Conformational change of the triple-helical structure. II. Conformation of (Pro-Pro-Gly)n and (Pro-Pro-Gly)n(Ala-Pro-Gly)m(Pro-Pro-Gly)n in an aqueous solution

✍ Scribed by Kazuo Sutoh; Haruhiko Noda

• Publisher: Wiley (John Wiley & Sons)
• Year: 1974
• Tongue: English
• Weight: 678 KB
• Volume: 13
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1974.360131118

✦ Synopsis

Measurements of the molecular weight of (Pro-Pro-Gly), and (Pro-Pro-Gly),(Ala-Pro-Gly),(Pro-Pro-Gly),, which were synthesized by the solid-phase method, revealed that they formed a trimer in an aqueous solution, and dissociated into single-stranded chains on warming. Accompanying the transition, a large decrease of optical rotation was observed, like the collagen-gelatin transition. The shape of the trimeric molecule was rodlike, and the dimensions were 12 per residue in length, regardless of the length of Ala-Pro-Gly sequences in a peptide chain. The data indicate that both Pro-Pro-Gly sequences and Ala-Pro-Gly sequences form the triple-helical structure similar to that of collagen in aqueous solution. All optical rotational dispersion (ORD) curves of solutions of the peptides were represented by a single-term Drude equation, and the Drude constant xc was 200 nm for all peptides regardless of the length of Ala-Pro-Gly sequences. The resemblance between the helical structure formed by Pro-Pro-Gly sequences and that by Ala-Pro-Gly sequences was also suggested by the formation of the hybrid triple helix from two kinds of peptide chains with different lengths of Ala-Pro-Gly sequences. in diameter and 2.8