23Na-NMR study of ion transport across vesicle membranes facilitated by phenylalanine analogs of gramicidin.
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.
Hinton
J F
JF
Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville 72701.
Easton
P L
PL
Newkirk
D K
DK
Shungu
D C
DC
D006096:Gramicidin / Q000737:chemistry*; D017136:Ion Transport; D009682:Magnetic Resonance Spectroscopy; D008566:Membranes / Q000378:metabolism; D010649:Phenylalanine / Q000031:analogs & derivatives*; D012964:Sodium / Q000378:metabolism*; D013696:Temperature; D014364:Tryptophan
D006096:Gramicidin; D010649:Phenylalanine; D014364:Tryptophan; D012964:Sodium