Circular dichroism and nuclear magnetic resonance studies on the complexation of valinomycin with calcium

Vishwanath, CK and Easwaran, KRK (1982) Circular dichroism and nuclear magnetic resonance studies on the complexation of valinomycin with calcium. In: Biochemistry, 21 (11). pp. 2612-2621.

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Abstract

Complexation of valinomycin (VM) with the divalent cation Ca2+ in a lipophilic solvent, acetonitrile (CH3-CN), has been studied by using circular dichroism and proton and carbon- 13 nuclear magnetic resonance (‘H NMR and I3C NMR). From analyses of the spectral data, it is concluded that VM forms a 2:l (peptideion-peptide) sandwich complex with Ca2+, at low concentration of VM. At moderate conocentrations of the salt, in addition to the sandwich complex, an equimolar (1:l) complex different from those observed for potassium and sodium is also observed. At very large concentrations of the calcium salt, the data suggested a complex with a conformation similar to that of the free VM in polar solvents. Possible conformations for the sandwich and the equimolar VM-calcium complexes are proposed.

Item Type:	Journal Article
Publication:	Biochemistry
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	22 Jul 2009 07:11
Last Modified:	19 Sep 2010 05:38
URI:	http://eprints.iisc.ac.in/id/eprint/21706

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