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Title: Identification of protein W, the elusive sixth subunit of the Rhodopseudomonas palustris reaction center-light harvesting 1 core complex

Abstract

The X-ray crystal structure of the Rhodopseudomonas ( Rps.) palustris reaction center-light harvesting 1 (RC-LH1) core complex revealed the presence of a sixth protein component, variably referred to in the literature as helix W, subunit W or protein W. The position of this protein prevents closure of the LH1 ring, possibly to allow diffusion of ubiquinone/ubiquinol between the RC and the cytochrome bc 1 complex in analogous fashion to the well-studied PufX protein from Rhodobacter sphaeroides. The identity and function of helix W have remained unknown for over 13 years; here we use a combination of biochemistry, mass spectrometry, molecular genetics and electron microscopy to identify this protein as RPA4402 in Rps. palustris CGA009. Protein W shares key conserved sequence features with PufX homologs, and although a deletion mutant was able to grow under photosynthetic conditions with no discernible phenotype, we demonstrate that a tagged version of protein W pulls down the RC-LH1 complex. Protein W is not encoded in the photosynthesis gene cluster and our data indicate that only approximately 10% of wild-type Rps. palustris core complexes contain this non-essential subunit; functional and evolutionary consequences of this observation are discussed. The ability to purify uniform RC-LH1 and RC-LH1- proteinmore » W preparations will also be beneficial for future structural studies of these bacterial core complexes.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. Univ. of Sheffield (United Kingdom)
Publication Date:
Research Org.:
Washington Univ., St. Louis, MO (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1437760
Alternate Identifier(s):
OSTI ID: 1511836
Grant/Contract Number:  
SC0001035
Resource Type:
Journal Article: Published Article
Journal Name:
Biochimica et Biophysica Acta - Bioenergetics
Additional Journal Information:
Journal Volume: 1859; Journal Issue: 2; Journal ID: ISSN 0005-2728
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; Photosynthesis; Rhodopseudomonas palustris; Reaction center-light harvesting 1 (RC-LH1) core complex; Helix W; RPA4402; PufX

Citation Formats

Jackson, Philip J., Hitchcock, Andrew, Swainsbury, David J. K., Qian, Pu, Martin, Elizabeth C., Farmer, David A., Dickman, Mark J., Canniffe, Daniel P., and Hunter, C. Neil. Identification of protein W, the elusive sixth subunit of the Rhodopseudomonas palustris reaction center-light harvesting 1 core complex. United States: N. p., 2017. Web. doi:10.1016/j.bbabio.2017.11.001.
Jackson, Philip J., Hitchcock, Andrew, Swainsbury, David J. K., Qian, Pu, Martin, Elizabeth C., Farmer, David A., Dickman, Mark J., Canniffe, Daniel P., & Hunter, C. Neil. Identification of protein W, the elusive sixth subunit of the Rhodopseudomonas palustris reaction center-light harvesting 1 core complex. United States. doi:10.1016/j.bbabio.2017.11.001.
Jackson, Philip J., Hitchcock, Andrew, Swainsbury, David J. K., Qian, Pu, Martin, Elizabeth C., Farmer, David A., Dickman, Mark J., Canniffe, Daniel P., and Hunter, C. Neil. Tue . "Identification of protein W, the elusive sixth subunit of the Rhodopseudomonas palustris reaction center-light harvesting 1 core complex". United States. doi:10.1016/j.bbabio.2017.11.001.
@article{osti_1437760,
title = {Identification of protein W, the elusive sixth subunit of the Rhodopseudomonas palustris reaction center-light harvesting 1 core complex},
author = {Jackson, Philip J. and Hitchcock, Andrew and Swainsbury, David J. K. and Qian, Pu and Martin, Elizabeth C. and Farmer, David A. and Dickman, Mark J. and Canniffe, Daniel P. and Hunter, C. Neil},
abstractNote = {The X-ray crystal structure of the Rhodopseudomonas (Rps.) palustris reaction center-light harvesting 1 (RC-LH1) core complex revealed the presence of a sixth protein component, variably referred to in the literature as helix W, subunit W or protein W. The position of this protein prevents closure of the LH1 ring, possibly to allow diffusion of ubiquinone/ubiquinol between the RC and the cytochrome bc1 complex in analogous fashion to the well-studied PufX protein from Rhodobacter sphaeroides. The identity and function of helix W have remained unknown for over 13 years; here we use a combination of biochemistry, mass spectrometry, molecular genetics and electron microscopy to identify this protein as RPA4402 in Rps. palustris CGA009. Protein W shares key conserved sequence features with PufX homologs, and although a deletion mutant was able to grow under photosynthetic conditions with no discernible phenotype, we demonstrate that a tagged version of protein W pulls down the RC-LH1 complex. Protein W is not encoded in the photosynthesis gene cluster and our data indicate that only approximately 10% of wild-type Rps. palustris core complexes contain this non-essential subunit; functional and evolutionary consequences of this observation are discussed. The ability to purify uniform RC-LH1 and RC-LH1- protein W preparations will also be beneficial for future structural studies of these bacterial core complexes.},
doi = {10.1016/j.bbabio.2017.11.001},
journal = {Biochimica et Biophysica Acta - Bioenergetics},
issn = {0005-2728},
number = 2,
volume = 1859,
place = {United States},
year = {2017},
month = {11}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.bbabio.2017.11.001

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