9K3Q | pdb_00009k3q

Cryo-EM structure of the Rhodospirillum rubrum RC-LH1 complex


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.02 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation 3D Report Full Report

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Literature

Characterization of the Structure and Function of the Photosynthetic RC-LH1 Core Supercomplex From Rhodospirillum rubrum.

Christianson, B.Liu, Z.Zhang, Y.Wang, C.Gardner, A.M.Zhang, Y.Z.Wang, P.Liu, L.N.

(2025) Physiol Plant 177: e70275-e70275

  • DOI: https://doi.org/10.1111/ppl.70275
  • Primary Citation Related Structures: 
    9K3Q

  • PubMed Abstract: 

    Photosynthetic reaction center-light harvesting 1 (RC-LH1) core supercomplexes are essential for energy capture and electron transport in purple bacteria. Rhodospirillum rubrum, a model organism for bacterial photosynthesis, features an RC-LH1 architecture with a closed LH1 ring and lacks the peripheral LH2 antenna in the photosynthetic membranes. How this unique RC-LH1 supercomplex performs energy transfer and quinone transport remains unclear. Here, we characterized both the structural and functional properties of Rsp. rubrum RC-LH1 supercomplex using cryo-electron microscopy (cryo-EM), transient absorption (TA) spectroscopy, and cytochrome c 2 oxidation assays. Cryo-EM of the RC-LH1 monomeric structure revealed a closed LH1 ring of 16 αβ-polypeptides encircling the RC, with weaker RC-LH1 interactions than other RC-LH1 structures reported. TA spectra and cytochrome c 2 oxidation assays showed that Rsp. rubrum RC-LH1 monomer with a closed LH1 ring exhibits slower and more distributed excitation energy transfer (EET) kinetics from LH1 to RC and slower electron transport rates than Rba. sphaeroides RC-LH1 monomer with a large opening in the LH1 ring. Our findings provide insight into the unique architecture and spectroscopic properties of Rsp. rubrum RC-LH1 supercomplex. This study enhances our understanding of bacterial photosynthetic mechanisms and lays the foundation for bioengineering applications in artificial photosynthetic systems.


  • Organizational Affiliation
    • Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK.

Macromolecule Content 

  • Total Structure Weight: 300.81 kDa 
  • Atom Count: 21,510 
  • Modeled Residue Count: 2,212 
  • Deposited Residue Count: 2,212 
  • Unique protein chains: 5

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
Light-harvesting protein B-870 beta chain44Rhodospirillum rubrumMutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for P0C190 (Rhodospirillum rubrum)
Explore P0C190 
Go to UniProtKB:  P0C190
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0C190
Sequence Annotations
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Reference Sequence
Find similar proteins by:|  3D Structure
Entity ID: 2
MoleculeChains  Sequence LengthOrganismDetailsImage
Light-harvesting protein B-870 alpha chain45Rhodospirillum rubrumMutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for P02947 (Rhodospirillum rubrum)
Explore P02947 
Go to UniProtKB:  P02947
Entity Groups
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UniProt GroupP02947
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Reference Sequence
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Entity ID: 3
MoleculeChains  Sequence LengthOrganismDetailsImage
Photoreaction center protein HO [auth H]255Rhodospirillum rubrumMutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for Q7M149 (Rhodospirillum rubrum)
Explore Q7M149 
Go to UniProtKB:  Q7M149
Entity Groups
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UniProt GroupQ7M149
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Reference Sequence
Find similar proteins by:|  3D Structure
Entity ID: 4
MoleculeChains  Sequence LengthOrganismDetailsImage
Reaction center protein L chainS [auth L]274Rhodospirillum rubrumMutation(s): 0 
Gene Names: pufL
Membrane Entity: Yes 
UniProt
Find proteins for P10717 (Rhodospirillum rubrum)
Explore P10717 
Go to UniProtKB:  P10717
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UniProt GroupP10717
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Reference Sequence
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Entity ID: 5
MoleculeChains  Sequence LengthOrganismDetailsImage
Reaction center protein M chainT [auth M]259Rhodospirillum rubrumMutation(s): 0 
Gene Names: Rru_A2974
Membrane Entity: Yes 
UniProt
Find proteins for P10718 (Rhodospirillum rubrum)
Explore P10718 
Go to UniProtKB:  P10718
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UniProt GroupP10718
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Reference Sequence

Small Molecules

Ligands 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
07D
(Subject of Investigation/LOI)

Query on 07D



Download:Ideal Coordinates CCD File
AB [auth F]
AC [auth S]
BB [auth G]
BC [auth T]
CB [auth H]
AB [auth F],
AC [auth S],
BB [auth G],
BC [auth T],
CB [auth H],
DC [auth U],
EC [auth V],
FB [auth I],
GB [auth J],
GC [auth W],
HC [auth X],
IB [auth K],
JA [auth 1],
JC [auth Y],
KC [auth Z],
LA [auth 2],
LB [auth L],
MB [auth L],
MC [auth d],
NA [auth 3],
OA [auth 4],
OC [auth m],
QA [auth 5],
QB [auth M],
QC [auth n],
RA [auth 6],
RB [auth M],
TA [auth 7],
TB [auth N],
UA [auth 8],
VB [auth O],
WA [auth 9],
XA [auth A],
XB [auth Q],
YA [auth D],
YB [auth R],
ZA [auth E]
Trans-Geranyl BACTERIOCHLOROPHYLL A
C55 H64 Mg N4 O6
ZBSZXIUSELHDGQ-POZHEDQMSA-M
BPH
(Subject of Investigation/LOI)

Query on BPH



Download:Ideal Coordinates CCD File
JB [auth L],
OB [auth M]
BACTERIOPHEOPHYTIN A
C55 H76 N4 O6
KWOZSBGNAHVCKG-SZQBJALDSA-N
U10
(Subject of Investigation/LOI)

Query on U10



Download:Ideal Coordinates CCD File
KB [auth L],
NB [auth L],
PB [auth M]
UBIQUINONE-10
C59 H90 O4
ACTIUHUUMQJHFO-UPTCCGCDSA-N
CRT

Query on CRT



Download:Ideal Coordinates CCD File
CC [auth U]
EB [auth I]
FC [auth W]
HB [auth K]
IC [auth Y]
CC [auth U],
EB [auth I],
FC [auth W],
HB [auth K],
IC [auth Y],
KA [auth 1],
LC [auth d],
MA [auth 3],
NC [auth m],
PA [auth 5],
PC [auth n],
SA [auth 7],
SB [auth M],
UB [auth O],
VA [auth 9],
WB [auth Q],
ZB [auth S]
SPIRILLOXANTHIN
C42 H60 O2
VAZQBTJCYODOSV-RISZBRKMSA-N
FE

Query on FE



Download:Ideal Coordinates CCD File
DB [auth H]FE (III) ION
Fe
VTLYFUHAOXGGBS-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.02 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion
MODEL REFINEMENTPHENIX1.20.1_4487:

Structure Validation

View Full Validation Report



Entry History 

& Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Royal SocietyUnited Kingdom--

Revision History  (Full details and data files)

  • Version 1.0: 2024-12-04
    Type: Initial release
  • Version 1.1: 2026-06-17
    Changes: Data collection, Database references