1uu5: Difference between revisions

As part of an ongoing enzyme discovery program to investigate the, properties and catalytic mechanism of glycoside hydrolase family 12 (GH, 12) endoglucanases, a GH family that contains several cellulases that are, of interest in industrial applications, we have solved four new crystal, structures of wild-type Humicola grisea Cel12A in complexes formed by, soaking with cellobiose, cellotetraose, cellopentaose, and a thio-linked, cellotetraose derivative (G2SG2). These complex structures allow mapping, of the non-covalent interactions between the enzyme and the glucosyl chain, bound in subsites -4 to +2 of the enzyme, and shed light on the mechanism, and function of GH 12 cellulases. The unhydrolysed cellopentaose and the, G2SG2 cello-oligomers span the active site of the catalytically active, H.grisea Cel12A enzyme, with the pyranoside bound in subsite -1 displaying, a S31 skew boat conformation. After soaking in cellotetraose, the, cello-oligomer that is found bound in site -4 to -1 contains a, beta-1,3-linkage between the two cellobiose units in the oligomer, which, is believed to have been formed by a transglycosylation reaction that has, occurred during the ligand soak of the protein crystals. The close fit of, this ligand and the binding sites occupied suggest a novel mixed, beta-glucanase activity for this enzyme.

1UU5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Humicola_grisea Humicola grisea] with ACT as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cellulase Cellulase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.4 3.2.1.4] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1UU5 OCA].  

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