Re: Q: Helix dipoles

Cristina Cantale (
Fri, 15 Mar 1996 14:01:08 +0100

On 4/3/96 you wrote:
> Here's the question I'd like to pose...
> Imagine that you have two "ideal" (i.e. no distortions from regular
> geometry) helices in similar environments in a protein: one an
> alpha-helix; the other a 3-10- helix. And imagine further that
> these two helices are of the same length.
> Which (if either) of the two helices would you predict has the greater
> dipole moment, and why?
So, I think that alpha-helix in this example has a greater dipole moment
than the 3-10 helix.
In the proposed approximation, the total dipole moment in an helix is the
sum of the contributes coming from the dipoles present in each AA.
The dipoles coming from the C-O and N-H in each AA are parallel to the axis
of helix if this is an alpha elix.In 3-10 helix, C-O and N-H bonds of each
AA form an angle with the axis, so just a componet of each dipole contribute
to the final value.