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Nonbonded interactions in membrane active cyclic biopolymers. IV - Cation dependenceInteractions of valinomycin and form of its analogs in several conformations with the central ions Li(+), Na(+), K(+), Rb(+) and Cs(+) are investigated as part of a study of the specific preference of valinomycin for potassium and the mechanisms of carrier-mediated ion transport across membranes. Ion binding energies and conformational potential energies are calculated taking into account polarization energy formulas and repulsive energy between the central ion and the ligand atoms for conformations representing various stages in ion capture and release for each of the two ring chiralities of valinomycin and its analogs. Results allow the prediction of the chirality and conformation most likely to be observed for a given analog, and may be used to synthesize analogs with a desired rigidity or flexibility. The binding energies with the alkali metal cations are found to decrease with increasing ion size, and to be smaller than the corresponding ion hydration energies. It is pointed out that the observed potassium preference may be explainable in terms of differences between binding and hydration energies. Binding energies are also noted to depend on ligand conformation.
Document ID
19810057726
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Radhakrishnan, R.
(Madras Univ. India)
Srinivasan, S.
(Madras Univ. India)
Prasad, C. V.
(Madras Univ. India)
Brinda, S. R.
(Madras, University Madras, India)
Macelroy, R. D.
(NASA Ames Research Center Moffett Field, CA, United States)
Sundaram, K.
(Madras Univ. India)
Date Acquired
August 11, 2013
Publication Date
January 1, 1980
Subject Category
Inorganic And Physical Chemistry
Accession Number
81A42130
Distribution Limits
Public
Copyright
Other

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