3CGT

STRUCTURE OF CYCLODEXTRIN GLYCOSYLTRANSFERASE COMPLEXED WITH ITS MAIN PRODUCT BETA-CYCLODEXTRIN

Summary for 3CGT

• Entry DOI: 10.2210/pdb3cgt/pdb
• Related PRD ID: PRD_900012
• Descriptor: CYCLODEXTRIN GLYCOSYLTRANSFERASE, Cycloheptakis-(1-4)-(alpha-D-glucopyranose), CALCIUM ION, ... (4 entities in total)
• Functional Keywords: glycosyltransferase, starch degradation, cyclodextrin
• Biological source: Bacillus circulans
• Total number of polymer chains: 1
• Total formula weight: 75740.17

Authors

Schmidt, A.K.,Schulz, G.E. (deposition date: 1998-01-22, release date: 1998-05-27, Last modification date: 2021-11-03)

Primary citation

Schmidt, A.K.,Cottaz, S.,Driguez, H.,Schulz, G.E.
Structure of cyclodextrin glycosyltransferase complexed with a derivative of its main product beta-cyclodextrin.
Biochemistry, 37:5909-5915, 1998

PubMed Abstract: Crystals of the inactive mutant Glu257-->Ala of cyclodextrin glycosyltransferase were soaked with the cyclodextrin (CD) derivative S-(alpha-D-glucopyranosyl)-6-thio-beta-CD. The structural analysis showed its beta-CD moiety with no density indication for the exocyclic glucosyl unit. For steric reasons, however, the position of this unit is restricted to be at only two of the seven glucosyl groups of beta-CD. The analysis indicated that the enzyme can cyclize branched alpha-glucans. The ligated beta-CD moiety revealed how the enzyme binds its predominant cyclic product. The conformation of the ligated beta-CD was intermediate between the more symmetrical conformation in beta-CD dodecahydrate crystals and the conformation of a bound linear alpha-glucan chain. Its scissile bond was displaced by 2.8 A from the position in linear alpha-glucans. Accordingly, the complex represents the situation after the cyclization reaction but before diffusion into the solvent, where a more symmetrical conformation is assumed, or the equivalent state in the reverse reaction. Furthermore, a unifying nomenclature for oligosaccharide-binding subsites in proteins is proposed.

PubMed: 9558324
DOI: 10.1021/bi9729918

Experimental method

X-RAY DIFFRACTION (2.4 Å)