2gq2: Difference between revisions

[[Image:2gq2.gif|left|200px]]<br /><applet load="2gq2" size="350" color="white" frame="true" align="right" spinBox="true"  

The novel flavin-dependent thymidylate synthase, ThyX, is absent in humans but several pathogenic bacteria depend exclusively on ThyX activity to synthesize thymidylate. Reduction of the enzyme-bound FAD by NADPH is suggested to be the critical first step in ThyX catalysis. We soaked Mycobacterium tuberculosis ThyX-FAD-BrdUMP ternary complex crystals in a solution containing NADP+ to gain structural insights into the reductive step of the catalytic cycle. Surprisingly, the NADP+ displaced both FAD and BrdUMP from the active site. In the resultant ThyX-NADP+ binary complex, the AMP moiety is bound in a deep pocket similar to that of the same moiety of FAD in the ternary complex, while the nicotinamide part of NADP+ is engaged in a limited number of contacts with ThyX. The additional 2'-phosphate group attached to the AMP ribose of NADP+ could be accommodated with minor rearrangement of water molecules. The newly introduced 2'-phosphate groups are engaged in water-mediated interactions across the non-crystallographic 2-fold axis of the ThyX tetramer, suggesting possibilities for design of high-affinity bivalent inhibitors of this intriguing enzyme.

2GQ2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mycobacterium_tuberculosis Mycobacterium tuberculosis] with <scene name='pdbligand=IOD:'>IOD</scene>, <scene name='pdbligand=K:'>K</scene>, <scene name='pdbligand=NAP:'>NAP</scene>, <scene name='pdbligand=PGE:'>PGE</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Thymidylate_synthase_(FAD) Thymidylate synthase (FAD)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.148 2.1.1.148] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GQ2 OCA].  

[[Category: Hol, W G.]]

[[Category: Sibley, C H.]]

[[Category: m tuberculosis]]

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