Self-Assembled α-Helical Polypeptide Films

• Main Authors: Enriquez, Erwin, Samulski, Edward T
• Format: text
• Published: Archīum Ateneo 1991
• Subjects: Chemistry; Polymer Chemistry
• Online Access: https://archium.ateneo.edu/chemistry-faculty-pubs/55; https://www.cambridge.org/core/journals/mrs-online-proceedings-library-archive/article/selfassembled-helical-polypeptide-films/B0B5B5154B96606D81192B1A804E1FE5
• Institution: Ateneo De Manila University

Poly(γ-benzyl-L-glutamate) (PBLG) derivatized at its N-terminus with lipoic acid, a disulfide-containing moiety, self-assembles on gold from helicogenic solvents to give a thin film with the polypeptide α-helices orientation distribution different from the planar orientation in the unlabeled, physisorbed PBLG films (control) and Langmuir-Blodgett monolayers. The SA films were studied by angle-dependent XPS, reflection-absorption FTIR spectroscopy, and ellipsometry. The IR dichroic properties of the amide I and amide II bands were used to infer the orientational distribution of the helices in the self-assembled film and lead to two extreme pictures of the helix axis distribution function: (a) random (hemispherical distribution) and (b) perfect order with a tilt of 53° from the surface normal. Additional characterization is necessary to differentiate between these two distributions.