4KNF

Crystal structure of a blue-light absorbing proteorhodopsin double-mutant D97N/Q105L from HOT75


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.219 
  • R-Value Observed: 0.222 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Cross-protomer interaction with the photoactive site in oligomeric proteorhodopsin complexes.

Ran, T.Ozorowski, G.Gao, Y.Sineshchekov, O.A.Wang, W.Spudich, J.L.Luecke, H.

(2013) Acta Crystallogr D Biol Crystallogr 69: 1965-1980

  • DOI: 10.1107/S0907444913017575
  • Primary Citation of Related Structures:  
    4JQ6, 4KLY, 4KNF

  • PubMed Abstract: 
  • Proteorhodopsins (PRs), members of the microbial rhodopsin superfamily of seven-transmembrane-helix proteins that use retinal chromophores, comprise the largest subfamily of rhodopsins, yet very little structural information is available. PRs are ubiquitous throughout the biosphere and their genes have been sequenced in numerous species of bacteria ...

    Proteorhodopsins (PRs), members of the microbial rhodopsin superfamily of seven-transmembrane-helix proteins that use retinal chromophores, comprise the largest subfamily of rhodopsins, yet very little structural information is available. PRs are ubiquitous throughout the biosphere and their genes have been sequenced in numerous species of bacteria. They have been shown to exhibit ion-pumping activity like their archaeal homolog bacteriorhodopsin (BR). Here, the first crystal structure of a proteorhodopsin, that of a blue-light-absorbing proteorhodopsin (BPR) isolated from the Mediterranean Sea at a depth of 12 m (Med12BPR), is reported. Six molecules of Med12BPR form a doughnut-shaped C6 hexameric ring, unlike BR, which forms a trimer. Furthermore, the structures of two mutants of a related BPR isolated from the Pacific Ocean near Hawaii at a depth of 75 m (HOT75BPR), which show a C5 pentameric arrangement, are reported. In all three structures the retinal polyene chain is shifted towards helix C when compared with other microbial rhodopsins, and the putative proton-release group in BPR differs significantly from those of BR and xanthorhodopsin (XR). The most striking feature of proteorhodopsin is the position of the conserved active-site histidine (His75, also found in XR), which forms a hydrogen bond to the proton acceptor from the same molecule (Asp97) and also to Trp34 of a neighboring protomer. Trp34 may function by stabilizing His75 in a conformation that favors a deprotonated Asp97 in the dark state, and suggests cooperative behavior between protomers when the protein is in an oligomeric form. Mutation-induced alterations in proton transfers in the BPR photocycle in Escherichia coli cells provide evidence for a similar cross-protomer interaction of BPR in living cells and a functional role of the inter-protomer Trp34-His75 interaction in ion transport. Finally, Wat402, a key molecule responsible for proton translocation between the Schiff base and the proton acceptor in BR, appears to be absent in PR, suggesting that the ion-transfer mechanism may differ between PR and BR.


    Organizational Affiliation

    Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Blue-light absorbing proteorhodopsinA, B, C, D, E261gamma proteobacterium 'Hot 75m4Mutation(s): 2 
Membrane protein
Mpstruc
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Bacterial, Algal, Viral, and Unusual Rhodopsins
Protein: 
Proteorhodopsin (blue-light absorbing); HOT75BPR, D97N mutant
Find proteins for Q9AFF7 (Gamma-proteobacterium Hot 75m4)
Explore Q9AFF7 
Go to UniProtKB:  Q9AFF7
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.219 
  • R-Value Observed: 0.222 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 161.4α = 90
b = 168.9β = 90
c = 65.7γ = 90
Software Package:
Software NamePurpose
PHASERphasing
REFMACrefinement
XDSdata reduction
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-06-05
    Type: Initial release
  • Version 1.1: 2013-06-19
    Changes: Other
  • Version 1.2: 2013-10-23
    Changes: Database references