1x1a
From Proteopedia
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|PDB= 1x1a |SIZE=350|CAPTION= <scene name='initialview01'>1x1a</scene>, resolution 2.60Å | |PDB= 1x1a |SIZE=350|CAPTION= <scene name='initialview01'>1x1a</scene>, resolution 2.60Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand= | + | |LIGAND= <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=SAM:S-ADENOSYLMETHIONINE'>SAM</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene> |
|ACTIVITY= | |ACTIVITY= | ||
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY=[[1x19|1X19]], [[1x1b|1X1B]], [[1x1c|1X1C]], [[1x1d|1X1D]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1x1a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1x1a OCA], [http://www.ebi.ac.uk/pdbsum/1x1a PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1x1a RCSB]</span> | ||
}} | }} | ||
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[[Category: Wada, K.]] | [[Category: Wada, K.]] | ||
[[Category: Yamaguchi, H.]] | [[Category: Yamaguchi, H.]] | ||
| - | [[Category: GOL]] | ||
| - | [[Category: SAM]] | ||
| - | [[Category: SO4]] | ||
[[Category: ado-hcy]] | [[Category: ado-hcy]] | ||
[[Category: ado-met]] | [[Category: ado-met]] | ||
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[[Category: sam]] | [[Category: sam]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 00:43:33 2008'' |
Revision as of 21:43, 30 March 2008
| |||||||
| , resolution 2.60Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , | ||||||
| Related: | 1X19, 1X1B, 1X1C, 1X1D
| ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal structure of BchU complexed with S-adenosyl-L-methionine
Overview
BchU plays a role in bacteriochlorophyll c biosynthesis by catalyzing methylation at the C-20 position of cyclic tetrapyrrole chlorin using S-adenosylmethionine (SAM) as a methyl source. This methylation causes red-shifts of the electronic absorption spectrum of the light-harvesting pigment, allowing green photosynthetic bacteria to adapt to low-light environments. We have determined the crystal structures of BchU and its complex with S-adenosylhomocysteine (SAH). BchU forms a dimer and each subunit consists of two domains, an N-terminal domain and a C-terminal domain. Dimerization occurs through interactions between the N-terminal domains and the residues responsible for the catalytic reaction are in the C-terminal domain. The binding site of SAH is located in a large cavity between the two domains, where SAH is specifically recognized by many hydrogen bonds and a salt-bridge. The electron density map of BchU in complex with an analog of bacteriochlorophyll c located its central metal near the SAH-binding site, but the tetrapyrrole ring was invisible, suggesting that binding of the ring to BchU is loose and/or occupancy of the ring is low. It is likely that His290 acts as a ligand for the central metal of the substrate. The orientation of the substrate was predicted by simulation, and allows us to propose a mechanism for the BchU directed methylation: the strictly conserved Tyr246 residue acts catalytically in the direct transfer of the methyl group from SAM to the substrate through an S(N)2-like mechanism.
About this Structure
1X1A is a Single protein structure of sequence from Chlorobaculum tepidum. Full crystallographic information is available from OCA.
Reference
Crystal structures of BchU, a methyltransferase involved in bacteriochlorophyll c biosynthesis, and its complex with S-adenosylhomocysteine: implications for reaction mechanism., Wada K, Yamaguchi H, Harada J, Niimi K, Osumi S, Saga Y, Oh-Oka H, Tamiaki H, Fukuyama K, J Mol Biol. 2006 Jul 21;360(4):839-49. Epub 2006 Jun 8. PMID:16797589
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