SINGLE-CHANNEL BEHAVIOR OF RECOMBINANT BETA(2) GAP JUNCTION CONNEXONSRECONSTITUTED INTO PLANAR LIPID BILAYERS

The beta(2) gap junction protein (Cx26) was expressed in an insect cel l line by infection with a baculovirus vector containing the rat beta( 2) cDNA. Isolated beta(2) gap junction connexons were reconstituted in to planar lipid bilayers. Single channel activity was observed with a unitary conductance of 35-45 pS in 200 mM KCl. Channels with conductan ce values of 60 pS and 90-110 pS also coexisted with the lower conduct ing channel suggesting that there are channels with different conducta nce properties within a population of connexons. Channel activity was observed at voltages of up to 150 mV. Furthermore, the characterizatio n of these channel properties from the beta(2) connexons that were gen erated by this heterologous expression system has provided the basis f or identifying an endogenous beta(2) connexon channel in material reco nstituted from native rat liver gap junctions.