title: Physical Gelation of α-Helical Copolypeptides.
abstract: Owing to its rod-like α-helical secondary structure, the synthetic polypeptide poly(γ-benzyl-l-glutamate) (PBlG) can form physical and thermoreversible gels in helicogenic solvents such as toluene. The versatility of PBlG can be increased by introducing functionalizable comonomers, such as allylglycine (AG). In this work we examined the secondary structure of PBlG and a series of statistical poly(γ-benzyl-l-glutamate-co-allylglycine) copolypeptides, varying in composition and chain length, by circular dichroism (CD), Fourier-transform infrared (FTIR) and Raman spectroscopy, and wide-angle X-ray scattering (WAXS). The secondary structure of PBlG and the copolypeptides presented dissimilarities that increased with increasing AG molar fraction, especially when racemic AG units were incorporated. The physical gelation behavior of these copolypeptides was analyzed by temperature-sweep (1)H NMR and rheological measurements. The study revealed that both copolypeptide composition and chain length affected secondary structure, gelation temperature, and gel stiffness.
authors.affiliation: Max Planck Institute of Colloids and Interfaces , Department of Colloid Chemistry, Research Campus Golm, 14424 Potsdam, Germany.
authors.forename: Charlotte D
authors.initials: CD
authors.lastname: Vacogne
authors.affiliation: Waters GmbH, TA Instruments, Helfmann-Park 10, 65760 Eschborn, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schopferer
authors.affiliation: University of Potsdam , Institute of Chemistry, Karl-Liebknecht-Straße 24-25, 14476 Potsdam, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Schlaad
mesh_terms: D002942:Circular Dichroism; D005782:Gels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D010455:Peptides / Q000737:chemistry*; D011099:Polyglutamic Acid / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D000072756:Protein Conformation, alpha-Helical
chemical_list: D005782:Gels; D010455:Peptides; D011108:Polymers; D011099:Polyglutamic Acid