Estimation of the pore size of the large-conductance mechanosensitive ion channel of Escherichia coli

Cruickshank, CC, Minchin, RF, LeDain, AC and Martinac, B (1997) Estimation of the pore size of the large-conductance mechanosensitive ion channel of Escherichia coli. Biophysical Journal, 73 4: 1925-1931.

Author Cruickshank, CC
Minchin, RF
LeDain, AC
Martinac, B
Title Estimation of the pore size of the large-conductance mechanosensitive ion channel of Escherichia coli
Journal name Biophysical Journal   Check publisher's open access policy
ISSN 0006-3495
Publication date 1997-01-01
Sub-type Article (original research)
Volume 73
Issue 4
Start page 1925
End page 1931
Total pages 7
Language eng
Abstract The open channel diameter of Escherichia coli recombinant large-conductance mechanosensitive ion channels (MscL) was estimated using the model of Hille (Hille, B. 1968. Pharmacological modifications of the sodium channels of frog nerve. J. Gen. Physiol. 51:199-219)that relates the pore size to conductance. Based on the MscL conductance of 3.8 nS, and assumed pore lengths, a channel diameter of 34 to 46 Angstrom was calculated. To estimate the pore size experimentally, the effect of large organic ions on the conductance of MscL was examined. Poly-L-lysines (PLLs) with a diameter of 37 Angstrom or larger significantly reduced channel conductance, whereas spermine (similar to 15 Angstrom), PLL19 (similar to 25 Angstrom) and 1,1'-bis-(3-(1'-methyl-(4,4'-bipyridinium)-1-yl)-propyl)-4,4'-bipyridinium (similar to 30 Angstrom) had no effect. The smaller organic ions putrescine, cadaverine, spermine, and succinate all permeated the channel. We conclude that the open pore diameter of the MscL is similar to 40 Angstrom, indicating that the MscL has one of the largest channel pores yet described. This channel diameter is consistent with the proposed homohexameric model of the MscL.
Keyword Biophysics
Patch-clamp
Functional Reconstitution
Membrane
Cells
Permeation
Junction
Neurons
Mscl
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Biomedical Sciences Publications
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 169 times in Thomson Reuters Web of Science Article | Citations
Google Scholar Search Google Scholar
Created: Tue, 14 Aug 2007, 02:59:34 EST