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X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
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Structural insights into regulated intramembrane proteolysis by the positive alginate regulator MucP from Pseudomonas

Xiaorui Lou1, Shanshan Li1, Yanan Wang1

  • 1College of Life Sciences, State Key Laboratory of Medicinal Chemical Biology, Nankai International Advanced Research Institute (Shenzhen Futian), Nankai University, Tianjin 300071, China.

Biochemical and Biophysical Research Communications
|November 20, 2024
PubMed

Insights

Regulated intramembrane proteolysis involves sequential protease cleavage. In Pseudomonas aeruginosa, MucP (Site-2 protease) cleaves MucA after AlgW (Site-1 protease), impacting biofilm formation.

Area of Science:

  • Microbiology
  • Structural Biology
  • Biochemistry

Background:

  • Regulated intramembrane proteolysis (RIP) is a conserved mechanism for protein processing.
  • The MucABCD system in Pseudomonas aeruginosa regulates the anti-sigma factor MucA, controlling alginate production.
  • MucA is cleaved by Site-1 protease AlgW and Site-2 protease MucP.

Purpose of the Study:

  • To elucidate the structural basis of MucP's function in regulated intramembrane proteolysis.
  • To understand the interaction between MucP and its substrate MucA.

Main Methods:

  • High-resolution crystal structure determination of MucP PDZ1 and PDZ2 domains.
  • Structural and binding analyses of MucP-MucA interactions.
  • Phenotypic analysis of Pseudomonas aeruginosa strains with mutations in mucP and algW.

Main Results:

  • Crystal structures revealed MucP PDZ2 binds the C-terminal Ala136 of MucA post-AlgW cleavage.
  • The PDZ1 domain's binding groove is blocked by an alpha-helix.
  • MucP and AlgW are crucial for Pseudomonas aeruginosa biofilm formation.

Conclusions:

  • MucP functions as a Site-2 protease, recognizing the C-terminus of MucA after Site-1 cleavage.
  • The structural insights into MucP-MucA interaction provide a basis for understanding RIP.
  • MucP is essential for Pseudomonas aeruginosa virulence, specifically biofilm formation.
Keywords:
Alginate biosynthesisMucPPDZ domainPseudomonas aeruginosaRegulated intramembrane proteolysis

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