Outer membrane β-barrel proteins differ from α-helical inner membrane proteins 
in lipid environment, secondary structure, and the proposed processes of folding 
and insertion. It is reasonable to expect that outer membrane proteins may 
contain primary sequence information specific for their folding and insertion 
behavior. In previous work, a depth-dependent insertion potential, E(z) , was 
derived for α-helical inner membrane proteins. We have generated an equivalent 
potential for TM β-barrel proteins. The similarities and differences between 
these two potentials provide insight into unique aspects of the folding and 
insertion of β-barrel membrane proteins. This potential can predict orientation 
within the membrane and identify functional residues involved in intermolecular 
interactions.