Detection of the C-terminal Propeptide of Proaerolysin by Aerolysin Nanopore

Abstract

Electrophysiological studies of the interaction of polymers with bacterial pores provide a stratagem for single molecule detection. Aerolysin (AeL) nanopore is a promising emerging bacterial nanopore that has been extensively used for single nucleotide discrimination of very short oligonucleotides (<10 nt) with labeling. Due to its narrow constriction which is approximate 1.4 nm and highly charged pore lumen, AeL nanopore exhibits a high sensitivity in short peptide and DNA detection. Before forming the bacterial nanopore, aerolysin monomer was usually conversed from proaerolysin by activated with trypsin. The C-terminal peptide (CTP) part of proaerolysin was cleavage and the remaining part is defined as the aerolysin monomer. The CTP peptide is not uniformly charged with electrostatic distribution as positive-negative-neutral in neutral buffer solution. Here we investigated the structure of CTP during translocation through aerolysin nanopore under applied potential. The result based on characteristic blockages showed that the capture and translocation of the peptides are governed by the charged residues in the pore lumen and the potential applied.