1b63: Difference between revisions

[[Image:1b63.gif|left|200px]]<br /><applet load="1b63" size="350" color="white" frame="true" align="right" spinBox="true"  

The MutL DNA mismatch repair protein has recently been shown to be an ATPase and to belong to an emerging ATPase superfamily that includes DNA topoisomerase II and Hsp90. We report here the crystal structures of a 40 kDa ATPase fragment of E. coli MutL (LN40) complexed with a substrate analog, ADPnP, and with product ADP. More than 60 residues that are disordered in the apoprotein structure become ordered and contribute to both ADPnP binding and dimerization of LN40. Hydrolysis of ATP, signified by subsequent release of the gamma-phosphate, releases two key loops and leads to dissociation of the LN40 dimer. Dimerization of the LN40 region is required for and is the rate-limiting step in ATP hydrolysis by MutL. The ATPase activity of MutL is stimulated by DNA and likely acts as a switch to coordinate DNA mismatch repair.

1B63 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=MG:'>MG</scene>, <scene name='pdbligand=EDO:'>EDO</scene> and <scene name='pdbligand=ANP:'>ANP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B63 OCA].  

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