Protein secondary structures and d-serine?

Question

If a polypeptide consisting of 6-residues of D-serine were dissolved in aqueous solution at pH 7.4, what secondary structure do you think that it would adopt?

Answer 1

L-serine is the usual version found in our proteins.  As far as I understand, D-serine would have the exact same biophysical properties, but with opposite stereospecificity.

So:  Wikipedia says that L-serine is a poor substrate for forming an alpha helix.  My two guesses for what would form are:  an alpha helix, with the opposite orientation from the ones found in our proteins, or an unstructured and mobile blob - a so-called molten globule.  I guess since serine isn't so good for helices, I favor the later.

In support of this, I submitted a random sequence that included a string of 6 serines at the second link, and it identified no structure associated with the SSSSSStretch.

But this is pretty much guesswork;  check your book for descriptions of polyserine structures and think about what the D- version would do.

Hope this helps.