Far-infrared spectra of polyalanines with α-helical and β-form structures

✍ Scribed by K. Itoh; T. Nakahara; T. Shimanouchi; M. Oya; K. Uno; Y. Iwakura

• Publisher: Wiley (John Wiley & Sons)
• Year: 1968
• Tongue: English
• Weight: 384 KB
• Volume: 6
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1968.360061211

✦ Synopsis

Far-infrared spectra of poly-palanines having the a-helical conformation and the ,%form structure were measured. The spectra of glycine-L-alanine copolymer, silk fibroin, and copoly-D,calanines with different D : L compositions were also measured. In addition to the bands so far reported, four bands at 190, 167, 120, and 90 cm-1 were found for the a-helix conformation and the two bands at 442 and 247 cm-1 were found for the 6 form. The 442 cm-l band consists of the parallel 432 cm-l and perpendicular 445 cm-1 bands. The 247 cm-1 band is well defined and has strong dichroism parallel to the direction of stretching. These two bands appear also for silk fibroin and glycine-L-alanine copolymer. All the far-infrared bands of copoly-D,talanines can be interpreted as a-helix bands, the three peaks at 580, 478, and 420 cm-I being ascribed to the D-residue incorporated into the right-handed a-helix or to the tresidue in the left-handed a-helix.