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Synthesis of poly(Pro–Hyp–Gly) n by direct polycondensation of (Pro–Hyp–Gly) n , where n = 1, 5, and 10, and stability of the triple‐helical structure
Author(s) -
Kishimoto Takahiro,
Morihara Yasushi,
Osanai Michinori,
Ogata Shinichi,
Kamitakahara Masanobu,
Ohtsuki Chikara,
Tanihara Masao
Publication year - 2005
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.20348
Subject(s) - chemistry , carbodiimide , fourier transform infrared spectroscopy , polymerization , peptide , condensation polymer , side chain , amino acid , crystallography , hydrochloride , stereochemistry , polymer chemistry , polymer , organic chemistry , biochemistry , physics , quantum mechanics
Pro–Hyp–Gly is a characteristic amino acid sequence found in fibrous collagens, and (Pro–Hyp–Gly) 10 , which has been widely used as a collagen‐model peptide, forms a stable triple‐helical structure. Here, we synthesized polypeptides consisting of the Pro–Hyp–Gly sequence by direct polycondensation of (Pro–Hyp–Gly) n , where n = 1, 5, and 10, using 1‐hydroxybenzotriazole and 1‐ethyl‐3‐(3‐dimethyl‐aminopropyl)‐carbodiimide hydrochloride in both phosphate buffer (pH = 7.4) and dimethylsulfoxide (DMSO) solutions for 48 h at 20°C. The reaction of (Pro–Hyp–Gly) 5 and (Pro–Hyp–Gly) 10 in DMSO successfully gave polypeptides with molecular weights over 10,000, whereas low molecular weight products were obtained by reaction in phosphate buffer (pH = 7.4). In contrast, Pro–Hyp–Gly at a concentration of 50 mg/mL in phosphate buffer (pH = 7.4) gave polypeptides with molecular weights over 10,000. The Fourier transform infrared (FTIR) and 1 H nuclear magnetic resonance (NMR) spectra of poly(Pro–Hyp–Gly) 10 revealed that the polymerization of (Pro–Hyp–Gly) 10 described in this report had no side reactions. Each polypeptide obtained shows a collagen‐like triple‐helical structure, and the triple‐helical structures of poly(Pro–Hyp–Gly) and poly(Pro–Hyp–Gly) 10 were stable up to T = 80°C, which suggests that the high molecular weight promotes stability of the triple‐helical structure, in addition to the high Hyp content. Furthermore, transmission electron microscopy (TEM) observations show that poly(Pro–Hyp–Gly) 10 aggregates to form nanofiber‐like structures about 10 nm in width, which suggests that a Pro–Hyp–Gly repeating sequence contains enough information for triple‐helix formation, and for subsequent nanofiber‐like structure formation. © 2005 Wiley Periodicals, Inc. Biopolymers 79: 163–172, 2005 This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com