Hinton J F, Easton P L, Newkirk D K, Shungu D C
Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville 72701.
Biochim Biophys Acta. 1993 Mar 14;1146(2):191-6. doi: 10.1016/0005-2736(93)90355-4.
The transport of Na+ ions across phosphatidylcholine/phosphatidylglycerol large unilamellar vesicle membranes facilitated by phenylalanine analogs of gramicidin A has been studied using 23Na-NMR spectroscopy. The four analogs studied were Phe9-, Phe11-, Phe13-and Phe15-gramicidin A. These analogs were found to transport Na+ ions in the following order Phe15 > Phe13 > Phe11 > Phe9. The entropy and enthalpy of activation for the transport of Na+ ions were determined for each analog. A correlation is made between the activation enthalpies and the single channel conductance values of the analogs.
