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Updated: Jul 13, 2026

Concanavalin A-Based Sedimentation Assay to Measure Substrate Binding of Glucan Phosphatases
Published on: December 23, 2022
Identification of structural determinants for substrate binding and turnover by glucosyltransferase R supports the
Anna Maria Swistowska1, Sabine Gronert, Sabine Wittrock
1Division of Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany.
Abstract:
Segments that may crucially influence the catalytic behaviour of glucosyltransferases of the glucansucrase type were selected for modification. This was done by sequence alignments, followed by structural modelling of the putative catalytic domain, based on a permuted form of the glucosyltransferase R (GtfR) of Streptococcus oralis. Five selected regions, located in the C-terminal half of the potential catalytic domain, were replaced by segments found at equivalent positions in other glucosyltransferases. The exchanges of four of these regions significantly affected catalysis by GtfR. This identified C-terminal determinants for substrate binding and turnover and supports the so-called permutation hypothesis with respect to enzymes of the glucansucrase type. Based on the model, roles are proposed for specific residues. Major effects appear to involve a re-positioning of the C-terminal Tyr965 that very likely serves as a hydrophobic platform for the substrate.
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