Crystal structure of a 117 kDa glucansucrase fragment provides insight into evolution and product specificity of GH70 enzymes
- 30 November 2010
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 107 (50), 21406-21411
- https://doi.org/10.1073/pnas.1007531107
Abstract
Glucansucrases are large enzymes belonging to glycoside hydrolase family 70, which catalyze the cleavage of sucrose into fructose and glucose, with the concomitant transfer of the glucose residue to a growing α-glucan polymer. Among others, plaque-forming oral bacteria secrete these enzymes to produce α-glucans, which facilitate the adhesion of the bacteria to the tooth enamel. We determined the crystal structure of a fully active, 1,031-residue fragment encompassing the catalytic and C-terminal domains of GTF180 from Lactobacillus reuteri 180, both in the native state, and in complexes with sucrose and maltose. These structures show that the enzyme has an α-amylase-like (β/α)(8)-barrel catalytic domain that is circularly permuted compared to the catalytic domains of members of glycoside hydrolase families 13 and 77, which belong to the same GH-H superfamily. In contrast to previous suggestions, the enzyme has only one active site and one nucleophilic residue. Surprisingly, in GTF180 the peptide chain follows a "U"-path, such that four of the five domains are made up from discontiguous N- and C-terminal stretches of the peptide chain. Finally, the structures give insight into the factors that determine the different linkage types in the polymeric product.Keywords
This publication has 46 references indexed in Scilit:
- MolProbity: all-atom contacts and structure validation for proteins and nucleic acidsNucleic Acids Research, 2007
- Coot: model-building tools for molecular graphicsActa crystallographica. Section D, Structural biology, 2004
- Crystal Structure of the Covalent Intermediate of Amylosucrase from Neisseria polysacchareaBiochemistry, 2004
- Inhibition of Catalytic and Glucan-Binding Activities of a Streptococcal GTF Forming Insoluble GlucansCaries Research, 2002
- Glucansucrases: mechanism of action and structure–function relationshipsFEMS Microbiology Reviews, 1999
- Trapping and Characterization of the Reaction Intermediate in Cyclodextrin Glycosyltransferase by Use of Activated Substrates and a Mutant EnzymeBiochemistry, 1997
- Refinement of Macromolecular Structures by the Maximum-Likelihood MethodActa crystallographica. Section D, Structural biology, 1997
- A circularly permuted α‐amylase‐type α/β‐barrel structure in glucan‐synthesizing glucosyltransferasesFEBS Letters, 1996
- The CCP4 suite: programs for protein crystallographyActa crystallographica. Section D, Structural biology, 1994
- Why is sucrose so cariogenic? The role of glucosyltransferase and polysaccharidesEuropean Journal of Oral Sciences, 1989