The gramicidin A channel: theoretical energy profile computed for single occupancy by a divalent cation, Ca2+

Catherine Etchebest, Alberte Pullman, Shoba Ranganathan

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The energy profile for the interaction of the divalent cation Ca2+ with the gramicidin A channel has been computed, introducing successively the different structural components of the channel, namely the polypeptide backbone, the ethanolamine tails and the amino acid side chains. The calculations have been performed in two fashions: (1) with the tail fixed in its most stable conformation, (2) with the tail allowed to optimize its conformation upon progression of the cation. The introduction of the tail and more particularly of its flexibility modifies considerably the profile. On the other hand, in both cases, the introduction of the side chains does not modify qualitatively the overall shape of the energy profile, although it brings about a general lowering of the energies. When the tail is mobile, a very deep and narrow minimum is found at 10.5 Å from the center and the central barrier is roughly 21 kcal/mol. The similarities and differences found with respect to the corresponding profiles for alkali ions, Na+ in particular, are discussed in connection with the very low permeability, if any, of gramicidin A for Ca2+.

LanguageEnglish
Pages23-30
Number of pages8
JournalBBA - Biomembranes
Volume818
Issue number1
DOIs
Publication statusPublished - 8 Aug 1985
Externally publishedYes

Fingerprint

Gramicidin
Divalent Cations
Conformations
Ethanolamine
Alkalies
Cations
Permeability
Ions
Amino Acids
Peptides

Keywords

  • Ca
  • Energy profile
  • Gramicidin A
  • Ion channel

Cite this

@article{b0c45a7e947c4387a6de3a6b257dd4a9,
title = "The gramicidin A channel: theoretical energy profile computed for single occupancy by a divalent cation, Ca2+",
abstract = "The energy profile for the interaction of the divalent cation Ca2+ with the gramicidin A channel has been computed, introducing successively the different structural components of the channel, namely the polypeptide backbone, the ethanolamine tails and the amino acid side chains. The calculations have been performed in two fashions: (1) with the tail fixed in its most stable conformation, (2) with the tail allowed to optimize its conformation upon progression of the cation. The introduction of the tail and more particularly of its flexibility modifies considerably the profile. On the other hand, in both cases, the introduction of the side chains does not modify qualitatively the overall shape of the energy profile, although it brings about a general lowering of the energies. When the tail is mobile, a very deep and narrow minimum is found at 10.5 {\AA} from the center and the central barrier is roughly 21 kcal/mol. The similarities and differences found with respect to the corresponding profiles for alkali ions, Na+ in particular, are discussed in connection with the very low permeability, if any, of gramicidin A for Ca2+.",
keywords = "Ca, Energy profile, Gramicidin A, Ion channel",
author = "Catherine Etchebest and Alberte Pullman and Shoba Ranganathan",
year = "1985",
month = "8",
day = "8",
doi = "10.1016/0005-2736(85)90133-6",
language = "English",
volume = "818",
pages = "23--30",
journal = "BBA - Biomembranes",
issn = "0005-2736",
publisher = "Elsevier",
number = "1",

}

The gramicidin A channel : theoretical energy profile computed for single occupancy by a divalent cation, Ca2+. / Etchebest, Catherine; Pullman, Alberte; Ranganathan, Shoba.

In: BBA - Biomembranes, Vol. 818, No. 1, 08.08.1985, p. 23-30.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - The gramicidin A channel

T2 - BBA - Biomembranes

AU - Etchebest, Catherine

AU - Pullman, Alberte

AU - Ranganathan, Shoba

PY - 1985/8/8

Y1 - 1985/8/8

N2 - The energy profile for the interaction of the divalent cation Ca2+ with the gramicidin A channel has been computed, introducing successively the different structural components of the channel, namely the polypeptide backbone, the ethanolamine tails and the amino acid side chains. The calculations have been performed in two fashions: (1) with the tail fixed in its most stable conformation, (2) with the tail allowed to optimize its conformation upon progression of the cation. The introduction of the tail and more particularly of its flexibility modifies considerably the profile. On the other hand, in both cases, the introduction of the side chains does not modify qualitatively the overall shape of the energy profile, although it brings about a general lowering of the energies. When the tail is mobile, a very deep and narrow minimum is found at 10.5 Å from the center and the central barrier is roughly 21 kcal/mol. The similarities and differences found with respect to the corresponding profiles for alkali ions, Na+ in particular, are discussed in connection with the very low permeability, if any, of gramicidin A for Ca2+.

AB - The energy profile for the interaction of the divalent cation Ca2+ with the gramicidin A channel has been computed, introducing successively the different structural components of the channel, namely the polypeptide backbone, the ethanolamine tails and the amino acid side chains. The calculations have been performed in two fashions: (1) with the tail fixed in its most stable conformation, (2) with the tail allowed to optimize its conformation upon progression of the cation. The introduction of the tail and more particularly of its flexibility modifies considerably the profile. On the other hand, in both cases, the introduction of the side chains does not modify qualitatively the overall shape of the energy profile, although it brings about a general lowering of the energies. When the tail is mobile, a very deep and narrow minimum is found at 10.5 Å from the center and the central barrier is roughly 21 kcal/mol. The similarities and differences found with respect to the corresponding profiles for alkali ions, Na+ in particular, are discussed in connection with the very low permeability, if any, of gramicidin A for Ca2+.

KW - Ca

KW - Energy profile

KW - Gramicidin A

KW - Ion channel

UR - http://www.scopus.com/inward/record.url?scp=0022348773&partnerID=8YFLogxK

U2 - 10.1016/0005-2736(85)90133-6

DO - 10.1016/0005-2736(85)90133-6

M3 - Article

VL - 818

SP - 23

EP - 30

JO - BBA - Biomembranes

JF - BBA - Biomembranes

SN - 0005-2736

IS - 1

ER -