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Protein D2 channel of the Pseudomonas aeruginosa outer membrane has a binding site for basic amino acids and peptides

J Trias1, H Nikaido

  • 1Department of Molecular and Cell Biology, University of California, Berkeley 94720.

The Journal of Biological Chemistry
|September 15, 1990
PubMed

Insights

Protein D2 in Pseudomonas aeruginosa facilitates imipenem entry. This outer membrane protein also transports basic amino acids and peptides, crucial for bacterial survival and potential therapeutic targets.

Area of Science:

  • Microbiology
  • Structural Biology
  • Biochemistry

Background:

  • Pseudomonas aeruginosa outer membrane protein D2 is a known channel for imipenem.
  • Understanding the specific binding and transport mechanisms of outer membrane proteins is vital for antimicrobial development.

Purpose of the Study:

  • To characterize the binding site of protein D2 and its role in solute transport.
  • To investigate the physiological significance of protein D2 in nutrient uptake.

Main Methods:

  • Competitive inhibition assays using various solutes to study imipenem diffusion.
  • Kinetic analysis of L- and D-lysine inhibition.
  • Transport assays comparing wild-type and D2-deficient mutant strains for tripeptide uptake.

Main Results:

  • Basic amino acids (lysine, arginine, histidine, ornithine) competitively inhibited imipenem diffusion.
  • L- and D-lysine exhibited competitive inhibition with specific Ki values.
  • Peptides containing lysine also inhibited imipenem transport.
  • Protein D2 facilitated the uptake of a lysine-containing tripeptide.

Conclusions:

  • Protein D2 possesses a binding site that interacts with basic amino acids and lysine-containing peptides.
  • Protein D2 plays a significant role in the outer membrane transport of basic amino acids and peptides in P. aeruginosa.
  • These findings highlight protein D2 as a potential target for modulating nutrient uptake and antimicrobial efficacy.

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