The structure of porin from Paracoccus denitrificans at 3.1 angstrom resolution

The crystal structure of a non-specific porin from Paracoccus denitrificans at 3.1 Angstrom resolution has been solved by molecular replacement using the porin from Rhodopseudomonas blastica as the search model. Paracoccus porin is very similar to other non-specific porins of known structure: a trimer of 16 stranded beta-barrels each with a central pore constricted by a long extracellular loop folding back against the barrel wall. The distinctive distribution of charged residues of this non-specific porin contributes to understanding the relation between structure and ion selectivity. (C) 1997 Federation of European Biochemical Societies.