Equilibrium binding constants for the group I metal cations with gramicidin-A determined by competition studies and T1+-205 nuclear magnetic resonance spectroscopy.
| Publication Type | Academic Article |
| Authors | Hinton J, Whaley W, Shungu D, Koeppe R, Millett F |
| Journal | Biophys J |
| Volume | 50 |
| Issue | 3 |
| Pagination | 539-44 |
| Date Published | 09/01/1986 |
| ISSN | 0006-3495 |
| Keywords | Gramicidin |
| Abstract | The equilibrium binding constants of the Group I metal cations with gramicidin A in aqueous dispersions of lyso-PC have been determined using a combination of competitive binding with the T1+ ion and T1-205 NMR spectroscopy. The values of the binding constants at 34 degrees C are Li (32.2 M-1), Na (36.9 M-1), K (52.6 M-1), Rb (55.9 M-1), and Cs (54.0 M-1). The equilibrium binding constant for the T1+ ion at this temperature is 582 M-1. The relationships between the binding constants, the free energy of the binding process, and the cation selectivity of the gramicidin A channel are discussed. |
| DOI | 10.1016/S0006-3495(86)83492-0 |
| PubMed ID | 2428415 |
| PubMed Central ID | PMC1329731 |