Prof. Dr. Ernst Bamberg
Dept. Biophysikalische Chemie
Max-Planck-Institut fuer Biophysik
Frankfurt, Germany

Friday, July 18, 2003
10:00 am (CT)
3269 Beckman Institute

Abstract

Channelopsin 1 and 2 from Chlamydomonas reinhardtii were identified to form a 7-trans-membrane helix structure similar to that of rhodopsin and bacteriorhodopsin. Channelrhodopsins carry as chromophore retinal which is linked via a Schiff base to a lysine on the peptide chain of the protein. It is demonstrated that Channelrhodopsin 1 and 2 function as light-gated ion channels which are permeable to H+ and monovalent as well as divalent cations. For the first time light-gated channels are described and with the 7-trans-membrane helix motif a new class of ion channels is identified. The properties of these channels have been investigated by electrophysiological methods and their possible roles as light receptors in Chlamydomonas reinhardtii are discussed along with possible technical applications.