1nzf: Difference between revisions

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

T4 phage beta-glucosyltransferase (BGT) is an inverting glycosyltransferase (GT) that transfers glucose from uridine diphospho-glucose (UDP-glucose) to an acceptor modified DNA. BGT belongs to the GT-B structural superfamily, represented, so far, by five different inverting or retaining GT families. Here, we report three high-resolution X-ray structures of BGT and a point mutant solved in the presence of UDP-glucose. The two co-crystal structures of the D100A mutant show that, unlike the wild-type enzyme, this mutation prevents glucose hydrolysis. This strongly indicates that Asp100 is the catalytic base. We obtained the wild-type BGT-UDP-glucose complex by soaking substrate-free BGT crystals. Comparison with a previous structure of BGT solved in the presence of the donor product UDP and an acceptor analogue provides the first model of an inverting GT-B enzyme in which both the donor and acceptor substrates are bound to the active site. The structural analyses support the in-line displacement reaction mechanism previously proposed, locate residues involved in donor substrate specificity and identify the catalytic base.

1NZF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4] with <scene name='pdbligand=CL:'>CL</scene>, <scene name='pdbligand=UPG:'>UPG</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/DNA_beta-glucosyltransferase DNA beta-glucosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.27 2.4.1.27] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NZF OCA].  

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