Interaction of the E. coli alkaline phosphatase precursor with model phospholipid membranes

Abstract

An interaction of a precursor of the E. coli secreted alkaline phosphatase (prePhoA) containing a signal peptide and model bilayer membranes prepared from the lipids of E. coli has been studied. The interaction was evaluated by monitoring of the state of the lipid phase by fluorescence spectroscopy. The role of the signal peptide in this process was evaluated by a comparative study of the interaction of the mature alkaline phosphatase which does not contain the signal peptide with the model membranes. The precursor was shown to be inserted into the lipid bilayer since the fluorescence anisotropy of a hydrophobic probe, diphenylhexatriene, was enhanced. The intensity of the process is determined by the presence of the signal peptide and depends on the pH of the medium. The data indicate that the mature polypeptide chain of the enzyme also has affinity for the membrane.