The transport of ions, such as sodium and potassium, across cell membranes is a critically important process for all living systems. This transport is necessary for life; for example, it is directly involved in the transmission of signals along nerves and the production of metabolic energy. Ion transport is facilitated and controlled by protein structures, called ion- channels, that reside in the cell membrane. While these ion- channels can be identified, their structures are not well understood at a molecular level. These ion-channels can be "gated" open by small molecules called neurotransmitters or by changes in electric fields that occur in the cell membrane. At present, the structural changes that open ion-channels are not characterized. The objective of the research project is to advance the understanding of ion-channels. A membrane ion-channel that is opened by the neurotransmitter acetylcholine, called the acetylcholine receptor, will be studied. This channel proves to be an ideal system for chemical/physical study because it can be obtained in large quantities. Using powerful new chemical and physical techniques, the molecular structure of the acetylcholine receptor and the mechanism by which it opens ion channels will be examined. Since electric fields also can open ion-channels, the effects of electric fields on proteins in cell membranes will be studied. Small proteins will be designed and produced so as to investigate interactions between proteins and electric fields in membranes.
