Examining Noise Sources at the Single-Molecule Level: <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1</mn><mi>/</mi><mi mathvariant="italic">f</mi></math></span> Noise of an Open Maltoporin Channel

Sergey M. Bezrukov; Mathias Winterhalter

doi:10.1103/PhysRevLett.85.202

Examining Noise Sources at the Single-Molecule Level: $1 / f$ Noise of an Open Maltoporin Channel

Sergey M. Bezrukov and Mathias Winterhalter

Phys. Rev. Lett. 85, 202 – Published 3 July 2000

Abstract

We have studied the phenomenological origin of $1 / f$ noise in a solute-specific bacterial ion channel, maltoporin. We show that after excision of small, but resolvable stepwise changes in the recordings of the current through a single open channel, the $1 / f$ noise component disappears and the channel exhibits noise that is “white” below 100 Hz. Combined with results of a recent noise study of several bacterial porins, our observations suggest that $1 / f$ noise is caused by the equilibrium conductance fluctuations related to the conformational flexibility of the channel pore structural constituents.

Received 5 January 2000

DOI:https://doi.org/10.1103/PhysRevLett.85.202

Authors & Affiliations

Sergey M. Bezrukov^1,2 and Mathias Winterhalter^3,4

¹Laboratory of Physical and Structural Biology, NICHD, NIH, Bethesda, Maryland 20892-0924
²St. Petersburg Nuclear Physics Institute, Gatchina, Russia 188350
³Department of Biophysical Chemistry, Biozentrum, Basel, Switzerland
⁴IPBS-CNRS, Toulouse, France