PDBsum entry 4jcb

Photosynthesis

PDB id: 4jcb

Contents

Protein chains

(+ 8 more) 42 a.a.

57 a.a.

(+ 8 more) 48 a.a.

250 a.a.

281 a.a.

304 a.a.

Ligands

BCL ×32

BPH ×2

U10

PO4

Metals

FE2

PDB id:

4jcb

Name:

Photosynthesis

Title:

Rc-lh1-pufx dimer complex from rhodobacter sphaeroides

Structure:

Light-harvesting protein b-875 alpha chain. Chain: 5, t, v, x, 3, 7, d, f, 1, j, 2, n, p, z. Synonym: antenna pigment protein alpha chain, lh-1. Intrinsic membrane protein pufx. Chain: b. Light-harvesting protein b-875 beta chain. Chain: s, 9, o, q, 6, u, w, y, 4, 8, e, g, i, k. Synonym: antenna pigment protein beta chain, lh-3a. Reaction center protein h chain.

Source:

Rhodobacter sphaeroides. Organism_taxid: 1063. Other_details: photosynthetic membranes. Other_details: photosynthetic membranes

Resolution:

7.78Å R-factor: 0.229 R-free: 0.258

Authors:

P.Qian,M.Z.Papiz,P.J.Jackson,A.A.Brindley,I.W.Ng,J.D.Olsen, M.J.Dickman,P.A.Bullough,C.N.Hunter

Key ref:

P.Qian et al. (2013). Three-dimensional structure of the Rhodobacter sphaeroides RC-LH1-PufX complex: dimerization and quinone channels promoted by PufX. Biochemistry, 52, 7575-7585. PubMed id: 24131108 DOI: 10.1021/bi4011946

Date:

21-Feb-13 Release date: 30-Oct-13

Protein chains

P0C0X9  (LHA1_RHOSH) -  Light-harvesting protein B-875 alpha chain

Seq: 58 a.a.

Struc: 42 a.a.

Protein chain

P13402  (PUFX_RHOS4) -  Intrinsic membrane protein PufX

Seq: 82 a.a.

Struc: 57 a.a.

Protein chains

Q3J1A3  (LHB1_RHOS4) -  Light-harvesting protein B-875 beta chain

Seq: 49 a.a.

Struc: 48 a.a.

Protein chain

P0C0Y7  (RCEH_RHOSH) -  Reaction center protein H chain

Seq: 260 a.a.

Struc: 250 a.a.

Protein chain

P0C0Y8  (RCEL_RHOSH) -  Reaction center protein L chain

Seq: 282 a.a.

Struc: 281 a.a.

Protein chain

P0C0Y9  (RCEM_RHOSH) -  Reaction center protein M chain

Seq: 308 a.a.

Struc: 304 a.a.

DOI no: 10.1021/bi4011946

Biochemistry 52:7575-7585 (2013)

PubMed id: 24131108

Three-dimensional structure of the Rhodobacter sphaeroides RC-LH1-PufX complex: dimerization and quinone channels promoted by PufX.

P.Qian, M.Z.Papiz, P.J.Jackson, A.A.Brindley, I.W.Ng, J.D.Olsen, M.J.Dickman, P.A.Bullough, C.N.Hunter.

ABSTRACT

Reaction center-light harvesting 1 (RC-LH1) complexes are the fundamental units of bacterial photosynthesis, which use solar energy to power the reduction of quinone to quinol prior to the formation of the proton gradient that drives ATP synthesis. The dimeric RC-LH1-PufX complex of Rhodobacter sphaeroides is composed of 64 polypeptides and 128 cofactors, including 56 LH1 bacteriochlorophyll a (BChl a) molecules that surround and donate energy to the two RCs. The 3D structure was determined to 8 Å by X-ray crystallography, and a model was built with constraints provided by electron microscopy (EM), nuclear magnetic resonance (NMR), mass spectrometry (MS), and site-directed mutagenesis. Each half of the dimer complex consists of a RC surrounded by an array of 14 LH1 αβ subunits, with two BChls sandwiched between each αβ pair of transmembrane helices. The N- and C-terminal extrinsic domains of PufX promote dimerization by interacting with the corresponding domains of an LH1 β polypeptide from the other half of the RC-LH1-PufX complex. Close contacts between PufX, an LH1 αβ subunit, and the cytoplasmic domain of the RC-H subunit prevent the LH1 complex from encircling the RC and create a channel connecting the RC QB site to an opening in the LH1 ring, allowing Q/QH2 exchange with the external quinone pool. We also identified a channel that connects the two halves of the dimer, potentially forming a long-range pathway for quinone migration along rows of RC-LH1-PufX complexes in the membrane. The structure of the RC-LH1-PufX complex explains the crucial role played by PufX in dimer formation, and it shows how quinone traffic traverses the LH1 complex as it shuttles between the RC and the cytochrome bc1 complex.