PREDICTION OF THE GENERAL STRUCTURE OF OMPF AND PHOE FROM THE SEQUENCE AND STRUCTURE OF PORIN FROM RHODOBACTER-CAPSULATUS - ORIENTATION OF PORIN IN THE MEMBRANE

By comparing the hydrophilicity profiles and sequences of porin from Rhodobacter capsulatus with those of OmpF and PhoE from Escherichia coli, a set of insertions and deletions for alignment of the sequences has been deduced. With this alignment a similar folding of OmpF and PhoE has been predicted as found by X-ray structure analysis of porin from Rhodobacter capsulatus. Furthermore, the orientation of the porin trimer in the outer membrane was inferred from topological data on PhoE. According to this result a single channel of approx. 30-angstrom diameter starts at the outer surface. Near the middle of the outer membrane bilayer this channel branches out into three separate channels, each running within a single porin monomer to the periplasmic surface.