A high conductance cationic channel from Phaseolus vulgaris roots incorporated into planar lipid bilayers |
| |
Authors: | Balleza Daniel Gómez-Lagunas Froylán Sánchez Federico Quinto Carmen |
| |
Affiliation: | Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, UNAM, Ap. Postal 510-3, Cuernavaca, Morelos 62210, Mexico. |
| |
Abstract: | A previously undescribed plasma membrane cation channel from Phaseolus vulgaris bean roots was studied after its incorporation into planar lipid bilayers. The channel allows the passage of monovalent cations excluding the flux of both anions (Cl-) and divalent cations (Ca2+). The channel presents a high ( approximately 213 pS) conductance in (300 mM Kcis+)/ (150 mMKtrans+) conditions. The probability of opening (Po) is low at all the tested voltages, but it increases significantly at trans-negative potentials. Permeability ratios (Pcation/PK+) under bi-ionic conditions follow the sequence: K+ (1.0)>NH4+ (0.86)>Na+ (0.78). Under the same conditions, the conductance ratios (gamma cation/gamma K+) follow the sequence: NH4+ (1.1) > or = K+ (1.0)>Na+ (0.80). The low probability of opening exhibited by the channel upon its incorporation into a lipid bilayer makes it a candidate to regulation by (and therefore participation in) cellular signalling networks. |
| |
Keywords: | Bean roots Planar lipid bilayers Phaseolus vulgaris |
本文献已被 ScienceDirect PubMed 等数据库收录! |