Structural basis for the PufX-mediated dimerization of bacterial photosynthetic core complexes

Johan Busselez; Magali Cottevieille; Philippe Cuniasse; Francesca Gubellini; Nicolas Boisset; Daniel Lévy

doi:10.1016/j.str.2007.09.026

Structural basis for the PufX-mediated dimerization of bacterial photosynthetic core complexes

Structure. 2007 Dec;15(12):1674-83. doi: 10.1016/j.str.2007.09.026.

Authors

Johan Busselez¹, Magali Cottevieille, Philippe Cuniasse, Francesca Gubellini, Nicolas Boisset, Daniel Lévy

Affiliation

¹ Institut Curie, UMR-CNRS 168, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05, France.

PMID: 18073116
DOI: 10.1016/j.str.2007.09.026

Abstract

In Rhodobacter (Rba.) sphaeroides, the subunit PufX is involved in the dimeric organization of the core complex. Here, we report the 3D reconstruction at 12 A by cryoelectron microscopy of the core complex of Rba. veldkampii, a complex of approximately 300 kDa without symmetry. The core complex is monomeric and constituted by a light-harvesting complex 1 (LH1) ring surrounding a uniquely oriented reaction center (RC). The LH1 consists of 15 resolved alpha/beta heterodimers and is interrupted. Within the opening, PufX polypeptide is assigned at a position facing the Q(B) site of the RC. This core complex is different from a dissociated dimer of the core complex of Rba. sphaeroides revealing that PufX in Rba. veldkampii is unable to dimerize. The absence in PufX of Rba. veldkampii of a G(31)XXXG(35) dimerization motif highlights the transmembrane interactions between PufX subunits involved in the dimerization of the core complexes of Rhodobacter species.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Sequence
Bacterial Proteins / chemistry*
Cryoelectron Microscopy
Dimerization
Models, Molecular
Molecular Sequence Data
Photosynthesis*
Protein Conformation
Rhodobacter sphaeroides / chemistry*
Sequence Homology, Amino Acid

Substances

Bacterial Proteins