2XTQ

Structure of the P107A Colicin M mutant from E. coli

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.31 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.240 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history. 

Literature

Activation of Colicin M by the Fkpa Prolyl Cis- Trans Isomerase/Chaperone.

Helbig, S., Patzer, S.I., Schiene-Fischer, C., Zeth, K., Braun, V.

(2011) J.Biol.Chem. 286: 6280

  • DOI: 10.1074/jbc.M110.165274
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    • Colicin M (Cma) is specifically imported into the periplasm of Escherichia coli and kills the cells. Killing depends on the periplasmic peptidyl prolyl cis-trans isomerase/chaperone FkpA. To identify the Cma prolyl bonds targeted by FkpA, we replaced ...

    Colicin M (Cma) is specifically imported into the periplasm of Escherichia coli and kills the cells. Killing depends on the periplasmic peptidyl prolyl cis-trans isomerase/chaperone FkpA. To identify the Cma prolyl bonds targeted by FkpA, we replaced the 15 proline residues individually with alanine. Seven mutant proteins were fully active; Cma(P129A), Cma(P176A), and Cma(P260A) displayed 1%, and Cma(P107A) displayed 10% of the wild-type activity. Cma(P107A), Cma(P129A), and Cma(P260A), but not Cma(P176A), killed cells after entering the periplasm via osmotic shock, indicating that the former mutants were translocation-deficient; Cma(P129A) did not bind to the FhuA outer membrane receptor. The crystal structures of Cma and Cma(P176A) were identical, excluding inactivation of the activity domain located far from Pro-176. In a new peptidyl prolyl cis-trans isomerase assay, FkpA isomerized the Cma prolyl bond in peptide Phe-Pro-176 at a high rate, but Lys-Pro-107 and Leu-Pro-260 isomerized at only <10% of that rate. The four mutant proteins secreted into the periplasm via a fused signal sequence were toxic but much less than wild-type Cma. Wild-type and mutant Cma proteins secreted or translocated across the outer membrane by energy-coupled import or unspecific osmotic shock were only active in the presence of FkpA. We propose that Cma unfolds during transfer across the outer or cytoplasmic membrane and refolds to the active form in the periplasm assisted by FkpA. Weak refolding of Cma(P176A) would explain its low activity in all assays. Of the four proline residues identified as being important for Cma activity, Phe-Pro-176 is most likely targeted by FkpA.

    Organizational Affiliation: 

    Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
COLICIN-M
A, B, C, D, E, F, G, H
271Escherichia coliMutation(s): 1 
Gene Names: cma
Find proteins for P05820 (Escherichia coli)
Go to UniProtKB:  P05820
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.31 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.240 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 52.852α = 87.59
b = 63.114β = 82.17
c = 189.340γ = 65.65
Software Package:
Software NamePurpose
MOLREPphasing
REFMACrefinement
XDSdata reduction
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-12-22
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2018-06-20
    Type: Advisory, Data collection, Derived calculations