Porin protein (Porin)

Porins are beta-barrel transmembrane proteins found in the outer membrane of Gram-negative bacteria, mitochondria, and chloroplasts. Structurally, porins consist of anti-parallel beta strands that form a cylindrical barrel, with hydrophobic residues facing outward to interact with the lipid membrane and hydrophilic residues lining the aqueous pore. The channel allows passive diffusion of small hydrophilic molecules (ions, nutrients, metabolites, and antibiotics), playing key roles in cell permeability and nutritional exchange. In pathogens, specific porin subtypes are implicated in virulence and are essential for nutrient acquisition, host interaction, and antibiotic entry. Porin loss or modification is a major mechanism by which bacteria develop drug resistance, making porins important research and diagnostic targets in infectious disease and antimicrobial therapy. The "Porin A protein" label is not an exact standardized species/isoform, so detailed information should always specify the bacterial species and porin subtype.

Other names

Major porin proteinOmpF (Outer membrane protein F) (E. coli)OprF (P. aeruginosa)PorinOuter membrane porinPorin channel

Facilitate passive diffusion of antibiotics into bacteria (drug entry). Porin loss or modification leads to reduced drug entry and antibiotic resistance. Some drugs block porin function directly or induce conformational changes.