Structural bases of ADAMTS-13 and VWF A2 interactions

描述（由申请人提供）：本研究将作为NIH基金R01 HL093723- 01A1的延伸，与楼继忠教授合作，主要在中国北京中国科学院生物物理研究所进行。这个FIRCA申请有一个应有的目标：1)扩大和提高家长资助，2)提高楼继忠博士团队的研究能力。本研究的目的是阐明血管性血友病因子和ADAMTS- 13之间的分子相互作用的机械调控，这是生理止血和病理性血栓形成的关键相互作用。相互作用的功能障碍可能导致血管性血友病和血栓性血小板减少性紫癜。ADAMTS- 13/VWF的相互作用在循环的流体动力环境中受到机械调节。我们对这项FIRCA授权的假设是水动力诱导VWF A2结构域展开，促进其与ADAMTS-13的相互作用，与ADAMTS-13的结合也会导致ADAMTS-13的构象变化，以实现有效的蛋白质水解，构象受A2展开程度和机械力的调节。这一广泛的假设将在两个具体目标中得到验证：1)通过比较野生型（WT） VWF A2结构域和一组突变型VWF A2结构域的力和热诱导展开途径来阐明2A型VWD的结构机制；建立ADAMTS-13/A2相互作用的原子模型，并确定这些相互作用如何调节A2展开和ADAMTS-13构象变化。这些具体目标是计算性研究，是对父母补助金的补充。在FIRCA基金中提出的分子动力学模拟和分子建模将有助于解释从上级基金中获得的实验数据，并为设计新的实验提供机会，以测试上级基金和FIRCA基金的整体假设。破译机械力如何调节VWF A2展开，ADAMTS-13构象以及两个分子之间的相互作用将为血管生理学和病理学提供关键见解。因此，这些数据可能为相关疾病提供新的治疗方法。

DESCRIPTION (provided by applicant): This research will be done primarily at Institute of Biophysics, Chinese Academy of Sciences in Beijing, China in collaboration with Professor Jizhong Lou as an extension of NIH grant R01 HL093723- 01A1. This FIRCA application has a due objective: 1) to expand and enhance the parent grant and 2) to increase the research capacity of Dr. Jizhong Lou's group. The goal of this and the parent proposal is to elucidate the mechanical regulation of molecular interactions between von Willebrand factor and ADAMTS- 13, which are key interactions on physiological hemostasis and pathological thrombosis. Malfunction in the interactions may lead to von Willebrand disease and thrombotic thrombocytopenic purpura. ADAMTS- 13/VWF interaction is regulated mechanically as they take place in the hydrodynamic environment of the circulation. Our hypothesis for this FIRCA grant is that hydrodynamic forces induce the unfolding of VWF A2 domain which promotes its interactions to ADAMTS-13, the binding with ADAMTS-13 will also lead to the conformational changes on ADAMTS-13 for efficient proteolysis and the conformations are regulated by the degree of A2 unfolding and mechanical forces. The broad hypothesis will be tested in two specific aims: 1) Elucidate the structural mechanisms of type 2A VWD by comparing the force- and thermo-induced unfolding pathways of wild-type (WT) VWF A2 domain and a panel of mutant VWF A2 domains, and 2) 2.Develop atomic models for the ADAMTS-13/A2 interactions and determine how these interactions regulate A2 unfolding and ADAMTS-13 conformational changes. These specific aims are computational studies, which complement the parent grant. The molecular dynamics simulations and molecular modeling proposed in the FIRCA grant will help to interpret the experimental data obtained from the parent grant and provide opportunities to design new experiments to test the overall hypothesis of the parent and the FIRCA grant. Decoding how mechanical forces regulate VWF A2 unfolding, ADAMTS-13 conformations and the interactions between the two molecules will provide key insights into vascular physiology and pathology. As a result, the data may office new therapeutic approaches to relevant diseases. PUBLIC HEALTH RELEVANCE: This FIRCA proposal extends the parent grant in several ways. Information obtained from the parent and this FIRCA grants will help develop new therapeutic approaches to type 2A von Willebrand disease and thrombotic thrombocytopenic purpura.