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| [[Image:2pfq.gif|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_2pfq| PDB=2pfq | SCENE= }} | | {{STRUCTURE_2pfq| PDB=2pfq | SCENE= }} |
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| '''Manganese promotes catalysis in a DNA polymerase lambda-DNA crystal'''
| | ===Manganese promotes catalysis in a DNA polymerase lambda-DNA crystal=== |
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| ==Overview==
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| The incorporation of dNMPs into DNA by polymerases involves a phosphoryl transfer reaction hypothesized to require two divalent metal ions. Here we investigate this hypothesis using as a model human DNA polymerase lambda (Pol lambda), an enzyme suggested to be activated in vivo by manganese. We report the crystal structures of four complexes of human Pol lambda. In a 1.9 A structure of Pol lambda containing a 3'-OH and the non-hydrolyzable analog dUpnpp, a non-catalytic Na+ ion occupies the site for metal A and the ribose of the primer-terminal nucleotide is found in a conformation that positions the acceptor 3'-OH out of line with the alpha-phosphate and the bridging oxygen of the pyrophosphate leaving group. Soaking this crystal in MnCl2 yielded a 2.0 A structure with Mn2+ occupying the site for metal A. In the presence of Mn2+, the conformation of the ribose is C3'-endo and the 3'-oxygen is in line with the leaving oxygen, at a distance from the phosphorus atom of the alpha-phosphate (3.69 A) consistent with and supporting a catalytic mechanism involving two divalent metal ions. Finally, soaking with MnCl2 converted a pre-catalytic Pol lambda/Na+ complex with unreacted dCTP in the active site into a product complex via catalysis in the crystal. These data provide pre- and post-transition state information and outline in a single crystal the pathway for the phosphoryl transfer reaction carried out by DNA polymerases. | | The line below this paragraph, {{ABSTRACT_PUBMED_17475573}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 17475573 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_17475573}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Manganese]] | | [[Category: Manganese]] |
| [[Category: Phosphoryl transfer reaction]] | | [[Category: Phosphoryl transfer reaction]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 13:01:23 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 05:44:04 2008'' |
