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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:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Washington Univ., St. Louis, MO (United States); Energy Frontier Research Centers (EFRC) (United States). Photosynthetic Antenna Research Center (PARC)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
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 Name: Biochimica et Biophysica Acta - Bioenergetics Journal Volume: 1859 Journal Issue: 2; Journal ID: ISSN 0005-2728
Publisher:
Elsevier
Country of Publication:
Netherlands
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. Netherlands: N. p., 2018. 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. Netherlands. https://doi.org/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. Thu . "Identification of protein W, the elusive sixth subunit of the Rhodopseudomonas palustris reaction center-light harvesting 1 core complex". Netherlands. https://doi.org/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},
url = {https://www.osti.gov/biblio/1437760}, journal = {Biochimica et Biophysica Acta - Bioenergetics},
issn = {0005-2728},
number = 2,
volume = 1859,
place = {Netherlands},
year = {2018},
month = {2}
}

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

Figures / Tables:

Fig. 1 Fig. 1: X-ray crystal structure of the Rps. palustris core complex showing the position of the W subunit. This figure was made using the data from the 4.8 Å resolution RC-LH1 structure of Roszak et al. (PDB ID: 1PYH). (A) Schematic model of the RC-LH1 core complex viewed perpendicular tomore » the membrane plane along the pseudo-twofold-axis of the RC and (B) as a narrow section viewed parallel to the membrane plane with the cytoplasmic face at the bottom. Transmembrane helices are depicted as ribbons and bacteriochlorophylls/bacteriopheophytins are represented as their respective macrocycles and are coloured green. Core complex subunits are shown in red, LH1 α subunits in blue, LH1 β subunits in white, and the W subunit in yellow.« less

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Works referencing / citing this record:

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journal, February 2020


    Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.