1RG5

Structure of the photosynthetic reaction centre from Rhodobacter sphaeroides carotenoidless strain R-26.1

Summary for 1RG5

• Entry DOI: 10.2210/pdb1rg5/pdb
• Related: 1rgn 1rqk 4rcr
• Descriptor: Reaction center protein L chain, LAURYL DIMETHYLAMINE-N-OXIDE, Reaction center protein M chain, ... (11 entities in total)
• Functional Keywords: photosynthesis, photosynthetic reaction center, carotenoidless mutant, carotenoid binding site, membrane protein
• Biological source: Rhodobacter sphaeroides; More
• Total number of polymer chains: 3
• Total formula weight: 104155.09

Authors

Roszak, A.W.,Hashimoto, H.,Gardiner, A.T.,Cogdell, R.J.,Isaacs, N.W. (deposition date: 2003-11-11, release date: 2004-04-27, Last modification date: 2024-02-14)

Primary citation

Roszak, A.W.,McKendrick, K.,Gardiner, A.T.,Mitchell, I.A.,Isaacs, N.W.,Cogdell, R.J.,Hashimoto, H.,Frank, H.A.
Protein Regulation of Carotenoid Binding: Gatekeeper and Locking Amino Acid Residues in Reaction Centers of Rhodobacter sphaeroides
STRUCTURE, 12:765-773, 2004

PubMed Abstract: X-ray diffraction was used to determine high-resolution structures of the reaction center (RC) complex from the carotenoidless mutant, Rb. sphaeroides R-26.1, without or reconstituted with carotenoids. The results are compared with the structure of the RC from a semiaerobically grown Rb. sphaeroides strain 2.4.1. The investigation reveals the structure of the carotenoid in the different protein preparations, the nature of its binding site, and a plausible mechanism by which the carotenoid is incorporated unidirectionally in its characteristic geometric configuration. The structural data suggest that the accessibility of the carotenoid to the binding site is controlled by a specific "gatekeeper" residue which allows the carotenoid to approach the binding site from only one direction. Carotenoid binding to the protein is secured by hydrogen bonding to a separate "locking" amino acid. The study reveals the specific molecular interactions that control how the carotenoid protects the photosynthetic apparatus against photo-induced oxidative destruction.

PubMed: 15130469
DOI: 10.1016/j.str.2004.02.037

Experimental method

X-RAY DIFFRACTION (2.5 Å)