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Collagen is the most abundant protein in humans. It has a characteristic triple-helix structure and is heavily posttranslationally modified. The complex biosynthesis of collagen involves processing by many enzymes and chaperones in the rough endoplasmic reticulum. Lysyl hydroxylase 1 (LH1) is required to hydroxylate lysine for cross-linking and carbohydrate attachment within collagen triple helical sequences. Additionally, a recent study of prolyl 3-hydroxylase 3 (P3H3) demonstrated that this enzyme may be critical for LH1 activity; however, the details surrounding its involvement remain unclear. If P3H3 is an LH1 chaperone that is critical for LH1 activity, P3H3 and LH1 null mice should display a similar deficiency in lysyl hydroxylation. To test this hypothesis, we compared the amount and location of hydroxylysine in the triple helical domains of type V and I collagen from P3H3 null, LH1 null, and wild-type mice. The amount of hydroxylysine in type V collagen was reduced in P3H3 null mice, but surprisingly type V collagen from LH1 null mice contained as much hydroxylysine as type V collagen from wild-type mice. In type I collagen, our results indicate that LH1 plays a global enzymatic role in lysyl hydroxylation. P3H3 is also involved in lysyl hydroxylation, particularly at cross-link formation sites, but is not required for all lysyl hydroxylation sites. In summary, our study suggests that LH1 and P3H3 likely have two distinct mechanisms to recognize different collagen types and to distinguish cross-link formation sites from other sites in type I collagen.

Since the triple-helical collagen model peptides with a free N-terminus have three cationic groups at one end, it may have strong interactions with polyelectrolytes. In this study, complex formation behavior was investigated for sodium carboxymethyl amylose (NaCMA) + H-(Pro-Pro-Gly)10-OH (PPG10), a collagen model peptide, in aqueous NaCl with ionic strength of 10 mM and 100 mM by means of small-angle X-ray scattering (SAXS) and circular dichroism at different temperatures. The previously reported [Macromolecules2012, 45, 392–400] sodium polyacrylate (NaPAA) and H-(Gly-Pro-4-(R)-Hyp)9-OH (GPO9) system was also investigated to elucidate complex formation nearby the transition temperature region between triple helix and single coil of the peptide. The complex formed near the melting temperature of the triple helices, confirmed that the triple helical structure is directly related to the complex formation.

THE TWENTY-FOURTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL LIFE AND ROBOTICS (AROB 24th 2019),January 23-25, 2019, B-Con Plaza, Beppu, JAPAN

Terao K., Kanenaga R., Sato T., et al. Complex formation of collagen model peptides with polyelectrolytes and stabilization of the triple helical structure. Macromolecules, 45(1), 392-400, December 7, 2011. Copyright © 2011, American Chemical Society. https://doi.org/10.1021/ma202176w., Small-angle X-ray scattering (SAXS) measurements were made for three collagen model peptides, H-(Gly-Pro-4-(R)-Hyp) 9-OH, H-(Pro-4-(R)-Hyp-Gly) 9-OH, and H-(Gly-4-(R)-Hyp-4-(R)-Hyp) 9-OH with or without sodium polyacrylate (NaPAA) in 20 mM and 100 mM aqueous NaCl at 15 and 75 °C. At 15 °C, almost all triple helical peptides form a complex with NaPAA when the molar ratio of acrylic acid unit to peptide molecules is larger than 10 whereas they are molecularly dispersed at 75 °C. Furthermore, the attached triple helices appreciably extend the main chain of NaPAA, and the radius of gyration for the complex is at most twice larger than the single NaPAA chain. Circular dichroism measurements demonstrated that the complexation noticeably stabilizes the triple helical structure and the melting midpoint temperature T m is 2-10 °C higher than that for the solution without NaPAA. This stabilization was also observed for negatively charged sodium carboxymethylamylose and sodium hyaluronate as well as for positively charged poly(vinyl ammonium) chloride, but no appreciable stabilization of the triple helical structure by the polyelectrolytes was observed for an end-capped peptide Ac-(Gly-Pro-4-(R)-Hyp) 9-NH 2. These results indicate that the complex formation is due to the electrostatic attraction between polyelectrolytes and the opposite charges at the end of uncapped triple helical peptides. © 2011 American Chemical Society.

Terao K., Mizuno K., Murashima M., et al. Chain dimensions and hydration behavior of collagen model peptides in aqueous solution: [Glycyl-4(R)-hydroxyprolyl-4(R)-hydroxyproline]n, [Glycylprolyl-4(R)-hydroxyproline]n, and some related model peptides. Macromolecules, 41(19), 7203-7210, September 4, 2008. Copyright © 2008, American Chemical Society. https://doi.org/10.1021/ma800790w., Small-angle X-ray scattering (SAXS), circular dichroism (CD), and density measurements were made on eight samples of collagen model peptides consisting of glycine (Gly), proline (Pro), and 4-(R)-hydroxyproline (Hyp), i.e., (Gly-Hyp-Hyp)n, (Gly-Pro-Hyp)n, (Gly-Hyp-Pro)n, and (Gly-Pro-Pro)n (n = 5 and 9) in pure water and in phosphate buffered saline at a wide range of temperatures between 4 and 75°C. A complete triple-helical structure was found only for (Gly-Hyp-Hyp)9 and (Gly-Pro-Hyp)9 at 15°C by SAXS and CD, and (Gly-Pro-Pro) 9 had a partially formed triple helix at 4°C. At 70°C or higher temperatures, all peptides are dispersed as monomeric chains in these solvents and have essentially the same radii of gyration as the literature values for denatured proteins with the equivalent number of amino acid residues, suggesting that the conformational entropy for the single chain of the collagen model peptides is almost independent of the imino acid content. Furthermore, the partial specific volume v̄ for (Gly-Hyp-Hyp)9 around the transition temperature decreases more gradually with decreasing temperature than that for (Gly-Hyp-Hyp)5. On the contrary, the temperature dependence of v̄ for (Gly-Pro-Hyp)n has the opposite tendency, indicating that the hydration number for the peptide (Gly-Pro-Hyp)9 increases with formation of the triple helix whereas that for the peptide (Gly-Hyp-Hyp)9 decreases. These results are consistent with the difference in the transition enthalpies reported previously [J. Biol. Chem. 2004, 279, 38072]. © 2008 American Chemical Society.

直接基礎に摩擦杭を併用したパイルド・ラフト基礎の沈下挙動に関する解析法は、その多くが地盤を基礎構造物に外力を及ぼすものと捉え、基礎構造物自身を解くものである。本論文では、土骨格の変位場に制約条件を設定してパイルド・ラフト基礎の働きを表現し、水～土連成場で地盤に関する力のつり合い式を解く。これによりパイルド・ラフト基礎が設置された弾塑性地盤の圧密沈下特性と荷重伝達機構を調べ、以下の点が明らかになった。①上載荷重を杭先端以深の地盤の深部に伝達することで沈下量を低減できる。②地盤の透水係数によらず沈下量を低減できる。③偏荷重による不同沈下量の低減には有効であるが、杭先端が傾斜した基盤部付近まで達するような場合は、不同沈下量の低減に効果がない場合がある。, In this research the deformation characteristics and load transfer behavior of a piled raft in the elastoplastic ground are studied using soil-water coupled deformation analysis. The plane strain piled raft is simulated introducing some linear constraint conditions over the velocity field. The piled raft reduces the final settlement significantly. This reduction is due to the load transfer through shear by piles into deeper soil layers which disperses the induced stresses compared with only the raft. The settlement of a piled raft is not affected by the permiability of ground. Further, the piled raft induces homogeneous settlement even with eccentric loading, however, this is not effective for a ground with an inclined bed rock.