The effect of sulfur stereochemistry of l-β,β-dimethylmethionine S-oxide on the physicochemical properties of truncated polytheonamides

l-β,β-Dimethylmethionine S-oxide is a unique amino acid found in polytheonamides. Four designed hexapeptides containing the sulfide, (SR)-sulfoxide, (SS)-sulfoxide, and sulfone derivatives of l-dimethylmethionine were synthesized and functionally analyzed. Our results indicate that the sulfoxide stereochemistry of the peptides controls their overall physicochemical properties.