2ore: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:2ore.gif|left|200px]] | [[Image:2ore.gif|left|200px]] | ||
'''Binary Structure of Escherichia coli DNA Adenine Methyltransferase and S-adenosylhomocysteine''' | {{Structure | ||
|PDB= 2ore |SIZE=350|CAPTION= <scene name='initialview01'>2ore</scene>, resolution 2.99Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene> and <scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</scene> | |||
|ACTIVITY= [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] | |||
|GENE= dam ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli]) | |||
}} | |||
'''Binary Structure of Escherichia coli DNA Adenine Methyltransferase and S-adenosylhomocysteine''' | |||
==Overview== | ==Overview== | ||
| Line 7: | Line 16: | ||
==About this Structure== | ==About this Structure== | ||
2ORE is a [ | 2ORE is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2ORE OCA]. | ||
==Reference== | ==Reference== | ||
Two alternative conformations of S-adenosyl-L-homocysteine 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 Aug 3;282(31):22848-55. Epub 2007 May 31. PMID:[http:// | Two alternative conformations of S-adenosyl-L-homocysteine 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 Aug 3;282(31):22848-55. Epub 2007 May 31. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/17545164 17545164] | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| Line 23: | Line 32: | ||
[[Category: s-adenosylhomocysteine conformation]] | [[Category: s-adenosylhomocysteine conformation]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 18:03:29 2008'' | ||
Revision as of 19:03, 20 March 2008
| |||||||
| , resolution 2.99Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | and | ||||||
| Gene: | dam (Escherichia coli) | ||||||
| Activity: | Site-specific DNA-methyltransferase (adenine-specific), with EC number 2.1.1.72 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Binary Structure of Escherichia coli DNA Adenine Methyltransferase and S-adenosylhomocysteine
OverviewOverview
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 ((9)KWAGGK(14)). Cofactor binding leads to a strong change in the fluorescence of Trp(10), whose indole ring approaches the cofactor by 3.3A(.) Stopped-flow kinetics and AdoMet cross-linking studies indicate that the cofactor prefers binding to the enzyme after preincubation with DNA. In the presence of DNA, AdoMet binding is approximately 2-fold stronger than AdoHcy binding. In the binary complex the side chain of Lys(14) is disordered, whereas Lys(14) stabilizes the active site in the ternary complex. Fluorescence stopped-flow experiments indicate that Lys(14) is important for EcoDam binding of the extrahelical target base into the active site pocket. This suggests that the hexapeptide couples specific DNA binding (Lys(9)), AdoMet binding (Trp(10)), and insertion of the flipped target base into the active site pocket (Lys(14)).
About this StructureAbout this Structure
2ORE is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Two alternative conformations of S-adenosyl-L-homocysteine 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 Aug 3;282(31):22848-55. Epub 2007 May 31. PMID:17545164
Page seeded by OCA on Thu Mar 20 18:03:29 2008