| Literature DB >> 15242597 |
Katsuro Yaoi1, Hidemasa Kondo, Natsuko Noro, Mamoru Suzuki, Sakae Tsuda, Yasushi Mitsuishi.
Abstract
Oligoxyloglucan reducing-end-specific cellobiohydrolase (OXG-RCBH; EC 3.2.1.150) is an exoglucanase that recognizes the reducing end of oligoxyloglucan and releases two glucosyl residue segments from the main chain. The X-ray crystal structure of OXG-RCBH determined at 2.2 A resolution reveals a unique feature of this enzyme; OXG-RCBH consists of a tandem repeat of two similar domains, which are both folded into seven-bladed beta-propeller structures. The sequence alignment of the propeller blades, based on the structure, indicates that a weak repeat of the amino acid sequence occurred seven times to construct each domain. There is a cleft that can accommodate the substrate oligosaccharide between the two domains, which is a putative substrate binding subsite. Mutation of either Asp35 or Asp465, located in the putative catalytic center, to Asn resulted in a protein with no detectable catalytic activity, indicating the critical role of these amino acids in catalysis.Entities:
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Year: 2004 PMID： 15242597 DOI： 10.1016/j.str.2004.04.020
Source DB: PubMed Journal: Structure ISSN： 0969-2126 Impact factor: 5.006