1sqj: Difference between revisions

[[Image:1sqj.gif|left|200px]]<br /><applet load="1sqj" size="350" color="white" frame="true" align="right" spinBox="true"  

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.

1SQJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Geotrichum_sp._m128 Geotrichum sp. m128]. Active as [http://en.wikipedia.org/wiki/Oligoxyloglucan_reducing-end-specific_cellobiohydrolase Oligoxyloglucan reducing-end-specific cellobiohydrolase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.150 3.2.1.150] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SQJ OCA].  

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