NMR STUDIES OF CHLOROPHYLL A IN PHOTOSYNTHETIC MEMBRANE

光合膜中叶绿素A的核磁共振研究

• 批准号: 3777844
• 负责人: PHOEBE K DEA
• 金额: --
• 依托单位: CALIFORNIA STATE UNIVERSITY LOS ANGELES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3777844
• 关键词: calorimetry; chemical chain length; chlorophyll; diacylglycerols; galactolipids; lipid bilayer membrane; membrane model; nuclear magnetic resonance spectroscopy; phosphatidylcholines; phospholipids; photosynthesis; porphyrin structure

Photosynthesis is one of the basic processes in nature in which the energy of sunlight is efficiently converted into chemical energy, a reaction as yet difficult to mimic in vitro. While the function of chlorophylls in the photosynthetic process is reasonably well defined, the structural organization of the light-harvesting chlorophylls in the thylakoid is a subject of considerable current interest. The proposed research extends work carried out during the previous funding period on the organization of chlorophyll alpha in dimyristoyllecithin bilayer membranes. In this project, high field deuterium (2H) NMR spectroscopy will be used as the principal technique to study the specific interactions between chlorophyll and the thylakoid lipids. 2H-NMR relaxation measurements provide an ideal means of observing slow motions in lipid bilayers. 2H is a quadrupolar nucleus, and the quadrupolar interaction dominates other spin interactions in the 2H NMR relaxation expression. In addition, the lipid hydrocarbon chains may be deuterated at a single position allowing selective observation of a particular region of the bilayer. We will use the angular dependence of the spin-spin relaxation rate (T2-1) and the dependence of T2-1 on the order parameter to characterize the nature of slow motions and to determine the contribution of director fluctuations to T2-1 in the galactolipid membrane and in the presence of chlorophyll alpha. Ancillary techniques will include optical spectroscopy and chromatography as requisite for the isolation, purification and purity determination of chlorophylls and lipids, and will include differential scanning calorimetry as an adjunct to the NMR technique. This research project should shield useful information on the phase behavior, interaction and dynamics of chlorophyll alpha in lipid membranes. The project will also provide student participants with research exposure and training in biomedical research, thereby motivating students to pursue a career in biomedical research through close counseling and supervision, as well as through group dynamics of the research project team.

光合作用是自然界的基本过程之一，其中能量 阳光有效地转化为化学能，反应如下 但很难在体外模拟。 虽然叶绿素的功能 光合作用过程有相当明确的定义，结构 类囊体中捕光叶绿素的组织是 当前引起人们极大兴趣的主题。 拟议的研究扩展了先前资助期间开展的工作 二肉豆蔻酰卵磷脂中叶绿素α的组织周期 双层膜。 在这个项目中，高场氘 (2H) NMR 光谱学将作为主要技术来研究特定的 叶绿素和类囊体脂质之间的相互作用。 2H-核磁共振 松弛测量提供了观察慢运动的理想方法 脂质双层。 2H是四极核，四极 2H NMR 弛豫中相互作用主导其他自旋相互作用 表达。 此外，脂质烃链可以在以下温度下氘化： 单个位置允许选择性观察特定区域 双层。 我们将利用自旋-自旋的角度依赖性 弛豫率 (T2-1) 以及 T2-1 对有序参数的依赖性 描述慢动作的性质并确定其贡献 半乳糖脂膜和 T2-1 的导向波动 叶绿素α的存在。 辅助技术将包括光学 光谱学和色谱法作为分离所必需的， 叶绿素和脂质的纯化和纯度测定，并将 包括差示扫描量热法作为 NMR 的辅助手段 技术。 该研究项目应屏蔽有关该阶段的有用信息 叶绿素α在脂质膜中的行为、相互作用和动力学。 该项目还将为学生参与者提供研究机会 和生物医学研究培训，从而激励学生追求 通过密切的咨询和监督从事生物医学研究的职业， 以及通过研究项目团队的群体动力。