title: Polymorphism of collagen triple helix revealed by 19F NMR of model peptide [Pro-4(R)-hydroxyprolyl-Gly]3-[Pro-4(R)-fluoroprolyl-Gly]-[Pro-4(R)-hydroxyprolyl-Gly]3.
abstract: We have characterized various structures of (Pro-Hyp(R)-Gly)(3)-Pro-fPro(R)-Gly-(Pro-Hyp(R)-Gly)(3) in the process of cis-trans isomerization and helix-coil transition by exploiting the sole (19)F NMR probe in 4(R)-fluoroproline (fPro(R)). Around the transition temperature (T(m)), we detected a species with a triple helical structure distinct from the ordinary one concerning the alignment of three strands. The (19)F-(19)F exchange spectroscopy showed that this misaligned and that the ordinary triple helices were interchangeable only indirectly via an extended monomer strand with all-trans peptide bonds at Pro-fPro(R), Pro-Hyp(R), and Gly-Pro in the central segment. This finding demonstrates that the helix-coil transition of collagen peptides is not described with a simple two-state model. We thus elaborated a scheme for the transition mechanism of (Pro-Hyp(R)-Gly)(n) that the most extended monomer strand can be the sole source both to the misaligned and correctly folded triple-helices. The staggered ends could help misaligned triple helices to self-assemble to higher-order structures. We have also discussed the possible relationship between the misaligned triple helix accumulating maximally at T(m) and the kinetic hysteresis associated with the helix-coil transition of collagen.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kawahara
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Nemoto
authors.forename: Daisuke
authors.initials: D
authors.lastname: Motooka
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Nishi
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Doi
authors.forename: Susumu
authors.initials: S
authors.lastname: Uchiyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakazawa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nishiuchi
authors.forename: Takuya
authors.initials: T
authors.lastname: Yoshida
authors.forename: Tadayasu
authors.initials: T
authors.lastname: Ohkubo
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kobayashi
mesh_terms: D003094:Collagen / Q000737:chemistry* / Q000235:genetics; D005462:Fluorine Radioisotopes / Q000737:chemistry; D007700:Kinetics; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D017433:Protein Structure, Secondary; D013237:Stereoisomerism; D013696:Temperature
chemical_list: C576016:(Pro-4(R)-hydroxyprolyl-Gly)3-(pro-4(R)-fluoroprolyl-Gly)-(Pro-4(R)-hydroxyprolyl-Gly)3; D005462:Fluorine Radioisotopes; D010455:Peptides; D003094:Collagen