Unsaturated amino-acid residues as probes for the conformation of polypeptides in solution (original) (raw)

Acetyl-(dehydro-Phe) and acetyl-bis(dehydr0-Phe) groups have been attached to the c-amino group of the lysine residues of the copolymer poly(Glug2Lyss) by reacting this last with acetyl-(dehydro-Phe)-azlactone and acetyl-bis(dehydr0-Phe)-azlactone, respectively. In the latter case induced CD is observed between 250 and 330 nm, due to the relative dissymmetric disposition of the two dehydro-Phe groups under the chiral field of the polypeptide chain. pH dependence of the induced CD, observed for the copolymer and lacking in the lowmolecular-weight structural model, is related to the a-helical and random coiled conformation of the polypeptide chain.