1ixy: Difference between revisions

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

T4 phage beta-glucosyltransferase (BGT) modifies T4 DNA. We crystallized BGT with UDP-glucose and a 13mer DNA fragment containing an abasic site. We obtained two crystal structures of a ternary complex BGT-UDP-DNA at 1.8A and 2.5A resolution, one with a Tris molecule and the other with a metal ion at the active site. Both structures reveal a large distortion in the bound DNA. BGT flips the deoxyribose moiety at the abasic site to an extra-helical position and induces a 40 degrees bend in the DNA with a marked widening of the major groove. The Tris molecule mimics the glucose moiety in its transition state. The base-flipping mechanism, which has so far been observed only for glycosylases, methyltransferases and endonucleases, is now reported for a glucosyltransferase. BGT is unique in binding and inserting a loop into the DNA duplex through the major groove only. Furthermore, BGT compresses the backbone DNA one base further than the target base on the 3'-side.

1IXY 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=MG:'>MG</scene>, <scene name='pdbligand=UDP:'>UDP</scene> and <scene name='pdbligand=MPD:'>MPD</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=1IXY OCA].  

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