Current noise reveals protonation kinetics and number of ionizable sites in an open protein ion channel

Sergey M. Bezrukov and John J. Kasianowicz
Phys. Rev. Lett. 70, 2352 – Published 12 April 1993
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Abstract

In analogy to current fluctuations found in solid state electronic microstructure devices, excess noise generated by the reversible ionization of sites in a transmembrane ionic channel was observed. By analyzing the pH-dependent fluctuations in the current through fully open single channels formed by the α-toxin protein, we were able to evaluate the protonation rate constants, the number of sites participating in the protonation process, and the effect of recharging a single site on the channel conductance.

  • Received 18 September 1992

DOI:https://doi.org/10.1103/PhysRevLett.70.2352

©1993 American Physical Society

Authors & Affiliations

Sergey M. Bezrukov and John J. Kasianowicz

  • University of Maryland, College Park, Maryland 20742
  • NIDDK/LBM, Biophysics Unit, Building 10, Room 9B07, National Institutes of Health, Bethesda, Maryland 20892
  • Department of Physics, Biotechnology Division, Biosensors Group, Building 222, Room A353, National Institute of Standards Technology, Gaithersburg, Maryland 20899

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Issue

Vol. 70, Iss. 15 — 12 April 1993

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