Mixed-Linkage Cellooligosaccharides: A New Class of Glycoside Hydrolase InhibitorsFort, S., Varrot, A., Schulein, M., Cottaz, S., Driguez, H., Davies, G.J.
(2001) Chembiochem 2: 319
- PubMed: 11828460
- DOI: 10.1002/1439-7633(20010504)2:5<319::AID-CBIC319>3.0.CO;2-Q
- Structures With Same Primary Citation
- PubMed Abstract:
A new class of inhibitors for beta-D-glycoside hydrolases, in which a single alpha-(1-->4)-glycosidic bond is incorporated into an otherwise all-beta-(1-->4)-linked oligosaccharide, is described. Such mixed beta/alpha-linkage cellooligosaccharides ar ...
A new class of inhibitors for beta-D-glycoside hydrolases, in which a single alpha-(1-->4)-glycosidic bond is incorporated into an otherwise all-beta-(1-->4)-linked oligosaccharide, is described. Such mixed beta/alpha-linkage cellooligosaccharides are not transition-state mimics, but instead are capable of utilising binding energy from numerous subsites, spanning either side of the catalytic centre, without the need for substrate distortion. This binding is significant; a mixed alpha/beta-D-tetrasaccharide acts competitively on a number of cellulases, displaying inhibition constants in the range of 40-300 microM. Using the Bacillus agaradhaerens enzyme Cel5A as a model system, one such mixed beta/alpha-cellooligosaccharide, methyl 4(II),4(III)-dithio-alpha-cellobiosyl-(1-->4)-beta-cellobioside, displays a K(i) value of 100 microM, an inhibition at least 150 times better than is observed with an equivalent all-beta-linked compound. The three-dimensional structure of B. agaradhaerens Cel5A in complex with methyl 4(II),4(III)-dithio-alpha-cellobiosyl-(1-->4)-beta-cellobioside has been determined at 1.8 A resolution. This confirms the expected mode of binding in which the ligand, with all four pyranosides in the (4)C(1) chair conformation, occupies the -3, -2 and +1 subsites whilst evading the catalytic (-1) subsite. Such "by-pass" compounds offer great scope for the development of a new class of beta-D-glycoside hydrolase inhibitors.
Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS), Affiliated with Université Joseph Fourier, Grenoble B.P. 53, 38041 Grenoble cedex 9, France.