1cem
From Proteopedia
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'''ENDOGLUCANASE A (CELA) CATALYTIC CORE, RESIDUES 33-395''' | '''ENDOGLUCANASE A (CELA) CATALYTIC CORE, RESIDUES 33-395''' | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Alzari, P M.]] | [[Category: Alzari, P M.]] | ||
| - | [[Category: | + | [[Category: Cellulase]] |
| - | [[Category: | + | [[Category: Clostridium thermocellum]] |
| - | [[Category: | + | [[Category: Family d/8 of glycosyl hydrolase]] |
| - | [[Category: | + | [[Category: Glycosyl hydrolase]] |
| - | [[Category: | + | [[Category: Glycosyltransferase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 12:38:56 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 09:38, 2 May 2008
ENDOGLUCANASE A (CELA) CATALYTIC CORE, RESIDUES 33-395
Overview
BACKGROUND. Cellulases, which catalyze the hydrolysis of glycosidic bonds in cellulose, can be classified into several different protein families. Endoglucanase CelA is a member of glycosyl hydrolase family 8, a family for which no structural information was previously available. RESULTS. The crystal structure of CelA was determined by multiple isomorphous replacement and refined to 1.65 A resolution. The protein folds into a regular (alpha/alpha)6 barrel formed by six inner and six outer alpha helices. Cello-oligosaccharides bind to an acidic cleft containing at least five D-glucosyl-binding subsites (A-E) such that the scissile glycosidic linkage lies between subsites C and D. The strictly conserved residue Glu95, which occupies the center of the substrate-binding cleft and is hydrogen bonded to the glycosidic oxygen, has been assigned the catalytic role of proton donor. CONCLUSIONS. The present analysis provides a basis for modeling homologous family 8 cellulases. The architecture of the active-site cleft, presenting at least five glucosyl-binding subsites, explains why family 8 cellulases cleave cello-oligosaccharide polymers that are at least five D-glycosyl subunits long. Furthermore, the structure of CelA allows comparison with (alpha/alpha)6 barrel glycosidases that are not related in sequence, suggesting a possible, albeit distant, evolutionary relationship between different families of glycosyl hydrolases.
About this Structure
1CEM is a Single protein structure of sequence from Clostridium thermocellum. Full crystallographic information is available from OCA.
Reference
The crystal structure of endoglucanase CelA, a family 8 glycosyl hydrolase from Clostridium thermocellum., Alzari PM, Souchon H, Dominguez R, Structure. 1996 Mar 15;4(3):265-75. PMID:8805535 Page seeded by OCA on Fri May 2 12:38:56 2008
