skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Monomeric RC-LH1 core complexes retard LH2 assembly and intracytoplasmic membrane formation in PufX-minus mutants of Rhodobacter sphaeroides

Abstract

In the model photosynthetic bacterium Rhodobacter sphaeroides domains of light-harvesting 2 (LH2) complexes surround and interconnect dimeric reaction centre–light-harvesting 1–PufX (RC–LH1–PufX) ‘core’ complexes, forming extensive networks for energy transfer and trapping. These complexes are housed in spherical intracytoplasmic membranes (ICMs), which are assembled in a stepwise process where biosynthesis of core complexes tends to dominate the early stages of membrane invagination. The kinetics of LH2 assembly were measured in PufX mutants that assemble monomeric core complexes, as a consequence of either a twelve-residue N-terminal truncation of PufX (PufXΔ12) or the complete removal of PufX (PufX -). Lower rates of LH2 assembly and retarded maturation of membrane invagination were observed for the larger and less curved ICM from the PufX - mutant, consistent with the proposition that local membrane curvature, initiated by arrays of bent RC–LH1–PufX dimers, creates a favourable environment for stable assembly of LH2 complexes. Transmission electron microscopy and high-resolution atomic force microscopy were used to examine ICM morphology and membrane protein organisation in these mutants. Some partitioning of core and LH2 complexes was observed in PufX - membranes, resulting in locally ordered clusters of monomeric RC–LH1 complexes. The distribution of core and LH2 complexes in the three typesmore » of membrane examined is consistent with previous models of membrane curvature and domain formation (Frese et al., 2008), which demonstrated that a combination of crowding and asymmetries in sizes and shapes of membrane protein complexes drives membrane organisation.« less

Authors:
 [1];  [1];  [1];  [1];  [1]
  1. University of Sheffield (United Kingdom)
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC); Photosynthetic Antenna Research Center (PARC)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1065600
DOE Contract Number:  
SC0001035
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochimica et Biophysica Acta - Bioenergetics; Journal Volume: 1807; Journal Issue: 9; Related Information: PARC partners with Washington University in St. Louis (lead); University of California, Riverside; University of Glasgow, UK; Los Alamos National Laboratory; University of New Mexico; New Mexico Corsortium; North Carolina State University; Northwestern University; Oak Ridge National Laboratory; University of Pennsylvania; Sandia National Laboratories; University of Sheffield, UK
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; solar (fuels), photosynthesis (natural and artificial), biofuels (including algae and biomass), bio-inspired, charge transport, membrane, synthesis (novel materials), synthesis (self-assembly)

Citation Formats

Adams, Peter G., Mothersole, David J., Ng, Irene W., Olsen, John D., and Hunter, C. Neil. Monomeric RC-LH1 core complexes retard LH2 assembly and intracytoplasmic membrane formation in PufX-minus mutants of Rhodobacter sphaeroides. United States: N. p., 2011. Web. doi:10.1016/j.bbabio.2011.05.019.
Adams, Peter G., Mothersole, David J., Ng, Irene W., Olsen, John D., & Hunter, C. Neil. Monomeric RC-LH1 core complexes retard LH2 assembly and intracytoplasmic membrane formation in PufX-minus mutants of Rhodobacter sphaeroides. United States. doi:10.1016/j.bbabio.2011.05.019.
Adams, Peter G., Mothersole, David J., Ng, Irene W., Olsen, John D., and Hunter, C. Neil. Sat . "Monomeric RC-LH1 core complexes retard LH2 assembly and intracytoplasmic membrane formation in PufX-minus mutants of Rhodobacter sphaeroides". United States. doi:10.1016/j.bbabio.2011.05.019.
@article{osti_1065600,
title = {Monomeric RC-LH1 core complexes retard LH2 assembly and intracytoplasmic membrane formation in PufX-minus mutants of Rhodobacter sphaeroides},
author = {Adams, Peter G. and Mothersole, David J. and Ng, Irene W. and Olsen, John D. and Hunter, C. Neil},
abstractNote = {In the model photosynthetic bacterium Rhodobacter sphaeroides domains of light-harvesting 2 (LH2) complexes surround and interconnect dimeric reaction centre–light-harvesting 1–PufX (RC–LH1–PufX) ‘core’ complexes, forming extensive networks for energy transfer and trapping. These complexes are housed in spherical intracytoplasmic membranes (ICMs), which are assembled in a stepwise process where biosynthesis of core complexes tends to dominate the early stages of membrane invagination. The kinetics of LH2 assembly were measured in PufX mutants that assemble monomeric core complexes, as a consequence of either a twelve-residue N-terminal truncation of PufX (PufXΔ12) or the complete removal of PufX (PufX-). Lower rates of LH2 assembly and retarded maturation of membrane invagination were observed for the larger and less curved ICM from the PufX- mutant, consistent with the proposition that local membrane curvature, initiated by arrays of bent RC–LH1–PufX dimers, creates a favourable environment for stable assembly of LH2 complexes. Transmission electron microscopy and high-resolution atomic force microscopy were used to examine ICM morphology and membrane protein organisation in these mutants. Some partitioning of core and LH2 complexes was observed in PufX- membranes, resulting in locally ordered clusters of monomeric RC–LH1 complexes. The distribution of core and LH2 complexes in the three types of membrane examined is consistent with previous models of membrane curvature and domain formation (Frese et al., 2008), which demonstrated that a combination of crowding and asymmetries in sizes and shapes of membrane protein complexes drives membrane organisation.},
doi = {10.1016/j.bbabio.2011.05.019},
journal = {Biochimica et Biophysica Acta - Bioenergetics},
number = 9,
volume = 1807,
place = {United States},
year = {Sat Jan 01 00:00:00 EST 2011},
month = {Sat Jan 01 00:00:00 EST 2011}
}