9, Kita-ku, Sapporo 060-8589, Japan.,*Applied Microbiology Division, National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba 305-8642, Japan.,∥College of Life, Environment, and Advanced Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai 599-8531, Japan.,‡Biomolecular Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba 305-8602, Japan.