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Title: Genetic probes of structure/function relationships in the Q{sub B} binding site of the photosynthetic reaction center

Abstract

In photosynthetic reaction centers, a quinone molecule, Q{sub B}, is the terminal acceptor in light-induced electron transfer. The crystal structure of the reaction center implicates the protonatable amiho acid residues L212Glu and L213Asp in the binding of Q{sub B} to the reaction center and in proton transfer to the anionic forms of Q{sub B} generated by electron transfer from Q{sub A}. Here we report the construction of the double mutant L212Ala-L213Ala by site-specific mutagenesis, and the isolation and preliminary biophysical characterization of revertant and suppressor strains that have regained the ability to grow under photosynthetic conditions. Our results show that neither L212Glu nor L213Asp is essential for efficient light-induced electron or proton transfer in Rhodobacter capsulatus and that second-site mutations, located within the QB binding pocket or at a more distant site, can compensate for mutations at L212 and L213. Acquisition of a single negatively charged residue (at position L213, or on the other side of the binding pocket at position L225) or loss of a positively charged residue (at position M231) is sufficient to restore activity to the complex.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab., IL (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States); Public Health Service, Washington, DC (United States)
OSTI Identifier:
10148981
Report Number(s):
ANL/BIM/PP-71996
ON: DE94011490; CNN: Grant GM36598
DOE Contract Number:  
W-31109-ENG-38
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 25 Jun 1991
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 14 SOLAR ENERGY; PHOTOSYNTHETIC REACTION CENTERS; PROTEIN ENGINEERING; BIOCHEMICAL REACTION KINETICS; ELECTRON TRANSFER; UBIQUINONE; MEMBRANE PROTEINS; BIOELECTRICITY; SPECIES DIVERSITY; GENETIC ENGINEERING; AMINO ACID SEQUENCE; PROTEIN STRUCTURE; 550200; 140505; BIOCHEMISTRY; PHOTOCHEMICAL, PHOTOBIOLOGICAL, AND THERMOCHEMICAL CONVERSION

Citation Formats

Hanson, D K, Tiede, D M, Nance, S L, Chang, Chong-Hwan, and Schiffer, M. Genetic probes of structure/function relationships in the Q{sub B} binding site of the photosynthetic reaction center. United States: N. p., 1991. Web. doi:10.2172/10148981.
Hanson, D K, Tiede, D M, Nance, S L, Chang, Chong-Hwan, & Schiffer, M. Genetic probes of structure/function relationships in the Q{sub B} binding site of the photosynthetic reaction center. United States. doi:10.2172/10148981.
Hanson, D K, Tiede, D M, Nance, S L, Chang, Chong-Hwan, and Schiffer, M. Tue . "Genetic probes of structure/function relationships in the Q{sub B} binding site of the photosynthetic reaction center". United States. doi:10.2172/10148981. https://www.osti.gov/servlets/purl/10148981.
@article{osti_10148981,
title = {Genetic probes of structure/function relationships in the Q{sub B} binding site of the photosynthetic reaction center},
author = {Hanson, D K and Tiede, D M and Nance, S L and Chang, Chong-Hwan and Schiffer, M},
abstractNote = {In photosynthetic reaction centers, a quinone molecule, Q{sub B}, is the terminal acceptor in light-induced electron transfer. The crystal structure of the reaction center implicates the protonatable amiho acid residues L212Glu and L213Asp in the binding of Q{sub B} to the reaction center and in proton transfer to the anionic forms of Q{sub B} generated by electron transfer from Q{sub A}. Here we report the construction of the double mutant L212Ala-L213Ala by site-specific mutagenesis, and the isolation and preliminary biophysical characterization of revertant and suppressor strains that have regained the ability to grow under photosynthetic conditions. Our results show that neither L212Glu nor L213Asp is essential for efficient light-induced electron or proton transfer in Rhodobacter capsulatus and that second-site mutations, located within the QB binding pocket or at a more distant site, can compensate for mutations at L212 and L213. Acquisition of a single negatively charged residue (at position L213, or on the other side of the binding pocket at position L225) or loss of a positively charged residue (at position M231) is sufficient to restore activity to the complex.},
doi = {10.2172/10148981},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1991},
month = {6}
}