2ore
From Proteopedia
(New page: 200px<br /><applet load="2ore" size="450" color="white" frame="true" align="right" spinBox="true" caption="2ore, resolution 2.99Å" /> '''Binary Structure of ...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:2ore.gif|left|200px]]<br /><applet load="2ore" size=" | + | [[Image:2ore.gif|left|200px]]<br /><applet load="2ore" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2ore, resolution 2.99Å" /> | caption="2ore, resolution 2.99Å" /> | ||
'''Binary Structure of Escherichia coli DNA Adenine Methyltransferase and S-adenosylhomocysteine'''<br /> | '''Binary Structure of Escherichia coli DNA Adenine Methyltransferase and S-adenosylhomocysteine'''<br /> | ||
| Line 7: | Line 7: | ||
==About this Structure== | ==About this Structure== | ||
| - | 2ORE 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 SO4 and SAH as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Site-specific_DNA-methyltransferase_(adenine-specific) Site-specific DNA-methyltransferase (adenine-specific)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.72 2.1.1.72] Full crystallographic information is available from [http:// | + | 2ORE 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=SO4:'>SO4</scene> and <scene name='pdbligand=SAH:'>SAH</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Site-specific_DNA-methyltransferase_(adenine-specific) Site-specific DNA-methyltransferase (adenine-specific)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.72 2.1.1.72] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2ORE OCA]. |
==Reference== | ==Reference== | ||
| Line 23: | Line 23: | ||
[[Category: s-adenosylhomocysteine conformation]] | [[Category: s-adenosylhomocysteine conformation]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 14:07:24 2008'' |
Revision as of 12:07, 23 January 2008
|
Binary Structure of Escherichia coli DNA Adenine Methyltransferase and S-adenosylhomocysteine
Overview
The crystal structure of the Escherichia coli DNA adenine, methyltransferase (EcoDam) in a binary complex with the cofactor product, S-adenosyl-L-homocysteine (AdoHcy) unexpectedly showed the bound AdoHcy in, two alternative conformations, extended or folded. The extended, conformation represents the catalytically competent conformation, identical to that of EcoDam-DNA-AdoHcy ternary complex. The folded, conformation prevents catalysis, because the homocysteine moiety occupies, the target Ade binding pocket. The largest difference between the binary, and ternary structures is in the conformation of the N-terminal, hexapeptide (K9-W10-A11-G12-G13-K14). Cofactor binding leads to a strong, change in the fluorescence of W10, whose indole ring approaches the, cofactor by 3.3 A. Stopped-flow kinetics and AdoMet crosslinking studies, indicate that the cofactor prefers binding to the enzyme after, pre-incubation with DNA. In the presence of DNA, AdoMet binding is, approximately two-fold stronger than AdoHcy binding. In the binary complex, the side chain of K14 is disordered, while K14 stabilizes the active site, in the ternary complex. Fluorescence stopped-flow experiments indicate, that K14 is important for EcoDam binding of the extrahelical target base, into the active site pocket. This suggests that the hexapeptide couples, specific DNA binding (K9), AdoMet binding (W10) and insertion of the, flipped target base into the active site pocket (K14).
About this Structure
2ORE is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as Site-specific DNA-methyltransferase (adenine-specific), with EC number 2.1.1.72 Full crystallographic information is available from OCA.
Reference
Two alternative conformations of adohcy bound to Escherichia coli DNA adenine methyltransferase and the implication of conformational changes in regulating the catalytic cycle., Liebert K, Horton JR, Chahar S, Orwick M, Cheng X, Jeltsch A, J Biol Chem. 2007 May 31;. PMID:17545164
Page seeded by OCA on Wed Jan 23 14:07:24 2008
