I'm very sorry... we have just had a mistake in the self-assessment
questions pointed out to us.
Question 14 should read...
14. Why are cations often bound to the C-terminal of alpha-helices?
I would also like to remind you all that your answers should be submitted
to your tutor by next Monday (16th). See
http://pps98.cryst.bbk.ac.uk/groups/pps.tutorialgroups98.html
Good luck, and best wishes,
Clare Sansom
c.sansom@mail.cryst.bbk.ac.uk
Coordinating Tutor, Principles of Protein Structure