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The patatin-like protein PlpD forms structurally dynamic homodimers in the Pseudomonas aeruginosa outer membrane

Sarah E Hanson1, Tyrone Dowdy2, Mioara Larion2

  • 1Genetics and Biochemistry Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.

Nature Communications
|May 23, 2024
PubMed

Insights

Pseudomonas aeruginosa PlpD, an outer membrane protein, challenges existing models by localizing its patatin-like domain to the periplasm and forming a homodimer. This protein exhibits unique structural dynamics, expanding our understanding of the Omp85 superfamily.

Area of Science:

  • Structural biology
  • Molecular microbiology
  • Protein biochemistry

Background:

  • Omp85 superfamily proteins feature a β-barrel domain and POTRA domains, crucial for protein assembly and translocation.
  • Pseudomonas aeruginosa PlpD, an Omp85 family member, has an N-terminal patatin-like (PL) domain.
  • Previously, it was assumed the PL domain is translocated across the outer membrane (OM) by the β-barrel domain.

Purpose of the Study:

  • To investigate the localization and structural characteristics of the PlpD patatin-like domain.
  • To challenge the established understanding of Omp85 protein function and structure.
  • To explore the structural diversity and evolutionary potential of the Omp85 superfamily.

Main Methods:

  • Biochemical and biophysical analyses were employed to study PlpD.
  • Localization studies determined the precise location of the PL domain.
  • Structural dynamics were investigated using advanced techniques.

Main Results:

  • The PlpD PL-domain is exclusively located in the periplasm, contrary to prior assumptions.
  • PlpD forms a homodimer, a characteristic not observed in previously studied Omp85 proteins.
  • A unique dynamic segment within the PL-domain undergoes transient strand-swapping with the β-barrel domain.

Conclusions:

  • The Omp85 superfamily exhibits greater structural diversity than previously recognized.
  • PlpD's unique structure and localization suggest novel functions within the Omp85 scaffold.
  • Evolution has utilized the Omp85 structure to generate diverse protein functions.

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