Question

If you could take an alpha helix and untwist it and then retwist it up the opposite direction without changing the primary structure of the protein, would it be just as stable?

Answer 1

Specifically I suspect that since all amino acids are of the same chirality, then maybe that implies that the handedness of the alpha helix twist will also always be of the same handedness when folding.

Answer 2

That is indeed correct. Almost all natural occurring amino acids are in l-form. To make a helix that goes the other way around you need the amino acids to be in r-form.

Answer 3

You can also try look at the ramachandran plot for r and l amino acids

Answer 4

Awesome thanks for pointing me in the right direction.