1ryh: Difference between revisions

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

Rac1b was recently identified in malignant colorectal tumors as an alternative splice variant of Rac1 containing a 19-amino acid insertion next to the switch II region. The structures of Rac1b in the GDP- and the GppNHp-bound forms, determined at a resolution of 1.75 A, reveal that the insertion induces an open switch I conformation and a highly mobile switch II. As a consequence, Rac1b has an accelerated GEF-independent GDP/GTP exchange and an impaired GTP hydrolysis, which is restored partially by GTPase-activating proteins. Interestingly, Rac1b is able to bind the GTPase-binding domain of PAK but not full-length PAK in a GTP-dependent manner, suggesting that the insertion does not completely abolish effector interaction. The presented study provides insights into the structural and biochemical mechanism of a self-activating GTPase.

1RYH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=GNP:'>GNP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Small_monomeric_GTPase Small monomeric GTPase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.6.5.2 3.6.5.2] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RYH OCA].  

[[Category: Ahmadian, M R.]]

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