[Study of interaction between cation fluxes in gramicidin A-modified bilayer phospholipid membranes. Determination of the number of ion-binding sites and their position in the gramicidin channel].
Simultaneous studies were carried out of isotope and electric parameters of spheric bilayer membranes modified with gramicidin A and its analog O-pyromellithylgramicidin (PG) having three negative charges on the N-end of the molecule. The relationship between the electric coefficients of permeability and the isotope ones PG/P* = n was determined by two independent methods. It has been found that for the membranes modified with gramicidin A in RbCl concentrations from 2.2 x 10(-3) to 10(-1) M the value n is constant and approximates 2 and with RbCl concentration 1 M, n = 1.6. For the membranes modified with PG in 0.1 M solutions of PbCl n = 2. The results obtained in terms of the model of unilinear ion diffusion in a narrow pore indicate that in a gramicidin channel there are two sites of cation binding which are located near the channel mouth.
D001665:Binding Sites; D002412:Cations; D002463:Cell Membrane Permeability; D006096:Gramicidin; D007473:Ion Channels; D008051:Lipid Bilayers; D008956:Models, Chemical; D010743:Phospholipids; D012413:Rubidium
D002412:Cations; D007473:Ion Channels; D008051:Lipid Bilayers; D010743:Phospholipids; D006096:Gramicidin; D012413:Rubidium
Issledovanie vzaimodeĭstviia potokov kationov v bisloĭnykh fosfolipidnykh membranakh, modifitsirovannykh gramitsidinom A. Opredelenie chisla ion-sviazyvaiushchikh mest i ikh polozheniia v gramitsidinovom kanale.