Membrane Protein Stability

膜蛋白稳定性

基本信息

批准号：
8786084
负责人：
Karen G. Fleming
金额：
$ 33.96万
依托单位：
JOHNS HOPKINS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-06-01 至 2017-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8786084
关键词：
Achievement Address Basic Science Binding Biological Biophysical Process Biophysics Burial Cell physiology Charge Chemicals Computer Simulation Coupling Data Dependence Disease Engineering Equilibrium Escherichia coli Free Energy Goals Grant Head Health Human body Hydrophobicity Kinetics Knowledge Lead Lipids Location Marketing Measurement Measures Membrane Membrane Proteins Modeling Molecular Molecular Conformation Mutation Organic solvent product Pharmaceutical Preparations Play Positioning Attribute Process Proteins Regulation Research Role Scaffolding Protein Side Site Sorting - Cell Movement Specific qualifier value Structural Protein Structure Testing Therapeutic Thermodynamics Water Work aspartylglutamate base biophysical analysis biophysical techniques combat design driving force insight microbial microorganism mutant novel protein folding protein misfolding protein structure research study scaffold

项目摘要

DESCRIPTION (provided by applicant): Membrane proteins play essential roles in many cellular processes. The overall goal of the proposed research is to understand the physical basis of the protein folding process and the biophysical basis of membrane protein structures. At present, neither of these is well understood for membrane proteins. Thermodynamically, our work addresses the critical role that hydrophobicity plays in membrane protein folds. In the previous granting period, we developed a novel hydrophobicity scale that measures side-chain transfer free energies from water to the membrane center using a real bilayer and a real, folded membrane protein. Based on this achievement, we now propose to test the generality of this scale (1) By measuring side-chain transfer free energies using distinct membrane protein scaffolds; (2) By determining how extent-of-burial in the bilayer modulates water to bilayer transfer free energies; and (3) By engineering of our protein scaffold for measurements as a function of pH to address how the energetic consequences of ionizable group mutations vary with charge state. Kinetically, we discovered in the previous grant period that E. coli lipid head groups may act as energetic potentials that sort membrane proteins away from the wrong (inner) membranes and towards the correct (outer) membrane locations. We propose in a fourth aim to dissect the biophysical basis for this sorting by determining the kinetic lifetimes and conformations and activation energies to folding induced by E. coli-containing lipid head groups.

描述（由申请人提供）：膜蛋白在许多细胞过程中发挥重要作用。该研究的总体目标是了解蛋白质折叠过程的物理基础和膜蛋白结构的生物物理基础。目前，对于膜蛋白，这些都还没有被很好地理解。从热力学角度来看，我们的工作解决了疏水性在膜蛋白折叠中发挥的关键作用。在之前的资助期间，我们开发了一种新型疏水性量表，使用真正的双层和真正的折叠膜蛋白来测量从水到膜中心的侧链转移自由能。基于这一成果，我们现在建议测试该尺度的普遍性（1）通过使用不同的膜蛋白支架测量侧链转移自由能； (2) 通过确定双层中的埋藏程度如何调节水到双层的自由能传递； (3) 通过设计我们的蛋白质支架来测量 pH 值的函数，以解决可电离基团突变的能量后果如何随电荷状态变化。从动力学上来说，我们在之前的资助期内发现大肠杆菌脂质头群体可能充当能量势，将膜蛋白从错误的（内）膜分类到正确的（外）膜位置。我们的第四个目标是通过确定含有大肠杆菌的脂质头基诱导的折叠的动力学寿命、构象和活化能来剖析这种分类的生物物理基础。