Controlling Enzyme Structure and Activity with Light Illumination

纳米技术隐含在将蛋白质组装成人体中普遍存在的数千种活性纳米结构的过程中。蛋白质作为这些生物异常机器的构建模块的效用源于这样一个事实：蛋白质是动态实体，以独特而复杂的方式响应分子相互作用，通常导致各种非天然或相关状态的构象变化。这些构象转变几乎影响到每一个生物过程。因此，需要了解在各种刺激下形成的非原生状态的结构以及这些状态之间重新排列的动态。这就需要一种快速诱导蛋白质构象变化的方法和一种以相对高分辨率确定非天然状态（部分折叠或相关）结构的方法。南加州大学的C. Ted Lee, Jr.计划利用光反应表面活性剂诱导蛋白质展开或结合来实现这一目标，这将通过小角度中子散射（SANS）来检测。表面活性剂通常通过破坏分子内或分子间氨基酸的接触来影响蛋白质的构象，分别导致蛋白质展开或蛋白质聚集体的解离。然而，在光反应性表面活性剂的情况下，表面活性剂-氨基酸结合可以通过简单的光照打开或关闭。这种光控制蛋白质构象的新方法将在几个长度尺度上进行研究。利用SANS通过形状重建计算方法确定蛋白质的三级和四级结构，以最佳地拟合散射数据，从而确定体外蛋白质结构。SANS实验要求分配来自国家实验室的竞争光束时间。该提案要求拨款，允许在今年10月14日至17日期间在橡树岭国家实验室的bioSANS仪器上收集SANS数据，并由李氏集团的一名研究生参与。这些实验将允许充分表征光控原生到中间到变性或单体到聚集的蛋白质转变。更广泛的影响。允许研究生访问ORNL三天将提供宝贵的经验。事实上，由于类似的访问，PI以前的一名学生现在在NIST工作。化学工程教育面临着与教师研究越来越脱节的课程设置。为了缩小这一差距，像这个旅行奖这样的提议将允许学生在实验室的氛围中工作，并最终与课程的特点联系起来。

Nanotechnology is implicit in the assembly of proteins into the thousands of active nanostructures pervasive in the human body. The utility of proteins as the building blocks of these bionanomachines derives from the fact that proteins are dynamic entities, responding to molecular interactions in unique and complex ways, often resulting in conformation changes to various non-native or associated states. These conformational transitions influence virtually every biological process. As such, knowledge of both the structure of the non-native states that form in response to various stimuli along with the dynamics of rearrangements between these states is required. This necessitates a means to rapidly induce changes in protein conformation and a method to determine the structure of non-native states (partially-folded or associated) at relatively high resolution. C. Ted Lee, Jr. of the University of Southern California plans to achieve this goal using light-responsive surfactants to induce protein unfolding or association, which will be detected with small-angle neutron scattering (SANS). Surfactants generally affect protein conformation by disrupting intramolecular or intermolecular amino acid contacts, leading to protein unfolding or the dissociation of protein aggregates, respectively. In the case of photoresponsive surfactants, however, the surfactant-amino acid associations can be switched on or off with simple light illumination. This novel method to photo-control protein conformation will be investigated on several length scales. Protein tertiary and quaternary structure will be determined with SANS through shape-reconstruction computational methods to best fit the scattering data, allowing the in vitro protein structure to be determined. SANS experiments require allocation of competitive beam time from a National Laboratory. This proposal requests funds to allow SANS data to be collected on the bioSANS instrument at Oak Ridge National Laboratory from October 14 through 17 of this year with the participation of a graduate student from the Lee Group. These experiments will allow full characterization of the photo-controlled native-to-intermediate-to-denatured or monomer-to-aggregated transitions in proteins. Broader Impacts. Allowing a graduate student to visit ORNL for three days will provide an invaluable experience. In fact, one of the previous students of the PI now currently works at NIST as a result of similar visits. Chemical Engineering education is faced with a curriculum that has become increasingly disconnected with faculty research. To close this gap, proposals such as this travel award will allow a student to work in the atmosphere in the laboratory with ultimate connectability to features of coursework.