Next Article in Journal
Different Routes to Inhibit Fatty Acid Amide Hydrolase: Do All Roads Lead to the Same Place?
Next Article in Special Issue
Cooperative Binding of KaiB to the KaiC Hexamer Ensures Accurate Circadian Clock Oscillation in Cyanobacteria
Previous Article in Journal
Conflicting Roles of 20-HETE in Hypertension and Stroke
Previous Article in Special Issue
TRPM6 N-Terminal CaM- and S100A1-Binding Domains
Open AccessArticle

Cooperativity and Steep Voltage Dependence in a Bacterial Channel

Department of Biology, University of Maryland, College Park, MD 20742, USA
*
Author to whom correspondence should be addressed.
Int. J. Mol. Sci. 2019, 20(18), 4501; https://doi.org/10.3390/ijms20184501
Received: 12 August 2019 / Revised: 2 September 2019 / Accepted: 4 September 2019 / Published: 11 September 2019
(This article belongs to the Collection Feature Papers in Molecular Biophysics)
This paper reports on the discovery of a novel three-membrane channel unit exhibiting very steep voltage dependence and strong cooperative behavior. It was reconstituted into planar phospholipid membranes formed by the monolayer method and studied under voltage-clamp conditions. The behavior of the novel channel-former, isolated from Escherichia coli, is consistent with a linearly organized three-channel unit displaying steep voltage-gating (a minimum of 14 charges in the voltage sensor) that rivals that of channels in mammalian excitable membranes. The channels also display strong cooperativity in that closure of the first channel permits the second to close and closure of the second channel permits closure of the third. All three have virtually the same conductance and selectivity, and yet the first and third close at positive potentials whereas the second closes at negative potentials. Thus, is it likely that the second channel-former is oriented in the membrane in a direction opposite to that of the other two. This novel structure is named “triplin.” The extraordinary behavior of triplin indicates that it must have important and as yet undefined physiological roles.
Keywords: Escherichia coli; planar membrane; pore; dipole; electrophysiology; voltage gating Escherichia coli; planar membrane; pore; dipole; electrophysiology; voltage gating
Show Figures

Graphical abstract

MDPI and ACS Style

Lin, S.H.; Chang, K.-T.; Cherian, N.; Wu, B.; Phee, H.; Cho, C.; Colombini, M. Cooperativity and Steep Voltage Dependence in a Bacterial Channel. Int. J. Mol. Sci. 2019, 20, 4501.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map

1
Back to TopTop