1ev7: Difference between revisions

[[Image:1ev7.gif|left|200px]]<br /><applet load="1ev7" size="350" color="white" frame="true" align="right" spinBox="true"  

NAE:I is transformed from DNA endonuclease to DNA topoisomerase and recombinase by a single amino acid substitution. The crystal structure of NAE:I was solved at 2.3 A resolution and shows that NAE:I is a dimeric molecule with two domains per monomer. Each domain contains one potential DNA recognition motif corresponding to either endonuclease or topoisomerase activity. The N-terminal domain core folds like the other type II restriction endonucleases as well as lambda-exonuclease and the DNA repair enzymes MutH and Vsr, implying a common evolutionary origin and catalytic mechanism. The C-terminal domain contains a catabolite activator protein (CAP) motif present in many DNA-binding proteins, including the type IA and type II topoisomerases. Thus, the NAE:I structure implies that DNA processing enzymes evolved from a few common ancestors. NAE:I may be an evolutionary bridge between endonuclease and DNA processing enzymes.

1EV7 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Lechevalieria_aerocolonigenes Lechevalieria aerocolonigenes]. Active as [http://en.wikipedia.org/wiki/Type_II_site-specific_deoxyribonuclease Type II site-specific deoxyribonuclease], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.21.4 3.1.21.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EV7 OCA].  

[[Category: Colandene, J D.]]

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