protein modulating permeability to antibiotic General Bacterial Porin (GBP) antibiotic_resistance ARO:3004277 General bacterial porins are a family of porins found in the outer membrane of Gram-negative bacteria. They catalyze the energy-independent transport of small molecules across the outer membranes of bacteria. Most of the porins of these family are homotrimeric and have variable selectivity, ranging from being cation-selective, anion-selective or selective for different compounds. The most well characterized members of this family are the OmpF and OmpC porins of Escherichia coli. This family is also known as the classical porins.