PppA, a key regulatory component of T6SS in Pseudomonas aeruginosa

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.233 
  • R-Value Observed: 0.235 

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Crystal structure of PppA from Pseudomonas aeruginosa, a key regulatory component of type VI secretion systems.

Wu, Y.Gong, J.Liu, S.Li, D.Wu, Y.Zhang, X.Ren, Y.Xu, S.Sun, J.Wang, T.Lin, Q.Liu, L.

(2019) Biochem Biophys Res Commun 516: 196-201

  • DOI: https://doi.org/10.1016/j.bbrc.2019.06.020
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The Type VI secretion system (T6SS) is a membrane protein complex related to inter-bacterial competitions and host-pathogen interactions in Pseudomonas aeruginosa. The T6SS is regulated by a great variety of regulatory mechanisms at multiple levels, including post-translational modification with threonine phosphorylation mediated by Ser/Thr protein kinase PpkA and phosphatase PppA. The T6SS is activated by PpkA via Thr phosphorylation of Fha, and PppA can antagonize PpkA. PppA is a PP2C-family protein phosphatase and plays a key role in the disassembly and reassembly of T6SS organelles. Herein, we report the first crystal structure of PppA from Pseudomonas aeruginosa, which was determined at a resolution of 2.10 Å. The overall structure consists of a bacteria PPM structural core and a flexible flap subdomain. PppA harbors a catalytic pocket containing two manganese ions which correspond to the canonical dinuclear metal center of Ser/Thr protein phosphatases including the bacterial PPM phosphatases and human PP2C. The flexibility and the diversity of the sequence of flap subdomain across the homologues might provide clues for substrates specific recognition of phosphatases.

  • Organizational Affiliation

    School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055, China; Department of Biology, Southern University of Science and Technology, Shenzhen, 518055, China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
262Pseudomonas aeruginosaMutation(s): 0 
Find proteins for Q9I757 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Explore Q9I757 
Go to UniProtKB:  Q9I757
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9I757
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.233 
  • R-Value Observed: 0.235 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 50.541α = 90
b = 80.253β = 111.81
c = 59.084γ = 90
Software Package:
Software NamePurpose
d*TREKdata reduction
d*TREKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2019-06-26
    Type: Initial release
  • Version 1.1: 2019-07-03
    Changes: Data collection, Database references
  • Version 1.2: 2019-07-17
    Changes: Data collection, Database references
  • Version 1.3: 2023-11-22
    Changes: Data collection, Database references, Derived calculations, Refinement description