This family consists of several bacterial proteins which are homologous to the oligogalacturonate-specific porin protein KdgM from Erwinia chrysanthemi. The phytopathogenic Gram-negative bacteria Erwinia chrysanthemi secretes pectinases, which are able to degrade the pectic polymers of plant cell walls, and uses the degradation products as a carbon source for growth. KdgM is a major outer membrane protein, whose synthesis is strongly induced in the presence of pectic derivatives. KdgM behaves like a voltage-dependent porin that is slightly selective for anions and that exhibits fast block in the presence of trigalacturonate. In contrast to most porins, KdgM seems to be monomeric.