The hypothesis assumes that every continuous, entirely hydrophobic sequence of sufficient length, which is not involved in strong intramolecular contacts with other parts of the nascent protein chain, will function as a signal for translocation across the endoplasmic reticulum membrane or across the inner bacterial membrane. The signal peptide is proposed to be deeply immersed into a hydrophobic cleft of the receptor. Accordingly, only the entirely nonpolar peptides can be absorbed and, despite different primary structures, all of them would assume the same conformation dictated by the structure of the receptor pocket.
