1gpi: Difference between revisions

Cellobiohydrolase 58 (Cel7D) is the major cellulase produced by the, white-rot fungus Phanerochaete chrysosporium, constituting approximately, 10 % of the total secreted protein in liquid culture on cellulose. The, enzyme is classified into family 7 of the glycosyl hydrolases, together, with cellobiohydrolase I (Cel7A) and endoglucanase I (Cel7B) from, Trichoderma reesei. Like those enzymes, it catalyses cellulose hydrolysis, with net retention of the anomeric carbon configuration.The structure of, the catalytic module (431 residues) of Cel7D was determined at 3.0 A, resolution using the structure of Cel7A from T. reesei as a search model, in molecular replacement, and ultimately refined at 1.32 A resolution. The, core structure is a beta-sandwich composed of two large and mainly, antiparallel beta-sheets packed onto each other. A long cellulose-binding, groove is formed by loops on one face of the sandwich. The catalytic, residues are conserved and the mechanism is expected to be the same as for, other family members. The Phanerochaete Cel7D binding site is more open, than that of the T. reesei cellobiohydrolase, as a result of deletions and, other changes in the loop regions, which may explain observed differences, in catalytic properties. The binding site is not, however, as open as the, groove of the corresponding endoglucanase. A tyrosine residue at the, entrance of the tunnel may be part of an additional subsite not present in, the T. reesei cellobiohydrolase.The Cel7D structure was used to model the, products of the five other family 7 genes found in P. chrysosporium. The, results suggest that at least two of these will have differences in, specificity and possibly catalytic mechanism, thus offering some, explanation for the presence of Cel7 isozymes in this species, which are, differentially expressed in response to various growth conditions.

1GPI is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Phanerochaete_chrysosporium Phanerochaete chrysosporium] with NAG as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cellulose_1,4-beta-cellobiosidase Cellulose 1,4-beta-cellobiosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.91 3.2.1.91] Structure known Active Site: CAT. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1GPI OCA].  

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