Structural investigations of native and mutant human green cone pigment

天然和突变人类绿锥体色素的结构研究

基本信息

批准号：
8805694
负责人：
Nathan Alexander
金额：
$ 9.41万
依托单位：
CASE WESTERN RESERVE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-12-02 至 2016-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8805694
关键词：
11 cis Retinal Affect Binding Biological Process Chemicals Color Color Visions Complex Cone Crystallization Data Electrostatics Endoplasmic Reticulum Eye G-Protein-Coupled Receptors Geometry High Performance Computing Human Hybrids Investigation Ions Knowledge Lead Light Link Mechanics Methods Methyl Green Modeling Molecular Molecular Conformation Mutate Mutation Ophthalmology Opsin Organized by Structure Protein Outcome Pharmacology Photons Pigments Property Proteins Research Resolution Retina Retinal Retinal Pigments Rhodopsin Schiff Bases Signal Transduction Structural Models Structure System Therapeutic Transducin Universities Vision Vision research Visual Visual Perception Water X ray diffraction analysis X-Ray Crystallography X-Ray Diffraction base chemical property chromophore computer studies cost electronic structure insight laboratory facility light intensity loss of function molecular mechanics mutant prevent programs protein folding protein misfolding protein structure prediction public health relevance quantum research study theories therapeutic development three dimensional structure tool

项目摘要

DESCRIPTION (provided by applicant): The green cone pigment absorbs light maximally at a wavelength of 530 nm. Three cone pigments in the retina with distinct light absorbance spectra make trichromatic color vision possible. Despite having unique absorbance spectra, these three pigments utilize the same chemical chromophore, 11-cis-retinal. Absorbance of light isomerizes 11-cis-retinal to all-trans-retinal and activates the pigment protein to propagate the signal down the visual cascade. Understanding how green cone pigment specifically affects the chromophore to maximally absorb 530 nm wavelength light will reveal a basic mechanism of visual function. This will be accomplished by determining a high resolution protein structure by X-ray crystallography together with detailed quantum chemical calculations. The structural conformation and chemical interactions revealed by combining experiments with theory will demonstrate the influence of the protein on the chromophore. With these new insights, two mutations will be introduced and characterized for their influence on the structure of the green cone pigment. The W177R green pigment mutation prevents the protein from folding properly, causing the protein to be retained in the endoplasmic reticulum. This gross structural perturbation will be investigated using the Rosetta protein structure prediction suite. Energetic calculations will reveal key interactions lacking in the W177R mutation that are required for proper protein folding. The A180S mutation does not alter folding of the green cone pigment. To understand the mechanism by which the A180S mutation alters absorbance, we will determine the structure of the mutant pigment experimentally by X-ray crystallography. As with native green cone pigment, a combination of experiment and theory will be used to understand the structural and chemical effects of the A180S mutation. Very few pathogenic mutations have been characterized for cone pigments, a critical step in developing potential therapeutics for deficiencies in human color vision.

描述（由申请人提供）：绿色锥色素在530 nm的波长下最大程度地吸收光。视网膜中具有独特光吸光度光谱的三种锥体色素使三色色彩视觉成为可能。尽管具有独特的吸光度光谱，但这三种颜料还是利用了相同的化学发色团（11- cis-视视网膜）。光的吸光度异构使11- cis视视网膜视网膜视网膜视网膜视网膜注视，并激活色素蛋白以使信号传播视觉级联反应。了解绿色锥色素如何特异性影响发色团以最大吸收530 nm波长光将揭示视觉功能的基本机制。这将通过通过X射线晶体学以及详细的量子化学计算来确定高分辨率蛋白质结构来实现。通过将实验与理论相结合的结构构象和化学相互作用将证明蛋白质对发色团的影响。有了这些新见解，将引入和特征两个突变，以其对绿色锥色颜料结构的影响。 W177R绿色颜料突变可防止蛋白质正确折叠，从而导致蛋白质保留在内质网中。这种总体结构扰动将使用Rosetta蛋白结构预测套件进行研究。能量计算将揭示W177R突变缺乏关键的相互作用，这是正确蛋白质折叠所需的。 A180S突变不会改变绿锥色素的折叠。为了了解A180S突变改变吸光度的机制，我们将通过X射线晶体学实验确定突变色素的结构。与天然绿色锥色素一样，实验和理论的结合将用于理解A180S突变的结构和化学作用。很少有病原突变的特征在于锥体色素，这是为人类色觉缺陷开发潜在的治疗剂的关键步骤。