BCHM 210 Study Guide - Midterm Guide: Acetylcholine, Choline, University Of Manchester
Document Summary
Consists of 6 helices; they are all in different colours. A view looking down through the pore. (b) a side view. Notice that the positively charged s4 region (red) lies on the outside of the structure at the bottom of the pore. The voltage-sensing paddles (s4) lie in the down position below the closed channel (left) this is because the inside of the membrane is negatively charged, so the positive. Membrane depolarization pulls these paddles through the membrane this happens because the inside of the cell is becoming more positive and this repels the s4 leading to the opening of the pore. The motion pulls the base of the channel apart, opening the channel (right). The acetylcholine receptor is a ligand gated channel. The binding of acetylcholine to the receptor changes the permeability to ions within a msec. There is an inward current of na+ and a much smaller outward current of k+ that triggers the action potential.
