Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Search research articles

Related Experiment Videos

Ca2+-gramicidin A interactions and blocking effects on the ionic channel.

F Heitz, C Gavach

Biophysical Chemistry

|September 1, 1983

Summary

Calcium ions (Ca2+) bind to gramicidin A, blocking alkali metal ion transport. This competitive binding, dependent on voltage, explains ion channel blockage and conductance changes.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Durvalumab with carboplatin/paclitaxel and bevacizumab followed by durvalumab and bevacizumab with or without olaparib maintenance in newly diagnosed non-BRCA-mutated advanced ovarian cancer.

Annals of oncology : official journal of the European Society for Medical Oncology·2025

Same author

Niraparib first-line maintenance therapy in patients with newly diagnosed advanced ovarian cancer: final overall survival results from the PRIMA/ENGOT-OV26/GOG-3012 trial.

Annals of oncology : official journal of the European Society for Medical Oncology·2024

Same author

Maintenance olaparib rechallenge in patients with platinum-sensitive relapsed ovarian cancer previously treated with a PARP inhibitor (OReO/ENGOT-ov38): a phase IIIb trial.

Annals of oncology : official journal of the European Society for Medical Oncology·2023

Same author

Association of location of BRCA1 and BRCA2 mutations with benefit from olaparib and bevacizumab maintenance in high-grade ovarian cancer: phase III PAOLA-1/ENGOT-ov25 trial subgroup exploratory analysis.

Annals of oncology : official journal of the European Society for Medical Oncology·2022

Same author

Depression and anxiety in women with malignant ovarian germ cell (MOGCT) and sex cord stromal tumors (SCST): an analysis of the AGO-CORSETT database.

Archives of gynecology and obstetrics·2022

Same author

Early tumor regrowth is a contributor to impaired survival in patients with completely resected advanced ovarian cancer. An exploratory analysis of the Intergroup trial AGO-OVAR 12.

Gynecologic oncology·2018

Area of Science:

Biophysics
Ion Channel Function
Spectroscopic Analysis

Background:

Gramicidin A forms ion channels across lipid bilayers.
Alkali metal ions like Cs+ and K+ are transported through these channels.
Calcium ions (Ca2+) are known to affect ion transport, but the mechanism is unclear.

Purpose of the Study:

To elucidate the interaction between Ca2+ and gramicidin A.
To explain the blocking mechanism of Ca2+ on alkali metal ion transport.
To develop a model accounting for Ca2+ effects on channel conductance.

Main Methods:

Spectroscopic techniques including infrared (IR), circular dichroism (CD), and 13C-NMR.
Analysis of Ca2+ binding sites on gramicidin A dimers.
Electrophysiological measurements of single-channel conductance and current-voltage relationships.

Main Results:

Spectroscopic data confirm Ca2+ interaction with gramicidin A.
Two Ca2+-binding sites were identified near the COOH termini of head-to-head gramicidin A dimers.
Ca2+ binding is competitive with Cs+ and K+ binding and is voltage-dependent.
A model was proposed explaining Ca2+ blockage and its influence on conductance.

Conclusions:

Ca2+ binds to specific sites on gramicidin A, competitively inhibiting alkali metal ion transport.
The voltage-dependent binding of Ca2+ explains its blocking effect and modulation of channel conductance.
This study provides a mechanistic understanding of Ca2+ modulation of gramicidin A ion channels.

Related Experiment Videos