Path of the polypeptide in bacteriorhodopsin.

Abstract
An attempt was made to fit the amino acid sequence of [Halobacterium halobium] bacteriorhodopsin to the 3-dimensional density map of the molecule. First, 7 segments of the sequence were selected as being probable transmembrane .alpha. helices. Then each of the 5040 possible ways of fitting these 7 segments into the 7 regions of helical density in the map were evaluated based on the criteria of connectivity of the nonhelical link regions, charge neutralization, and total scattering density per helix. A single model that may be experimentally tested emerged as the most probable.