Many outer membrane proteins (OMPs) in Gram-negative bacteria possess known 
beta-barrel three-dimensional (3D) structures. These proteins, including 
channel-forming transmembrane porins, are diverse in sequence but exhibit common 
structural features. We here report computational analyses of six outer membrane 
proteins of known 3D structures with respect to (1) secondary structure, (2) 
hydropathy, and (3) amphipathicity. Using these characteristics, as well as the 
presence of an N-terminal targeting sequence, a program was developed allowing 
prediction of integral membrane beta-barrel proteins encoded within any 
completely sequenced prokaryotic genome. This program, termed the beta-barrel 
finder (BBF) program, was used to analyze the proteins encoded within the 
Escherichia coli genome. Out of 4290 sequences examined, 118 (2.8%) were 
retrieved. Of these, almost all known outer membrane proteins with established 
beta-barrel structures as well as many probable outer membrane proteins were 
identified. This program should be useful for predicting the occurrence of outer 
membrane proteins in bacteria with completely sequenced genomes.