Nanopore analysis of tethered peptides.
Peptides of 12 amino acids were tethered via a terminal cysteine to mono-, di-, tri-, and tetrabromomethyl-substituted benzene to produce bundles of one to four peptide strands (CY12-T1 to CY12-T4, respectively). The interaction of the bundles with the α-hemolysin pore was assessed by measuring the blockade currents (I) and times (T) at an applied potential of - 50, - 100, and - 150 mV. Three types of events could be distinguished: bumping events, with small I and short T where the molecule transiently interacts with the pore before diffusing away; translocation events, where the molecule threads through the pore with large I and the value of T decreases with increasing voltage; and intercalation events, where the molecule transiently enters the pore but does not translocate with large I and the value of T increases with increasing voltage. CY12-T1 and CY12-T2 gave only bumping and translocation events; CY12-T3 and CY12-T4 also gave intercalation events, some of which were of very long duration. The results suggest that three uncoiled peptide strands cannot simultaneously thread through the α-hemolysin pore and that proteins must completely unfold in order to translocate.
Meng
Howard
H
Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK, Canada.
Detillieux
Dielle
D
Baran
Christian
C
Krasniqi
Besnik
B
Christensen
Christopher
C
Madampage
Claudia
C
Stefureac
Radu I
RI
Lee
Jeremy S
JS
D006460:Hemolysin Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology; D010455:Peptides / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*
D006460:Hemolysin Proteins; D010455:Peptides