Structure of the N-terminal domain of Omp85 from the Thermophilic Cyanobacterium Thermosynechococcus elongatus

Experimental Data Snapshot

  • Resolution: 1.97 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.202 

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Omp85 from the Thermophilic Cyanobacterium Thermosynechococcus Elongatus Differs from Proteobacterial Omp85 in Structure and Domain Composition.

Arnold, T.Zeth, K.Linke, D.

(2010) J Biol Chem 285: 18003

  • DOI: https://doi.org/10.1074/jbc.M110.112516
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Omp85 proteins are essential proteins located in the bacterial outer membrane. They are involved in outer membrane biogenesis and assist outer membrane protein insertion and folding by an unknown mechanism. Homologous proteins exist in eukaryotes, where they mediate outer membrane assembly in organelles of endosymbiotic origin, the mitochondria and chloroplasts. We set out to explore the homologous relationship between cyanobacteria and chloroplasts, studying the Omp85 protein from the thermophilic cyanobacterium Thermosynechococcus elongatus. Using state-of-the art sequence analysis and clustering methods, we show how this protein is more closely related to its chloroplast homologue Toc75 than to proteobacterial Omp85, a finding supported by single channel conductance measurements. We have solved the structure of the periplasmic part of the protein to 1.97 A resolution, and we demonstrate that in contrast to Omp85 from Escherichia coli the protein has only three, not five, polypeptide transport-associated (POTRA) domains, which recognize substrates and generally interact with other proteins in bigger complexes. We model how these POTRA domains are attached to the outer membrane, based on the relationship of Omp85 to two-partner secretion system proteins, which we show and analyze. Finally, we discuss how Omp85 proteins with different numbers of POTRA domains evolved, and evolve to this day, to accomplish an increasing number of interactions with substrates and helper proteins.

  • Organizational Affiliation

    Department I, Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
TLR1789 PROTEINA [auth X]235Thermosynechococcus vestitusMutation(s): 0 
Membrane Entity: Yes 
Find proteins for Q8DI03 (Thermosynechococcus vestitus (strain NIES-2133 / IAM M-273 / BP-1))
Explore Q8DI03 
Go to UniProtKB:  Q8DI03
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8DI03
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.97 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.202 
  • Space Group: I 4 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 158.18α = 90
b = 158.18β = 90
c = 158.18γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-03-23
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2019-10-16
    Changes: Data collection, Experimental preparation, Other
  • Version 1.3: 2024-05-08
    Changes: Data collection, Database references