Oriented Single Directional Insertion of Nanochannel of Bacteriophage SPP1 DNA Packaging Motor into Lipid Bilayer via Polar Hydrophobicity

Abstract

Insertion of biological nanopore into artificial membrane is of fundamental importance in nanotechnology. Many applications require control and knowledge of channel orientation. In this work, the insertion orientation of the bacteriophage SPP1 and phi29 DNA packaging motor into lipid membranes was investigated. Single molecule electrophysiological assays and Ni-NTA-nanogold binding assays revealed that both SPP1 and phi29 motor channels exhibited a one-way traffic property for TAT peptide translocation from N- to C-termini of the protein channels. SPP1 motor channels preferentially inserts into liposomes with their C-terminal wider region facing inward. Changing the hydrophobicity of the N- or C-termini of phi29 connector alters the insertion orientation, suggesting that the hydrophobicity and hydrophilicity of the termini of the protein channel governs the orientation of the insertion into lipid membrane. It is proposed that the specificity in motor channel orientation is a result of the hydrophilic/hydrophobic interaction at the air/water interface when the protein channels are incorporating into liposome membranes.