N-Substituted Poly(α-amino acids). 2. Conformational Properties of Poly(γ-ethyl N-methyl-L-glutamate) in Various Solvent Mixtures

Convenient synthetic approach to poly(N‐Methyl L‐alanine) through polycondensation of activated urethane derivative of N‐methyl L‐alanine

“…The circular dichroism (CD) spectra of PNMA was also conducted in the aqueous and TFE solution, where the negative Cotton peak at 220–225 nm was observed, indicating formation of a right‐handed helix structure from all‐trans peptide configurations (Supporting Information Fig. S4), that agree with N ‐methylated polypeptides produced by solid‐state synthesis or NCA polymerization in the literature …”

“…These polypeptoids have been anticipated to be used as a drug delivery carrier, and construction of antifouling surface . N ‐Substituted polypeptide with substitution group at α‐carbon and amide nitrogen such as poly( N ‐methyl L‐alanine) (PNMA) has an additional feature for the conformation, that is well‐defined secondary structure based on all‐trans peptide configurations . For example, Imanishi et al reported the effect of N ‐substituted polypeptide on the polymerization of NCA as polymer catalysts using these features …”

Polypeptoids: A perfect match for molecular definition and macromolecular engineering?

“…l ‐Proline or hydroxyproline units are also critically influencing the secondary structure formation in proteins . The ring constraint found in proline is not responsible for the secondary structure formation as similar helices are found for acyclic polyiminoacids, such as poly(N‐methyl‐alanine) or poly(ɣ‐ethyl N‐methyl‐ l ‐glutamate) . In the case of polypeptoids, Sisido et al have found a marked flexibility in the backbone and that, in contrast to polypeptides, both cis and trans conformation of the backbone are significantly populated .…”

Insight into the synthesis of N-methylated polypeptides

“…The results have strong similarities to previous studies by Cosani et al where they observed similar values (min(θ MR ) = 228 nm; max(θ MR ) = 196 nm) for poly(N-methylγ-methyl-L-glutamate) and poly(N-methyl-γ-ethyl-L-glutamate) in TFE. 25 Along with conformational studies on poly(N-methyl-L-alanine), carried out by Goodman et al, the authors proposed a right-handed helix as the secondary structure. 18 Despite a small blue shift of 1-2 nm for both bands ( positive…”

“…24 Like poly(N-methyl-L-alanine), both polymers were found to form a right-handed helix in a TFE solution of remarkably high stability, which retained their conformation even in pure TFA as observed by CD (circular dichroism) measurements. 25 A special case is the amino acid proline, the only proteinogenic amino acid containing a secondary amine. Poly(L-proline) (PLP) can form a right-handed PLP I helix (cis) in aliphatic alcohols and a left-handed PLP II helix (trans) in water and organic acids.…”