1J8V

Crystal structure of barley beta-D-glucan glucohydrolase isoenzyme Exo1 in complex with 4'-nitrophenyl 3I-thiolaminaritrioside

Summary for 1J8V

• Entry DOI: 10.2210/pdb1j8v/pdb
• Related: 1EX1 1IEQ
• Descriptor: Beta-D-glucan glucohydrolase isoenzyme EXO1, beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-2)-alpha-D-mannopyranose-(1-6)-beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[alpha-L-fucopyranose-(1-3)]2-acetamido-2-deoxy-beta-D-glucopyranose, ... (6 entities in total)
• Functional Keywords: 2-domain fold, ligand-protein complex, hydrolase
• Biological source: Hordeum vulgare
• Total number of polymer chains: 1
• Total formula weight: 68226.17

Authors

Hrmova, M.,De Gori, R.,Smith, B.J.,Fairweather, J.K.,Driguez, H.,Varghese, J.N.,Fincher, G.B. (deposition date: 2001-05-22, release date: 2002-06-12, Last modification date: 2024-10-16)

Primary citation

Hrmova, M.,De Gori, R.,Smith, B.J.,Fairweather, J.K.,Driguez, H.,Varghese, J.N.,Fincher, G.B.
Structural basis for broad substrate specificity in higher plant beta-D-glucan glucohydrolases.
Plant Cell, 14:1033-1052, 2002

PubMed Abstract: Family 3 beta-D-glucan glucohydrolases are distributed widely in higher plants. The enzymes catalyze the hydrolytic removal of beta-D-glucosyl residues from nonreducing termini of a range of beta-D-glucans and beta-D-oligoglucosides. Their broad specificity can be explained by x-ray crystallographic data obtained from a barley beta-D-glucan glucohydrolase in complex with nonhydrolyzable S-glycoside substrate analogs and by molecular modeling of enzyme/substrate complexes. The glucosyl residue that occupies binding subsite -1 is locked tightly into a fixed position through extensive hydrogen bonding with six amino acid residues near the bottom of an active site pocket. In contrast, the glucosyl residue at subsite +1 is located between two Trp residues at the entrance of the pocket, where it is constrained less tightly. The relative flexibility of binding at subsite +1, coupled with the projection of the remainder of bound substrate away from the enzyme's surface, means that the overall active site can accommodate a range of substrates with variable spatial dispositions of adjacent beta-D-glucosyl residues. The broad specificity for glycosidic linkage type enables the enzyme to perform diverse functions during plant development.

PubMed: 12034895
DOI: 10.1105/tpc.010442

Experimental method

X-RAY DIFFRACTION (2.4 Å)