English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Estimation of Na+ dwell time in the gramicidin A channel. Na+ ions as blockers of H+ currents.

Heinemann, S., & Sigworth, F. J. (1989). Estimation of Na+ dwell time in the gramicidin A channel. Na+ ions as blockers of H+ currents. Biochimica et Biophysica Acta (BBA) - Biomembranes, 987(1), 8-14. doi:10.1016/0005-2736(89)90448-3.

Item is

Basic

show hide
Item Permalink: http://hdl.handle.net/11858/00-001M-0000-002B-B7C4-C Version Permalink: http://hdl.handle.net/11858/00-001M-0000-002B-B7C5-A
Genre: Journal Article

Files

show Files
hide Files
:
2358782.pdf (Publisher version), 513KB
Name:
2358782.pdf
Description:
-
Visibility:
Public
MIME-Type / Checksum:
application/pdf / [MD5]
Technical Metadata:
Copyright Date:
-
Copyright Info:
-
License:
-

Locators

show

Creators

show
hide
 Creators:
Heinemann, S.H.1, Author              
Sigworth, F. J., Author
Affiliations:
1Department of Membrane Biophysics, MPI for biophysical chemistry, Max Planck Society, ou_578579              

Content

show
hide
Free keywords: -
 Abstract: The permeation of Na+ through gramicidin A channels shows a simple saturation with increasing Na+ concentration that can be described by two different models. The first model assumes that one Na+ binds to the channel with high affinity (≈ 30 M−1) and that conduction occurs by a ‘knock-on’ mechanism requiring double occupancy of the channel; the other model assumes that Na+ binding is of low affinity (< 1 M−1), and that double occupancy of the channel is rare. NMR measurements have shown tight Na+ binding, favoring the first model, but measurements of flux ratios and water transport support the second model. We present here a relatively model-independent measurement of the dwell time of Na+ inside the channel, in which we characterize the fluctuations in H+ current through the channel induced by ‘block’ from the more slowly permeating Na+ ions. The mean Na+ dwell time inside the channel is estimated to be ≈ 10 ns at a membrane potential of 200 mV. This result is inconsistent with tight Na+ binding, thus favoring the second model.

Details

show
hide
Language(s): eng - English
 Dates: 1989-12
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Method: Peer
 Identifiers: DOI: 10.1016/0005-2736(89)90448-3
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Biochimica et Biophysica Acta (BBA) - Biomembranes
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: -
Pages: - Volume / Issue: 987 (1) Sequence Number: - Start / End Page: 8 - 14 Identifier: -