Week 6 Bollough Lecture 12

Question 1

What do the different variations of the K+ channel have in common?

Answer 1

All have the same basic core

a) The core has 2 TM helices, a short ‘pore’ helix and a signature sequence in the selectivity filter
b) Some have additional cytosolic domains are typically involved in regulation

Question 2

What do K+ channels usually select for?

Answer 2

Selective for; K+> Rb+>NH4+>Na+>Li+

Question 3

what is the structure of the selectivity of molecules in K+ channels?

Answer 3

The channel is a tetramer, there are loops that meet in the middle and have many C=O bonds which allow for the selectivity filter to work

Question 4

What is the general structure of K+ channels?

Answer 4

There are 4 subunits;

a) Each made out of 3 types of helices
i) Outer helix which interacts with the membrane
ii) Inner helix is used to close or open the pore
iii) Pore helix (half a helix) contains the selectivity filter