Cation channel formed at lipid bilayer by Cinnamomin, a new type II ribosome-inactivating protein

Abstract

Cinnamomin, a new type II ribosome-inactivating protein, purified from the seeds of Cinnamonum camphora is reconstituted into the membranes of planar lipid bilayer and giant liposome. The channel-forming activity of the cinnamomin is found and cation permeability of the channel is characterized by patch clamp. In an asymmetric solution system, bath 150/pipette 100 mM KCl, the unit conductance is 140±7 pS and the reversal potential is 10.4±0.6 mV, very close to the theoretical value of the K + electrode. The results offer an interpretation for internalization of the RIP and the cytotoxicity difference between single and two chain RIP.