Download MendeleyOligosaccharide substrate binding in Escherichia coli maltodextrin phosphorylase.
O'Reilly, M., Watson, K.A., Schinzel, R., Palm, D., Johnson, L.N.(1997) Nat Struct Biol 4: 405-412
- PubMed: 9145112
- DOI: https://doi.org/10.1038/nsb0597-405
- Primary Citation of Related Structures:
1AHP - PubMed Abstract:
The crystal structure of E. coli maltodextrin phosphorylase co-crystallized with an oligosaccharide has been solved at 3.0 A resolution, providing the first structure of an oligosaccharide bound at the catalytic site of an alpha-glucan phosphorylase. An induced fit mechanism brings together two domains across the catalytic site tunnel. A stacking interaction between the glucosyl residue and the aromatic group of a tyrosine residue at a sub-site remote (8 A) from the catalytic site provides a key element in substrate recognition; mutation of this residue to Ala decreases the Kcat/Km by 10(4). Extrapolation of the results to substrate binding across the site of attack by phosphorolysis indicates a likely alteration in the glycosidic torsion angles from their preferred values, an alteration that appears to be important for the catalytic mechanism.
Organizational Affiliation:
Laboratory of Molecular Biophysics, University of Oxford.
