Examining noise sources at the single-molecule level: 1/f noise of an open maltoporin channel.
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.
Bezrukov
S M
SM
Laboratory of Physical and Structural Biology, NICHD, NIH, Bethesda, Maryland 20892-0924, USA.
Winterhalter
M
M
D016477:Artifacts; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000737:chemistry; D001692:Biological Transport; D004553:Electric Conductivity; D004594:Electrophysiology / Q000379:methods*; D015640:Ion Channel Gating; D008958:Models, Molecular; D009844:Oligosaccharides / Q000737:chemistry; D018272:Porins; D011991:Receptors, Virus / Q000737:chemistry*
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D009844:Oligosaccharides; D018272:Porins; D011991:Receptors, Virus; C016532:maltoporins; C016549:maltohexaose