H. Zhang et Yl. Shi, CATION SELECTIVITY OF CHANNELS FORMED AT PLANAR LIPID BILAYER BY PINELLIA-TERNATA LECTIN, Science in China. Series B, Chemistry, life sciences & earth sciences, 37(5), 1994, pp. 547-556
By means of the two-compartment system, PTL-channels, the first lectin
channels formed on planar lipid bilayers by Pinellia ternata lectin (
PTL) have been studied. The results show (i) PTL-channels are voltage-
independent and have apparent subunits; (ii) in 50 mmol/L KCl and 25 m
mol/L BaCl2 solutions a single channel has unit conductance of 21 pS a
nd 42 pS, respectively; (iii) the channel exhibits a slightly higher p
ermeability to divalent than monovalent cation (P(Ba)/P(K) = 4. 1), an
d (iv) the selectivity among divalent or monovalent cations is poor. T
he cation selectivity sequence for the channel Will follow P(Ba) (7.0)
is similar to P(Sr) (6.4) is similar to P(Mg)(6.4)>P(K)(1.7)>P(Na)(1.
0)is similar to P(Li)(1.0). Moreover, these data also give explanation
to the facilitatory action of PTL on the release of acetyl-choline fr
om motor nerve terminals.