1RZZ

PHOTOSYNTHETIC REACTION CENTER DOUBLE MUTANT FROM RHODOBACTER SPHAEROIDES WITH ASP L213 REPLACED WITH ASN AND ARG M233 REPLACED WITH CYS IN THE CHARGE-NEUTRAL DQAQB STATE (TETRAGONAL FORM)

Summary for 1RZZ

• Entry DOI: 10.2210/pdb1rzz/pdb
• Related: 1AIG 1AIJ 1RVJ 1RY5 1RZH 1S00
• Descriptor: Reaction center protein L chain, Reaction center protein M chain, Reaction center protein H chain, ... (10 entities in total)
• Functional Keywords: bacterial photosynthesis, rhodobacter sphaeroides, proton transfer pathway, revertant, integral membrane protein, photosynthesis
• Biological source: Rhodobacter sphaeroides; More
• Total number of polymer chains: 6
• Total formula weight: 204211.22

Authors

Xu, Q.,Axelrod, H.L.,Abresch, E.C.,Paddock, M.L.,Okamura, M.Y.,Feher, G. (deposition date: 2003-12-29, release date: 2004-04-13, Last modification date: 2023-08-23)

Primary citation

Xu, Q.,Axelrod, H.L.,Abresch, E.C.,Paddock, M.L.,Okamura, M.Y.,Feher, G.
X-Ray Structure Determination of Three Mutants of the Bacterial Photosynthetic Reaction Centers from Rb. sphaeroides; Altered Proton Transfer Pathways.
STRUCTURE, 12:703-715, 2004

PubMed Abstract: In the photosynthetic reaction center (RC) from Rhodobacter sphaeroides, the reduction of a bound quinone molecule Q(B) is coupled with proton uptake. When Asp-L213 is replaced by Asn, proton transfer is inhibited. Proton transfer was restored by two second-site revertant mutations, Arg-M233-->Cys and Arg-H177-->His. Kinetic effects of Cd(2+) on proton transfer showed that the entry point in revertant RCs to be the same as in the native RC. The structures of the parental and two revertant RCs were determined at resolutions of 2.10, 1.80, and 2.75 A. From the structures, we were able to delineate alternate proton transfer pathways in the revertants. The main changes occur near Glu-H173, which allow it to substitute for the missing Asp-L213. The electrostatic changes near Glu-H173 cause it to be a good proton donor and acceptor, and the structural changes create a cavity which accommodates water molecules that connect Glu-H173 to other proton transfer components.

PubMed: 15062092
DOI: 10.1016/j.str.2004.03.001

Experimental method

X-RAY DIFFRACTION (2.4 Å)