1nh8: Difference between revisions

[[Image:1nh8.gif|left|200px]]<br /><applet load="1nh8" size="350" color="white" frame="true" align="right" spinBox="true"  

The N-1-(5'-phosphoribosyl)-ATP transferase catalyzes the first step of the histidine biosynthetic pathway and is regulated by a feedback mechanism by the product histidine. The crystal structures of the N-1-(5'-phosphoribosyl)-ATP transferase from Mycobacterium tuberculosis in complex with inhibitor histidine and AMP has been determined to 1.8 A resolution and without ligands to 2.7 A resolution. The active enzyme exists primarily as a dimer, and the histidine-inhibited form is a hexamer. The structure represents a new fold for a phosphoribosyltransferase, consisting of three continuous domains. The inhibitor AMP binds in the active site cavity formed between the two catalytic domains. A model for the mechanism of allosteric inhibition has been derived from conformational differences between the AMP:His-bound and apo structures.

1NH8 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=SO4:'>SO4</scene>, <scene name='pdbligand=AMP:'>AMP</scene> and <scene name='pdbligand=HIS:'>HIS</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/ATP_phosphoribosyltransferase ATP phosphoribosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.17 2.4.2.17] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NH8 OCA].  

[[Category: Sacchettini, J C.]]

[[Category: TBSGC, TB Structural Genomics Consortium.]]

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