Experimental and Modeling Study of the Optical Properties and Phase Behavior of Heat and Cold Tolerant Eye Lens Crystallins

该项目的目的是了解和模拟结构蛋白的特性，以适应抵抗极端环境。实验和理论技术的结合将用于探索由来自不同生物体的晶状体蛋白质保持透明度的分子机制。科学目标是了解大自然是如何产生透明、耐用的生物材料的，就像构成晶状体的蛋白质一样。生活在非常热、寒冷或紫外线饱和环境中的动物的晶体可以为制造能够承受恶劣条件的坚固、可生物降解的材料提供指导。从该项目中获得的知识将指导柔性材料的设计，这些材料具有潜在的应用于新的仿生透镜设计，在医学和分析化学背景下，柔性微透镜和抗紫外线损伤的自修复材料。在未来，它可以促进生物无机水凝胶支架、可控无膜生物反应器和海洋安全、可生物降解的防晒霜的发展。该教育计划包括培养博士和本科生。这些学生不仅要接受完成研究所需的特定技能的培训，还要接受批判性思维、科学交流和跨学科解决问题的培训。另一个重要的组成部分是向6-12年级的初中生和高中生伸出援手。拓展计划的目标是提高中学生对科学作为职业的兴趣。这些学生中的许多人来自经济背景不佳的家庭，他们来到UCI参加校园之旅，了解本科生的生活，在研究人员的实验室进行动手活动，并与本科生研究人员互动。该项目的目的是了解适应极端环境的蛋白质的溶解度和稳定性。在非常不同的环境中发挥相同功能作用的高度稳定结构蛋白的实验和建模研究将提供对稳定性和溶解度的序列决定因素的见解。结构蛋白和折光蛋白的选择是为了避免来自序列特征的干扰，这些序列特征是保守的，以维持热稳定性酶的化学活性。该项目的科学目标是了解大自然是如何产生透明、耐用的生物材料的，就像构成晶状体的蛋白质一样。尽管这些蛋白质的分子细节在不同的生物体中有所不同，但它们的高稳定性和对极端温度的抵抗力在功能上是相似的。为此选择的特定蛋白质是适应极端环境的晶状体结晶蛋白。箱形水母（Tripedalia cystophora）的J2结晶蛋白和被囊动物（Ciona intestalis）的βγ-结晶蛋白在热变性方面非常稳定。这些蛋白质不是同源的，但有一个共同的功能；我们试图了解热稳定性的顺序和结构决定因素。另一方面，南极犬牙鱼（Dissostichus mawsoni）的γS-和γ m结晶蛋白在-2℃或更低的温度下抵抗冷白内障，远低于哺乳动物晶状体发生冷白内障的温度。这些蛋白质以一种复杂的混合物存在，在鱼的晶状体中有13个类似物。一个目标是了解和控制涉及冷白内障的液-液相分离。昼行性壁虎Lygodactylus picturatus体内的晶状体蛋白结合了一种经过修饰的视色素视黄醇，以保护其视网膜免受明亮阳光下紫外线的伤害。核磁共振、光谱学、光散射和定向诱变实验将与分子动力学和蒙特卡罗模拟相结合，阐明赋予这些蛋白质高稳定性和抗极端条件的重要结构因素和分子间相互作用，指导未来仿生材料的设计。了解不同晶状体蛋白的共同结构因素将有助于指导未来抗温度和抗紫外线仿生材料的设计。此外，预测和控制蛋白质混合物中液-液相分离的形成和解离的能力将有助于调节蛋白质聚集和生化活性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical summaryThe objective of this project is to understand and mimic the properties of structural proteins that are adapted to resist extreme environments. A combination of experimental and theoretical techniques will be used to explore the molecular mechanisms by which eye lens proteins from different organisms maintain transparency. The scientific goal is to understand how nature produces transparent, durable biomaterials, as exemplified by the proteins making up the eye lens. The lenses of animals that live in very hot, cold, or UV light-saturated environments can provide a guide to making robust, biodegradable materials that withstand harsh conditions. The knowledge gained from this project will guide the design of flexible materials with potential applications to new biomimetic lens designs, in both the medical and analytical chemistry contexts, flexible microlenses, and self-healing materials that resist UV-light damage. In the future, it could enable the development of bioinorganic hydrogel scaffolds, controllable membraneless bioreactors, and ocean-safe, biodegradable sunscreen. The educational plan includes training of students at the Ph.D. and undergraduate levels. These students will be trained not only in the specific skills needed to complete the research, but also in critical thinking, scientific communication, and problem solving across disciplinary boundaries. Another important component is outreach to middle school and high school students in grades 6-12. The goal of the outreach program is to increase interest in science as a career among middle school students. The students, many of whom are from disadvantaged economic backgrounds, visit UCI to participate in a campus tour where they learn about undergraduate life, perform hands-on activities in the investigators’ laboratories, and interact with undergraduate researchers.  Technical summaryThe objective of this project is to understand the solubility and stability of proteins that are adapted to resist extreme environments. Experimental and modeling studies of highly stable structural proteins that play the same functional role in very different environments will provide insight into sequence determinants of stability and solubility. Structural and refractive proteins are chosen specifically to avoid interference from sequence features that are conserved to maintain chemical activity in thermostable enzymes. The scientific goal of this project is to understand how nature produces transparent, durable biomaterials, as exemplified by the proteins making up the eye lens. Although the molecular details of these proteins vary among different organisms, they are functionally similar in their high stability and resistance to temperature extremes. The specific proteins chosen for this effort are eye lens crystallins that are adapted to extreme environments. The J2 crystallin from the box jellyfish Tripedalia cystophora and the βγ-crystallin from the tunicate Ciona intestinalis are extremely stable with respect to heat denaturation. These proteins are not homologous but share a common function; we seek to understand the sequence and structural determinants of thermal stability. On the other hand, the γS- and γM-crystallins from the Antarctic toothfish (Dissostichus mawsoni) resist cold cataract at -2 C or lower, far below the temperature at which mammalian lenses undergo cold cataract. These proteins exist in a complex mixture, with 13 paralogs in the fish lens. One goal is to understand and control the liquid-liquid phase separation involved in cold cataract. The iota-crystallin from the diurnal gecko Lygodactylus picturatus binds a modified form of the visual pigment retinol to protect its retinae from UV light damage in bright sunlight. NMR and optical spectroscopy, light scattering, and directed mutagenesis experiments will be coupled with molecular dynamics and Monte Carlo simulations to elucidate the important structural factors and intermolecular interactions that confer high stability and resistance to extreme conditions on these proteins, guiding the future design of biomimetic materials. Understanding the structural factors diverse lens proteins have in common will help guide the design of future temperature- and UV-resistant biomimetic materials. Furthermore, the ability to predict and control the formation and dissociation of liquid-liquid phase separation in protein mixtures will be useful for modulating protein aggregation and biochemical activity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.