PDBsum entry 1k0t

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Electron transport PDB id
Protein chain
80 a.a. *
SF4 ×2
* Residue conservation analysis
PDB id:
Name: Electron transport
Title: Nmr solution structure of unbound, oxidized photosystem i su psac, containing [4fe-4s] clusters fa and fb
Structure: Psac subunit of photosystem i. Chain: a. Engineered: yes
Source: Synechococcus sp.. Organism_taxid: 32049. Strain: pcc 7002. Gene: psac. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.
NMR struc: 30 models
Authors: M.L.Antonkine,G.Liu,D.Bentrop,D.A.Bryant,I.Bertini,C.Luchina J.H.Golbeck,D.Stehlik
Key ref: M.L.Antonkine et al. (2002). Solution structure of the unbound, oxidized Photosystem I subunit PsaC, containing [4Fe-4S] clusters F(A) and F(B): a conformational change occurs upon binding to photosystem I. J Biol Inorg Chem, 7, 461-472. PubMed id: 11941504 DOI: 10.1007/s00775-001-0321-3
20-Sep-01     Release date:   05-Jun-02    
Go to PROCHECK summary

Protein chain
Pfam   ArchSchema ?
P31087  (PSAC_SYNP2) -  Photosystem I iron-sulfur center
81 a.a.
80 a.a.
Key:    PfamA domain  Secondary structure  CATH domain

 Enzyme reactions 
   Enzyme class: E.C.  - Photosystem I.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: Reduced plastocyanin + oxidized ferredoxin + light = oxidized plastocyanin + reduced ferredoxin
 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     membrane   4 terms 
  Biological process     oxidation-reduction process   3 terms 
  Biochemical function     electron carrier activity     5 terms  


DOI no: 10.1007/s00775-001-0321-3 J Biol Inorg Chem 7:461-472 (2002)
PubMed id: 11941504  
Solution structure of the unbound, oxidized Photosystem I subunit PsaC, containing [4Fe-4S] clusters F(A) and F(B): a conformational change occurs upon binding to photosystem I.
M.L.Antonkine, G.Liu, D.Bentrop, D.A.Bryant, I.Bertini, C.Luchinat, J.H.Golbeck, D.Stehlik.
This work presents the three-dimensional NMR solution structure of recombinant, oxidized, unbound PsaC from Synechococcus sp. PCC 7002. Constraints are derived from homo- and heteronuclear one-, two- and three-dimensional (1)H and (15)N NMR data. Significant differences are outlined between the unbound PsaC structure presented here and the available X-ray structure of bound PsaC as an integral part of the whole cyanobacterial PS I complex. These differences mainly concern the arrangement of the N- and C-termini with respect to the [4Fe-4S] core domain. In the NMR solution structure of PsaC the C-terminal region assumes a disordered helical conformation, and is clearly different from the extended coil conformation, which is one of the structural elements required to anchor PsaC to the PS I core heterodimer. In solution the N-terminus of PsaC is in contact with the pre-C-terminal region but slides in between the latter and the iron-sulfur core region of the protein. Together, these features result in a concerted movement of the N-terminus and pre-C-terminal region away from the F(A) binding site, accompanied by a bending of the N-terminus. In comparison, the same terminal regions are positioned much closer to F(A) and take up an anti-parallel beta-sheet arrangement in PsaC bound to PS I. The conformational changes between bound and unbound PsaC correlate with the differences reported earlier for the EPR spectra of reduced F(A) and F(B) in bound versus unbound PsaC. The observed different structural features in solution are highly relevant for unraveling the stepwise assembly process of the stromal PsaC, PsaD and PsaE subunits to the PS I core heterodimer. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at

Literature references that cite this PDB file's key reference

  PubMed id Reference
  20495604 J.Niklas, O.Gopta, B.Epel, W.Lubitz, and M.L.Antonkine (2010).
Investigation of the Stationary and Transient A(1) Radical in Trp --> Phe Mutants of Photosystem I.
  Appl Magn Reson, 38, 187-203.  
19757143 E.J.Boekema (2009).
Introduction to imaging methods in photosynthesis.
  Photosynth Res, 102, 107-109.  
18729093 M.S.Koay, M.L.Antonkine, W.Gärtner, and W.Lubitz (2008).
Modelling low-potential [Fe4S4] clusters in proteins.
  Chem Biodivers, 5, 1571-1587.  
17457690 M.Heinnickel, and J.H.Golbeck (2007).
Heliobacterial photosynthesis.
  Photosynth Res, 92, 35-53.  
12524325 J.H.Golbeck (2003).
The binding of cofactors to photosystem I analyzed by spectroscopic and mutagenic methods.
  Annu Rev Biophys Biomol Struct, 32, 237-256.  
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