Membrane-active Peptides and Proteins

膜活性肽和蛋白质

• 批准号: 8302356
• 负责人: HUEY W. HUANG
• 金额: $ 31.39万
• 依托单位: RICE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-09-15 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8302356
• 关键词: Adopted; Animals; Apoptosis; Apoptosis Regulator; Apoptotic; Area; Bax protein; Binding; Biological Process; Cancerous; Cell Death; Cell membrane; Cells; Cholesterol; Circular Dichroism; Clinical Trials; Confusion; Cytosol; Dependence; Development; Exhibits; Free Energy; Genes; Goals; Grant; HIV Envelope Protein gp41; Health; Hemagglutinin; Human; Individual; Kinetics; Lipids; Measures; Membrane; Membrane Fusion; Membrane Proteins; Methods; Microbe; Molecular; N-terminal; Neutron Diffraction; Outer Mitochondrial Membrane; Peptides; Phase; Physiological; Play; Positioning Attribute; Principal Investigator; Process; Proteins; Reaction; Research; Respiratory Diaphragm; Roentgen Rays; Role; Simulate; Solutions; Stimulus; Structure; Surface; Suspension substance; Suspensions; System; Testing; Therapeutic; Thick; Vesicle; Viral Fusion Proteins; Work; X ray diffraction analysis; X-Ray Diffraction; antimicrobial; antimicrobial peptide; aqueous; base; cancer cell; cytochrome c; insight; killings; peptide structure; physical state; porin; programs; protein complex; research study; response; theories; unilamellar vesicle

DESCRIPTION (provided by applicant): We propose to study membrane-active proteins and peptides that cause configurational changes in cell membranes, including pore formation and membrane fusion. Pore-forming peptides are animals' (including human's) gene-encoded innate antimicrobials that kill microbes by forming pores in their membranes. Clarification of their molecular mechanisms will facilitate their therapeutic applications. Our studies of this problem have led to a free energy description of peptide-lipid interactions. In specific aim 1 we will extend such studies to the kinetics of pore-formation. Studies of these relatively simple peptides have also contributed to the development of experimental methods that can be used for more complex protein-membrane interactions. Pore-forming proteins include apoptosis regulating proteins, in particular Bax which is soluble in the cytosol under normal conditions, but in the presence of apoptotic stimuli, it translocates to the outer mitochondrial membrane and induces cytochrome c release by forming pores. In specific aim 2, we will analyze the molecular mechanism of pore formation by Bax. The viral fusion protein (hemagglutinin or HIV gp41) inserts the N-terminal fusion peptide into the target membrane to initiate membrane fusion. In specific aim 3 we will study the effect of fusion peptides on the first step of membrane fusion. The molecular mechanisms of membrane-peptide (or -protein) interactions must have a structural basis. Obtaining the structural information for each system is our primary goal. Using oriented membranes containing peptides, we have developed methods for measuring the orientation of the peptides, measuring the membrane thickness as a function of peptide-lipid ratio, detecting and measuring the size of transmembrane pores, and resolving the structures of the peptide-induced pores. We will extend these methods to study pore-forming proteins. The biological functions of membrane-active proteins and peptides will be simulated in kinetic experiments with giant unilamellar vesicles (GUVs). The surface area change and the volume change of the GUV in the kinetic process will be measured. We will then interpret the kinetic results in terms of the structural basis. PHS 398/259 (Rev. 11/07) Page Continuation Format Page PUBLIC HEALTH RELEVANCE: We study an important protein Bax that controls the initiation of programmed cell death called apoptosis. It is known that disruption of the apoptosis pathway would increase the likelihood of the cell becoming cancerous or diseased. Using Bax to induce cell death in cancer cells is in clinical trials.

描述（由申请人提供）：我们建议研究引起细胞膜构型变化的膜活性蛋白和肽，包括孔形成和膜融合。形成孔隙的肽是动物（包括人的）基因编码的先天抗菌药物，通过在其膜上形成毛孔来杀死微生物。澄清其分子机制将有助于其治疗应用。我们对这个问题的研究导致了对肽 - 脂质相互作用的自由能量描述。在特定的目标1中，我们将将此类研究扩展到孔形成的动力学。这些相对简单的肽的研究也有助于开发实验方法，这些方法可用于更复杂的蛋白质 - 膜相互作用。形成孔的蛋白包括调节蛋白质的凋亡，特别是在正常条件下可溶于细胞质的Bax，但是在存在凋亡刺激的情况下，它会易位到线粒体外膜，并通过形成孔通过形成孔诱导细胞色素C释放。在特定的目标2中，我们将通过Bax分析孔形成的分子机制。病毒融合蛋白（血凝素或HIV GP41）将N端融合肽插入靶膜中，以启动膜融合。在特定目标3中，我们将研究融合肽对膜融合的第一步的影响。膜肽（或 - 蛋白质）相互作用的分子机制必须具有结构性基础。获得每个系统的结构信息是我们的主要目标。使用含有肽的定向膜，我们开发了用于测量肽方向的方法，测量膜厚度是肽 - 脂质比的函数，检测和测量跨膜孔的大小，并解决肽诱导的孔的结构。我们将扩展这些方法以研究形成孔的蛋白质。膜活性蛋白和肽的生物学功能将在具有巨大的单层囊泡（GUV）的动力学实验中模拟。将测量表面积的变化和GUV的体积变化。然后，我们将根据结构基础来解释动力学结果。 PHS 398/259（Rev. 11/07）页面延续格式页面公共卫生相关性：我们研究一个重要的蛋白质BAX，控制了称为凋亡的程序性细胞死亡的启动。众所周知，凋亡途径的破坏会增加细胞癌或患病的可能性。在临床试验中，使用BAX在癌细胞中诱导细胞死亡。