Site Specific Interactions and Collagen Self Assembly

蛋白质自组装成大分子的能力是所有生物体的基础。这些结构中最复杂的一些是由三螺旋胶原形成的原纤维。单体自组装成原纤维的精确方式尚未确定。本申请基于我们的观察，即胶原蛋白I的端肽结合到α 1（1）链的跨越氨基酸776至822的特定区域，并且这种相互作用对于胶原蛋白自组装是关键的。我们最近的胶原蛋白I和胶原蛋白II突变体的组装结果，强烈支持我们的假设，即胶原蛋白分子之间的位点特异性相互作用是至关重要的原纤维形成。我们现在使用基因工程胶原II和胶原IX来详细研究同型和异型纤维形成的机制。该项目的广泛，长期目标是了解健康和疾病中胶原纤维形成的基本原则。总的假设是，在原纤维组装过程中胶原单体之间的特异性相互作用是由端肽与三螺旋结构域的特定区域的结合控制的。这种结合对于调节胶原原纤维形成至关重要。此外，我们假设异型原纤维的组装也受到位点特异性形成的控制。此外，我们假设异型原纤维的组装也是由不同胶原类型之间的位点特异性相互作用控制的，并且原纤维胶原中的突变改变了位点特异性相互作用，因此改变了细胞外基质的结构。为了检验这些假设，提出了以下具体目标：（1）阐明同型和异型胶原原纤维形成的位点特异性机制，（2）确定胶原分子之间的位点特异性相互作用如何调节原纤维的形态、胶原自组装的动力学和热力学，（3）分析纤维状胶原的突变如何影响胶原组装的位点特异性机制。该研究将为胶原纤维的自组装结构提供新的信息。建议的研究结果将在胶原纤维发挥重要作用的领域有广泛的应用。实例包括细胞分化和增殖、发育、骨矿化、组织重塑、纤维化、组织工程和结缔组织的遗传性疾病的治疗。

The ability of proteins to self-assemble into macromolecules is fundamental to all living organisms. Some of the most complex of these structures are the fibrils formed from the triple helical collagen. The precise manner in which the monomers self-assemble into fibrils has not been defined. The present application is based on our observations that the telopeptides of collagen I bind to a specific region spanning amino acids 776 to 822 of the alpha1(1) chain, and that this interaction is critical for collagen self-assembly. Our recent results of the assembly of collagen I and collagen II mutants, strongly support our hypothesis that site-specific interactions between collagen molecules are critical for the fibril formation. We now use the gene-engineered collagen II and collagen IX to study the mechanism of the formation of homotypic and heterotypic fibrils in detail. The broad, long-term goal of this project is to understand fundamental principles of the formation of collagen fibrils in health and disease. The overall hypothesis is that the specific interaction between collagen monomers during fibril assembly is controlled by the binding of telopeptides to specific regions of the triple- helical domain. This binding is critical for the regulation of collagen fibril formation. Moreover, we hypothesize that assembly of heterotypic fibrils is also controlled by the site-specific formation. Moreover we hypothesize that assembly of heterotypic fibrils is also controlled by the site-specific interactions between different collagen types, and that mutations in fibrillar collagens change the site-specific interaction and, as a result, alter the structure of the extracellular matrix. To test the hypotheses, the following specific aims are proposed: (1) To elucidate a site-specific mechanism of the formation of homotypic and heterotypic collagen fibrils, (2) To determine how the site-specific interactions between collagen molecules regulate morphology of fibrils, kinetics and thermodynamics of collagen self-assembly, and (3) To analyze how mutations in fibrillar collagens affect the site-specific mechanism of collagen assembly. The proposed research will yield new information on collagen self-assembly structure of collagen fibrils. Results of the proposed studies will have a wide application in the areas where collagen fibrils play an important role. Examples include cell differentiations and proliferations, development, bone mineralization, tissue remodeling, fibrosis, tissue engineering, and therapy of the heritable diseases of connective tissue.