title: Synthesis of poly(Pro-Hyp-Gly)(n) by direct poly-condensation of (Pro-Hyp-Gly)(n), where n=1, 5, and 10, and stability of the triple-helical structure.
abstract: 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 poly-condensation 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 degrees 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 degrees 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.
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, IkomaNara 630-0192, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kishimoto
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Morihara
authors.forename: Michinori
authors.initials: M
authors.lastname: Osanai
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Ogata
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kamitakahara
authors.forename: Chikara
authors.initials: C
authors.lastname: Ohtsuki
authors.forename: Masao
authors.initials: M
authors.lastname: Tanihara
mesh_terms: D000595:Amino Acid Sequence; D002021:Buffers; D002850:Chromatography, Gel; D002942:Circular Dichroism; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004355:Drug Stability; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000031:analogs & derivatives / Q000494:pharmacology; D005029:Ethylenediamines / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008854:Microscopy, Electron; D008970:Molecular Weight; D019906:Nuclear Magnetic Resonance, Biomolecular; D009842:Oligopeptides / Q000138:chemical synthesis*; D010316:Particle Size; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D013696:Temperature; D014230:Triazoles / Q000494:pharmacology
chemical_list: D002021:Buffers; D005029:Ethylenediamines; D009842:Oligopeptides; D010455:Peptides; D014230:Triazoles; C083881:(prolyl-hydroxylprolyl-glycine)10; C031234:ethylenediamine; C041829:1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide methiodide; C011852:1-hydroxybenzotriazole; D005022:Ethyldimethylaminopropyl Carbodiimide; D004121:Dimethyl Sulfoxide