Optically Active Polyampholytes Derived from L- and D-Carbylanayl-L-histidine

Synthesis and characterization of polyisocyanides derived from alanine and glycine dipeptides

“…The optical rotation of the compounds expressed per repeat unit increased by an order of magnitude from the monomers to the polymers (Table II). Similar results previously have been observed and have been attributed to the formation of helical secondary structures in the polymers 5, 6…”

“…In this article, we describe the synthesis of optically active polyisocyanides derived from dipeptides of alanine in which a stable helical conformation is obtained because of the presence of hydrogen bonding interactions between the side chains of the polymers [Fig. 1(c)] 5–7. To investigate the interplay between hydrogen bonding and stereochemistry in these polyisocyanopeptides, we analyzed their physical data and compared them with data for alanine–glycine‐ and glycine–alanine‐based polymers.…”

Conformational analysis of dipeptide‐derived polyisocyanides

“…For the polyisocyanopeptides previously discussed, the presence of a hydrogen‐bonding array between the amide groups is in all cases (i.e., L,L ‐PIAA, L , D ‐PIAA, and L ‐PIGA) accompanied by a strong positive Cotton effect around λ = 315 nm attributed to a right‐handed ( P ) helix, whereas for the polyisocyanides in which these arrays were absent (i.e., L ‐PIAG and L , D ‐PIAA after TFA treatment), CD spectra were obtained lacking this signal. For polyisocyanopeptides derived from alanyl–serine35 and alanyl–histidine36, 37 prepared in the past by our group, similar differences in CD spectra were observed, including differences between the two stereoisomers of poly(isocyanoalanyl serine methyl ester), L,L ‐PIAS36, 37 and L , D ‐PIAS, and between the two stereoisomers of poly(isocyanoalanyl histidine methyl ester), L,L ‐PIAH and D , L ‐PIAH (Fig. 8).…”

“… CD spectra of (A) L,L ‐PIAS,36, 37 (B) L , D ‐PIAS,36, 37 (C) L,L ‐PIAH,35 (D) D , L ‐PIAH,35 and (E) poly( L ‐isocyanoalanyl‐ L ‐ O ‐acetyl histidinol) [ D , L ‐PIAH(OAc)] 36, 37…”

Intra- and Interpolyelectrolyte Complexes of Polyampholytes

“…Carlo method [79] and molecular dynamics simulations [80,81] have been conducted to explain the polyampholyte-polyelectrolyte complexation as a function of charge distribution of a polyampholyte, nature of solvent and salt. The structure of polyelectrolyte-polyampholyte complexes strongly depends on the charge distribution of polyampholyte chain.…”