Slowing down single-molecule trafficking through a protein nanopore reveals intermediates for peptide translocation.
The microscopic details of how peptides translocate one at a time through nanopores are crucial determinants for transport through membrane pores and important in developing nano-technologies. To date, the translocation process has been too fast relative to the resolution of the single molecule techniques that sought to detect its milestones. Using pH-tuned single-molecule electrophysiology and molecular dynamics simulations, we demonstrate how peptide passage through the α-hemolysin protein can be sufficiently slowed down to observe intermediate single-peptide sub-states associated to distinct structural milestones along the pore, and how to control residence time, direction and the sequence of spatio-temporal state-to-state dynamics of a single peptide. Molecular dynamics simulations of peptide translocation reveal the time- dependent ordering of intermediate structures of the translocating peptide inside the pore at atomic resolution. Calculations of the expected current ratios of the different pore-blocking microstates and their time sequencing are in accord with the recorded current traces.
1] Department of Physics, Alexandru I. Cuza University, Iasi, Romania [2].
Loredana
L
Mereuta
1] Department of Chemistry, University of California, Irvine CA 92697, USA [2].
Mahua
M
Roy
Department of Interdisciplinary Research, Alexandru I. Cuza University, Iasi, Romania.
Alina
A
Asandei
Research Center for Proteineous Materials, Chosun University, Gwangju, South Korea.
Jong Kook
JK
Lee
Research Center for Proteineous Materials, Chosun University, Gwangju, South Korea.
Yoonkyung
Y
Park
Department of Chemistry, University of California, Irvine CA 92697, USA.
Ioan
I
Andricioaei
Department of Physics, Alexandru I. Cuza University, Iasi, Romania.
Tudor
T
Luchian
D000595:Amino Acid Sequence; D006863:Hydrogen-Ion Concentration; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D058608:Nanopores; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*
D010455:Peptides; D011506:Proteins