文章基本信息

标题：Proline provides site-specific flexibility for in vivo collagen
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作者：Wing Ying Chow ; Chris J. Forman ; Dominique Bihan 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2018
卷号：8
期号：1
页码：13809
DOI：10.1038/s41598-018-31937-x
语种：English
出版社：Springer Nature
摘要：Fibrillar collagens have mechanical and biological roles, providing tissues with both tensile strength and cell binding sites which allow molecular interactions with cell-surface receptors such as integrins. A key question is: how do collagens allow tissue flexibility whilst maintaining well-defined ligand binding sites? Here we show that proline residues in collagen glycine-proline-hydroxyproline (Gly-Pro-Hyp) triplets provide local conformational flexibility, which in turn confers well-defined, low energy molecular compression-extension and bending, by employing two-dimensional ¹³C-¹³C correlation NMR spectroscopy on ¹³C-labelled intact ex vivo bone and in vitro osteoblast extracellular matrix. We also find that the positions of Gly-Pro-Hyp triplets are highly conserved between animal species, and are spatially clustered in the currently-accepted model of molecular ordering in collagen type I fibrils. We propose that the Gly-Pro-Hyp triplets in fibrillar collagens provide fibril “expansion joints” to maintain molecular ordering within the fibril, thereby preserving the structural integrity of ligand binding sites.