Haston J Louise, Engelsen Soren B, Roessle Manfred, Clarkson John, Blanch Ewan W, Baldock Clair, Kielty Cay M, Wess Timothy J
Department of Biological Sciences, University of Stirling, Stirling FK9 4LA, United Kingdom.
J Biol Chem. 2003 Oct 17;278(42):41189-97. doi: 10.1074/jbc.M212854200. Epub 2003 Jul 21.
Fibrillin-rich microfibrils are essential elastic structures contained within the extracellular matrix of a wide variety of connective tissues. Microfibrils are characterized as beaded filamentous structures with a variable axial periodicity (average 56 nm in the untensioned state); however, the basis of their elasticity remains unknown. This study used a combination of small angle x-ray scattering and Raman microscopy to investigate further the packing of microfibrils within the intact tissue and to determine the role of molecular reorganization in the elasticity of these microfibrils. The application of relatively small strains produced no overall change in either molecular or macromolecular microfibrillar structure. In contrast, the application of larger tissue extensions (up to 150%) resulted in a markedly different structure, as observed by both Raman microscopy and small angle x-ray scattering. These changes occurred at different levels of architecture and are interpreted as ranging from alterations in peptide bond conformation to domain rearrangement. This study demonstrates the importance of molecular elasticity in the mechanical properties of fibrillin-rich microfibrils in the intact tissue.
富含原纤蛋白的微原纤维是多种结缔组织细胞外基质中必不可少的弹性结构。微原纤维的特征是具有可变轴向周期性（在未拉伸状态下平均为56纳米）的串珠状丝状结构；然而，其弹性的基础仍然未知。本研究结合小角X射线散射和拉曼显微镜技术，进一步研究完整组织内微原纤维的堆积情况，并确定分子重组在这些微原纤维弹性中的作用。施加相对较小的应变不会使分子或大分子微原纤维结构发生整体变化。相比之下，通过拉曼显微镜和小角X射线散射观察发现，施加较大的组织延伸（高达150%）会导致明显不同的结构。这些变化发生在不同的结构层次，被解释为从肽键构象的改变到结构域重排。本研究证明了分子弹性在完整组织中富含原纤蛋白的微原纤维力学性能中的重要性。
