1k6l
From Proteopedia
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'''Photosynethetic Reaction Center from Rhodobacter sphaeroides''' | '''Photosynethetic Reaction Center from Rhodobacter sphaeroides''' | ||
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[[Category: Schiffer, M.]] | [[Category: Schiffer, M.]] | ||
[[Category: Wong, T N.]] | [[Category: Wong, T N.]] | ||
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| - | [[Category: | + | [[Category: Photosynthetic reaction center]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 22:22:09 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 19:22, 2 May 2008
Photosynethetic Reaction Center from Rhodobacter sphaeroides
Overview
We report on the unexpected structural changes caused by substitution of acidic amino acids in the Q(B) binding pocket of the bacterial photosynthetic reaction center by alanines. The mutations targeted key residues L212Glu and L213Asp of this transmembrane protein-cofactor complex. The amino acid substitutions in the L212Ala-L213Ala mutant reaction center ("AA") were known to affect the delivery of protons after the light-induced generation of Q(B)(-), which renders the AA strain incapable of photosynthetic growth. The AA structure not only revealed side chain rearrangements but also showed movement of the main chain segments that are contiguous with the mutation sites. The alanine substitutions caused an expansion of the cavity rather than its collapse. In addition, Q(B) is found mainly in the binding site that is proximal to the iron-ligand complex (closest to Q(A)) as opposed to its distal binding site (furthest from Q(A)) in the structure of the wild-type reaction center. The observed rearrangements in the structure of the AA reaction center establish a new balance between charged residues of an interactive network near Q(B). This structurally and electrostatically altered complex forms the basis for future understanding of the structural basis for proton transfer in active reaction centers which retain the alanine substitutions but carry a distant compensatory mutation.
About this Structure
1K6L is a Protein complex structure of sequences from Rhodobacter sphaeroides. Full crystallographic information is available from OCA.
Reference
The structure of a mutant photosynthetic reaction center shows unexpected changes in main chain orientations and quinone position., Pokkuluri PR, Laible PD, Deng YL, Wong TN, Hanson DK, Schiffer M, Biochemistry. 2002 May 14;41(19):5998-6007. PMID:11993994 Page seeded by OCA on Fri May 2 22:22:09 2008
