ligand-gated ion channels  Dr Engelbert Buxbaum
engelbert_buxbaum at Tue Nov 4 00:32:04 EST 2003  chrissy wrote:
> Hi!  I hope you'll allow what might be a simple question to
some of > you, but I haven't been able to find answers
elsewhere. > With a multisubunit ion channel, where the subunits
have multiple > transmembrane helices, how do you tell which of
a subunit's helices is > the porelining helix?  And what are the
features that predict > cation/anion selectivity?  Does this
have something to do with the > amino acid sequence or is it
more complex? > I just finished an introductory lecture series
on it, but the lecturer > wasn't very clear.  She used the
acetylcholine receptor as an example, > and said something about
a 9' leucine, but I can't find an explanation > of that term
anyway.  And how does that relate to ligand-gated > channels in
general?  Our knowledge on this topic is still rather limited.
However, physical chemistry tells us that the channel must be
lined with polar and ionised amino acids