5a3h
From Proteopedia
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==Overview== | ==Overview== | ||
| - | The enzymatic hydrolysis of O-glycosidic linkages is one of the most | + | The enzymatic hydrolysis of O-glycosidic linkages is one of the most diverse and widespread reactions in nature and involves a classic "textbook" enzyme mechanism. A multidisciplinary analysis of a beta-glycoside hydrolase, the Cel5A from Bacillus agaradhaerens, is presented in which the structures of each of the native, substrate, covalent-intermediate, and product complexes have been determined and their interconversions analyzed kinetically, providing unprecedented insights into the mechanism of this enzyme class. Substrate is bound in a distorted 1S3 skew-boat conformation, thereby presenting the anomeric carbon appropriately for nucleophilic attack as well as satisfying the stereoelectronic requirements for an incipient oxocarbenium ion. Leaving group departure results in the trapping of a covalent alpha-glycosyl-enzyme intermediate in which the sugar adopts an undistorted 4C1 conformation. Finally, hydrolysis of this intermediate yields a product complex in which the sugar is bound in a partially disordered mode, consistent with unfavorable interactions and low product affinity. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Cellulase]] | [[Category: Cellulase]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Brzozowski, A | + | [[Category: Brzozowski, A M.]] |
[[Category: Dauter, M.]] | [[Category: Dauter, M.]] | ||
| - | [[Category: Davies, G | + | [[Category: Davies, G J.]] |
[[Category: Mackenzie, L.]] | [[Category: Mackenzie, L.]] | ||
[[Category: Schulein, M.]] | [[Category: Schulein, M.]] | ||
[[Category: Varrot, A.]] | [[Category: Varrot, A.]] | ||
| - | [[Category: Withers, S | + | [[Category: Withers, S G.]] |
[[Category: FFC]] | [[Category: FFC]] | ||
[[Category: cellulose degradation]] | [[Category: cellulose degradation]] | ||
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[[Category: skew-boat]] | [[Category: skew-boat]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:14:44 2008'' |
Revision as of 17:14, 21 February 2008
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2-DEOXY-2-FLURO-B-D-CELLOBIOSYL/ENZYME INTERMEDIATE COMPLEX OF THE ENDOGLUCANASE CEL5A FROM BACILLUS AGARADHEARANS AT 1.8 ANGSTROMS RESOLUTION
Overview
The enzymatic hydrolysis of O-glycosidic linkages is one of the most diverse and widespread reactions in nature and involves a classic "textbook" enzyme mechanism. A multidisciplinary analysis of a beta-glycoside hydrolase, the Cel5A from Bacillus agaradhaerens, is presented in which the structures of each of the native, substrate, covalent-intermediate, and product complexes have been determined and their interconversions analyzed kinetically, providing unprecedented insights into the mechanism of this enzyme class. Substrate is bound in a distorted 1S3 skew-boat conformation, thereby presenting the anomeric carbon appropriately for nucleophilic attack as well as satisfying the stereoelectronic requirements for an incipient oxocarbenium ion. Leaving group departure results in the trapping of a covalent alpha-glycosyl-enzyme intermediate in which the sugar adopts an undistorted 4C1 conformation. Finally, hydrolysis of this intermediate yields a product complex in which the sugar is bound in a partially disordered mode, consistent with unfavorable interactions and low product affinity.
About this Structure
5A3H is a Single protein structure of sequence from Bacillus agaradhaerens with as ligand. Active as Cellulase, with EC number 3.2.1.4 Known structural/functional Sites: and . Full crystallographic information is available from OCA.
Reference
Snapshots along an enzymatic reaction coordinate: analysis of a retaining beta-glycoside hydrolase., Davies GJ, Mackenzie L, Varrot A, Dauter M, Brzozowski AM, Schulein M, Withers SG, Biochemistry. 1998 Aug 25;37(34):11707-13. PMID:9718293
Page seeded by OCA on Thu Feb 21 19:14:44 2008
Categories: Bacillus agaradhaerens | Cellulase | Single protein | Brzozowski, A M. | Dauter, M. | Davies, G J. | Mackenzie, L. | Schulein, M. | Varrot, A. | Withers, S G. | FFC | Cellulose degradation | Distortion | Endoglucanase | Glycoside hydrolase family 5 | Hydrolase | Michaelis complex | Skew-boat
