Kwansa Albert L, De Vita Raffaella, Freeman Joseph W
Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA 24061, USA; Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA 24061, USA.
Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA 24061, USA.
Biophys Chem. 2016 Jul-Aug;214-215:1-10. doi: 10.1016/j.bpc.2016.04.001. Epub 2016 Apr 19.
Collagen type I crosslink type and prevalence can be influenced by age, tissue type, and health; however, the role that crosslink chemical structure plays in mechanical behavior is not clear. Molecular dynamics simulations of ~65-nm-long microfibril units were used to predict how difunctional (deH-HLNL and HLKNL) and trifunctional (HHL and PYD) crosslinks respond to mechanical deformation. Low- and high-strain stress-strain regions were observed, corresponding to crosslink alignment. The high-strain elastic moduli were 37.7, 37.9, 39.9, and 42.4GPa for the HLKNL, deH-HLNL, HHL, and PYD-crosslinked models, respectively. Bond dissociation analysis suggests that PYD is more brittle than HHL, with deH-HLNL and HLKNL being similarly ductile. These results agree with the tissues in which these crosslinks are found (e.g., deH-HLNL/HLKNL in developing tissues, HHL in mature skin, and PYD in mature bone). Chemical structure-function relationships identified for these crosslinks can aid the development of larger-scale models of collagenous tissues and materials.
I型胶原蛋白的交联类型和发生率会受到年龄、组织类型和健康状况的影响；然而，交联化学结构在力学行为中所起的作用尚不清楚。利用约65纳米长的微原纤维单元的分子动力学模拟来预测双功能交联（去氢-羟基赖氨酸-正亮氨酸-赖氨酸和羟基赖氨酸-赖氨酸-正亮氨酸-赖氨酸）和三功能交联（羟赖氨酸-羟赖氨酸-亮氨酸和吡啶啉）如何响应机械变形。观察到了对应于交联排列的低应变和高应变应力-应变区域。对于羟基赖氨酸-赖氨酸-正亮氨酸-赖氨酸、去氢-羟基赖氨酸-正亮氨酸-赖氨酸、羟赖氨酸-羟赖氨酸-亮氨酸和吡啶啉交联模型，高应变弹性模量分别为37.7、37.9、39.9和42.4吉帕。键解离分析表明，吡啶啉比羟赖氨酸-羟赖氨酸-亮氨酸更脆，而去氢-羟基赖氨酸-正亮氨酸-赖氨酸和羟基赖氨酸-赖氨酸-正亮氨酸-赖氨酸的韧性相似。这些结果与发现这些交联的组织情况相符（例如，发育中的组织中有去氢-羟基赖氨酸-正亮氨酸-赖氨酸/羟基赖氨酸-赖氨酸-正亮氨酸-赖氨酸，成熟皮肤中有羟赖氨酸-羟赖氨酸-亮氨酸，成熟骨骼中有吡啶啉）。为这些交联确定的化学结构-功能关系有助于开发更大规模的胶原组织和材料模型。
