Outer membrane protein C (OmpC)

Outer membrane protein C (OmpC) is a major porin protein located in the outer membrane of Gram-negative bacteria, most notably Escherichia coli (UniProt: P0EB06). It functions as a trimeric, water-filled channel that facilitates the passive diffusion of small hydrophilic molecules, such as ions, nutrients, and various classes of antibiotics, into the periplasmic space (PubMed: 25239701). OmpC expression is tightly regulated by environmental osmolarity, typically increasing in high-osmotic conditions like those found in the human gut (PubMed: 10896611). Clinically, OmpC is a critical factor in antimicrobial resistance, as bacteria often reduce its expression or mutate the pore structure to limit the entry of drugs like beta-lactams and fluoroquinolones (PubMed: 19154492). Additionally, OmpC serves as a significant immunogen; the detection of anti-OmpC antibodies in human serum is used as a diagnostic and prognostic biomarker for Crohn's disease, often correlating with more severe clinical outcomes (PubMed: 11246365). The protein is also a target for bacteriophage attachment and is being explored in the context of novel antibacterial strategies and phage therapy.

Other names

Porin COuter membrane porin COmpC porin

Facilitates the passive diffusion of hydrophilic antibiotics across the bacterial outer membrane into the periplasmic space.