This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.


1x1b

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
-
[[Image:1x1b.gif|left|200px]]
+
{{Seed}}
 +
[[Image:1x1b.png|left|200px]]
<!--
<!--
Line 9: Line 10:
{{STRUCTURE_1x1b| PDB=1x1b | SCENE= }}
{{STRUCTURE_1x1b| PDB=1x1b | SCENE= }}
-
'''Crystal structure of BchU complexed with S-adenosyl-L-homocysteine'''
+
===Crystal structure of BchU complexed with S-adenosyl-L-homocysteine===
-
==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.
+
The line below this paragraph, {{ABSTRACT_PUBMED_16797589}}, adds the Publication Abstract to the page
 +
(as it appears on PubMed at http://www.pubmed.gov), where 16797589 is the PubMed ID number.
 +
-->
 +
{{ABSTRACT_PUBMED_16797589}}
==About this Structure==
==About this Structure==
Line 34: Line 38:
[[Category: Sah]]
[[Category: Sah]]
[[Category: Sam]]
[[Category: Sam]]
-
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 14:24:11 2008''
+
 
 +
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 09:07:06 2008''

Revision as of 06:07, 28 July 2008

Image:1x1b.png

Template:STRUCTURE 1x1b

Crystal structure of BchU complexed with S-adenosyl-L-homocysteine

Template:ABSTRACT PUBMED 16797589

About this Structure

1X1B 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

Page seeded by OCA on Mon Jul 28 09:07:06 2008

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1x1b"
Personal tools