Poly(2-acrylamido-2-methyl-1-propanamide) (PAMPA): A neutral, water-soluble synthetic polymer with double-stranded helix conformation
Wang J., Meersman F., Esnouf R., Froeyen M., Busson R., Heremans K., Herdewijn P.
A new synthetic polymer, poly(2-acrylamido-2-methyl-1-propanamide) (PAMPA), is described. It combines the structural features of poly(leucine) and poly(glutamine), its molecular weight averages 42000 D, and it contains ca. 270 residues. A 13 C-NMR-tacticity study indicates that it consists of a mixture of syndiotactic (38%), heterotactic (48%), and isotactic (17%) polymer. PAMPA has a tendency to self-organize into a coiled-coil double-stranded helix structure in aqueous solution, as determined by Fourier-transform infrared spectroscopy (FT-IR). Molecular modeling of PAMPA shows that the helix formation is driven by repeated intramolecular H-bonds between nearest-neighbor amide groups, and that the structure is further stabilized by hydrophobic interactions between the two lateral Me groups. PAMPA has a neutral structure, is highly water-soluble, and demonstrates temperature stability.