CAREER: Biological chemistry of Pb2+ revealed through Pb2+ mediated protein-membrane interactions

职业：通过 Pb2 介导的蛋白质-膜相互作用揭示 Pb2 的生物化学

• 批准号: 1151435
• 负责人: Tatyana Igumenova
• 金额: $ 55万
• 依托单位: Texas A&M Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1151435&HistoricalAwards=false
• 关键词: CAREER; Biological; chemistry; Pb2+; revealed

In this CAREER award, funded by the Chemistry of Life Processes Program in the Chemistry Division, Dr. Tatyana Igumenova describes an integrated research and educational program focused on the biological chemistry of lead (Pb). Despite the well-known effect of Pb(II) exposure on humans, the molecular mechanism of Pb(II) action is poorly understood. Dr. Igumenova PI will use a synergistic structural and functional approach to conduct the first in-depth systematic investigation of Pb(II)-protein interactions. The focus is on a class of peripheral membrane proteins called conserved homology 2, or C2, domains. This protein system enables the PI to tackle an unexplored aspect of Pb(II) action: how it mediates the protein-membrane interactions. The C2 domains selected for these studies are from three parent proteins that are molecular targets of Pb(II). These proteins have different structures and functions, such as signal transduction and membrane trafficking. Dr. Igumenova has assembled a toolkit of biophysical techniques that will enable characterization of Pb(II)-protein interactions in the absence and presence of lipid membranes. The results of the proposed studies will report on how the change in the chemical environment of C2 domains, brought about by Pb(II) binding, affects the downstream reaction, which is the association of C2 with lipid membranes. These results have a potential to transform the conventional view of Pb(II) as a ligand whose action is limited to the formation of high-affinity protein complexes to a ligand that serves as a functional Ca2+ surrogate. The obtained data will enable the PI to identify the predictors of coordination geometries and Pb(II) affinities in membrane-bound and membrane-free C2 domains. This, in turn, will facilitate the identification of other potential Pb(II) targets.Lead (Pb) is a heavy metal that became enriched 1000-fold above its natural level due to human activity. The most prevalent form of lead in the environment, Pb(II), interacts with biological molecules in the cell. Many of these biological molecules are proteins that bind calcium ion under normal conditions. Lead(II) ion successfully competes with calcium ion and binds to these proteins - referred to as molecular targets of Pb(II) - with high affinity. Dr. Igumenova's objective is to determine the features of these proteins that make them bind Pb(II) more tightly than calcium ion and understand the effect of Pb(II) on protein function. One of the broader impacts of the proposed work is entry of students from under-represented groups into graduate programs. Dr. Igumenova will offer ten-week summer research internships, with recruitment facilitated by her activities as a faculty mentor in the NSF-sponsored Louis Stokes Alliance for Minority Participation (LSAMP) and Research Experience for Undergraduates (REU) programs. Professional development and mentoring of the student will be accomplished through research activities, the use of high-end research instrumentation (an 800 MHz NMR instrument), and REU-affiliated programs. As an outreach activity, Dr. Igumenova's laboratory will develop an educational web application (app): "Lead (Pb): the toxic chemistry in action" for the iPhone/iPad/iPod mobile platforms. The objective is to enhance public knowledge of the harmful effects of Pb2+ on the society, from the ancient and modern sources of Pb(II) in the environment to specific Pb(II)-complexed molecular structures generated as a result of Dr. Igumenova's research activities. The benefit for society will be an increase in public awareness to the fact that there is no safe level of Pb exposure.

在这个由化学部生命过程化学项目资助的职业奖中，Tatyana Igumenova 博士描述了一个专注于铅 (Pb) 生物化学的综合研究和教育项目。 尽管 Pb(II) 暴露对人类的影响众所周知，但人们对 Pb(II) 作用的分子机制知之甚少。 Igumenova PI 博士将使用协同结构和功能方法对 Pb(II)-蛋白质相互作用进行首次深入系统研究。 重点是一类称为保守同源 2 或 C2 结构域的外周膜蛋白。 该蛋白质系统使 PI 能够解决 Pb(II) 作用的一个未探索的方面：它如何介导蛋白质-膜相互作用。 这些研究选择的 C2 结构域来自作为 Pb(II) 分子靶标的三种亲本蛋白。 这些蛋白质具有不同的结构和功能，例如信号转导和膜运输。 Igumenova 博士组装了一套生物物理技术工具包，能够在脂质膜不存在和存在的情况下表征 Pb(II)-蛋白质相互作用。 拟议研究的结果将报告由 Pb(II) 结合引起的 C2 结构域化学环境的变化如何影响下游反应，即 C2 与脂质膜的结合。 这些结果有可能改变 Pb(II) 作为配体的传统观点，其作用仅限于与作为功能性 Ca2+ 替代物的配体形成高亲和力蛋白质复合物。 获得的数据将使 PI 能够识别膜结合和无膜 C2 域中配位几何形状和 Pb(II) 亲和力的预测因子。 这反过来将有助于识别其他潜在的 Pb(II) 目标。铅 (Pb) 是一种重金属，由于人类活动，其浓度比其自然水平高出 1000 倍。 环境中最常见的铅形式是 Pb(II)，它与细胞中的生物分子相互作用。 许多这些生物分子是在正常条件下结合钙离子的蛋白质。 铅 (II) 离子成功地与钙离子竞争并以高亲和力与这些蛋白质（称为 Pb(II) 的分子靶标）结合。 Igumenova 博士的目标是确定这些蛋白质的特征，使它们比钙离子更紧密地结合 Pb(II)，并了解 Pb(II) 对蛋白质功能的影响。 拟议工作的更广泛影响之一是让代表性不足群体的学生进入研究生课程。 Igumenova 博士将提供为期十周的夏季研究实习机会，她在 NSF 资助的路易斯斯托克斯少数族裔参与联盟 (LSAMP) 和本科生研究经验 (REU) 项目中担任教师导师，从而促进了招聘工作。 学生的专业发展和指导将通过研究活动、高端研究仪器（800 MHz NMR 仪器）和 REU 附属项目的使用来完成。 作为一项外展活动，Igumenova 博士的实验室将为 iPhone/iPad/iPod 移动平台开发一个教育网络应用程序 (app)：“铅 (Pb)：有毒化学物质的作用”。 目的是提高公众对 Pb2+ 对社会有害影响的认识，从环境中 Pb(II) 的古代和现代来源到 Igumenova 博士研究活动产生的特定 Pb(II) 复合分子结构。 对社会的好处将是提高公众对铅暴露没有安全水平这一事实的认识。