Protein Sequence Homologies between Portions of the L and M Subunits of Reaction Centers of Rhodopseudomonas capsulata and the 32 KD Herbicide-binding Polypeptide of Chloroplast Thylakoid Membranes and a Proposed Relation to Quinone-binding Sites

1984 ◽  
pp. 355-359 ◽  
Author(s):  
John E. Hearst ◽  
Kenneth Sauer
Keyword(s):  
Binding Sites ◽  
Protein Sequence ◽  
Thylakoid Membranes ◽  
Reaction Centers ◽  
Rhodopseudomonas Capsulata ◽  
Quinone Binding ◽  
Sequence Homologies ◽  
Herbicide Binding

Protein Sequence Homologies between Portions of the L and M Subunits of Reaction Centers of Rhodopseudomonas capsulata and the Qв-Protein of Chloroplast Thylakoid Membranes: a Proposed Relation to Quinone-Binding Sites

1984 ◽  
Vol 39 (5) ◽  
pp. 421-424 ◽  
Author(s):  
John E. Hearst ◽  
Kenneth Sauer
Keyword(s):  
Sequence Homology ◽  
Binding Sites ◽  
Protein Sequence ◽  
Thylakoid Membranes ◽  
Reaction Centers ◽  
Rhodopseudomonas Capsulata ◽  
Conserved Sequence ◽  
Quinone Binding ◽  
Sequence Homologies

Sequence homology has been found between the L and M subunits of Rhodopseudomonas capsulata reaction centers and the Qв-protein from all species thus far sequenced. The homology between the L subunit and the Qв-protein is contained in the sequence PFHMLG---F----AMHG-LV-S and is believed to have survived three billion years of evolution. A model is presented which associates quinone binding with this highly conserved sequence.

A Contact Site between the Two Reaction Center Polypeptides of Photosystem II Is Involved in Photoinhibition

1991 ◽  
Vol 46 (7-8) ◽  
pp. 557-562 ◽  
Author(s):  
A. Trebst
Keyword(s):  
Amino Acid ◽  
Photosystem Ii ◽  
Reaction Center ◽  
Binding Sites ◽  
Cleavage Site ◽  
Amino Acid Sequences ◽  
Contact Site ◽  
Quinone Binding ◽  
Herbicide Binding ◽  
Sensitive Site

Abstract A new contact site between the two reaction center polypeptides D 1 and D 2 of photosystem II close to arg 238 and arg 234 respectively is proposed. The amino acid sequences involved are between the 4 th transmembrane and a connecting parallel helix. The sequence includes a tryp­ sin sensitive site in both polypeptides, the likely cleavage site in the rapid turnover of the D 1 polypeptide and part of the herbicide binding site. The contact site is oriented towards both quinone binding sites Q A and Q B. A folding of the backbone of the amino acid sequences involved is proposed.

scholarly journals Structures of Rhodopseudomonas palustris RC-LH1 complexes with open or closed quinone channels

2021 ◽  
Vol 7 (3) ◽  
pp. eabe2631
Author(s):  
David J. K. Swainsbury ◽  
Pu Qian ◽  
Philip J. Jackson ◽  
Kaitlyn M. Faries ◽  
Dariusz M. Niedzwiedzki ◽  
...  
Keyword(s):  
Binding Sites ◽  
Rhodopseudomonas Palustris ◽  
Ring Closure ◽  
Light Harvesting Complex ◽  
The Core ◽  
Quinone Binding ◽  
Cryo Electron Microscopy ◽  
Unique Protein ◽  
Center Light ◽  
Resolution Structure

The reaction-center light-harvesting complex 1 (RC-LH1) is the core photosynthetic component in purple phototrophic bacteria. We present two cryo–electron microscopy structures of RC-LH1 complexes from Rhodopseudomonas palustris. A 2.65-Å resolution structure of the RC-LH114-W complex consists of an open 14-subunit LH1 ring surrounding the RC interrupted by protein-W, whereas the complex without protein-W at 2.80-Å resolution comprises an RC completely encircled by a closed, 16-subunit LH1 ring. Comparison of these structures provides insights into quinone dynamics within RC-LH1 complexes, including a previously unidentified conformational change upon quinone binding at the RC QB site, and the locations of accessory quinone binding sites that aid their delivery to the RC. The structurally unique protein-W prevents LH1 ring closure, creating a channel for accelerated quinone/quinol exchange.

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