Molecular Imaging of G-Protein-Coupled Receptors for Drug Development

描述（由申请人提供）：G蛋白偶联受体（GPCR）是人体中最重要的蛋白质之一，因为它们是许多信号通路（包括导致疾病的信号通路）的"门户"，并且它们的功能可通过药物干预。通过识别和结合特定的化学物质，GPCR将信号从细胞外传递到细胞内，在细胞内触发一系列生物事件。因此，GPCR是用于结构确定的最丰富的蛋白质类别。它们是最大的一类膜蛋白;约800个GPCR在人类基因组中编码，其中约一半是潜在的药物靶点。然而，它们中只有约60种目前用作小分子药物的受体，其中约25种用于基于天然配体的生物治疗;尽管如此，与GPCR结合的药物占所有治疗药物的约三分之一。预计到2014年，与GPCR相互作用的药物的年度全球市场将达到1180亿美元。超过80种额外的GPCR可能适用于抗体治疗，这是一种受到越来越多关注的新型攻击途径，也是我们将探索的一种途径。从液晶磷脂双层中的大膜蛋白制备用于X射线晶体学和溶液NMR的样品的困难一直是基于结构的药物发现的主要障碍。为了克服这一障碍，我们同时开发了新的方法，固态核磁共振光谱，并应用于膜蛋白的结构测定。我们的主要目标是趋化因子受体CXCR1，在该奖项的前五年中，我们在确定其结构方面取得了实质性进展。我们对白细胞介素-8（IL-8）与CXCR1相互作用的研究为发现可能通过与CXCR1结合来影响炎症、癌症转移和其他疾病的药物提供了一个框架。为了加速与CXCR1和其他GPCR相互作用的药物的设计和发现，我们正在开发一种通用方法，用于确定GPCR在生理条件下天然磷脂环境中的三维结构。这项研究是多学科的，涉及分子生物学，生物化学，结构生物学，核磁共振光谱学和计算。它在培养能够跨越化学和生物界限工作和互动的科学家方面非常有效。我们认识到，它需要最高水平的技术;因此，它是由加州大学圣地亚哥分校（UCSD）和两家生物技术公司（马萨诸塞州安多弗的剑桥同位素实验室（CIL）和加州圣地亚哥的膜受体技术（MRT））组成的生物工程研究伙伴关系。CIL的关键技术是同位素标记的氨基酸和前体的合成，以及独特的同位素标记的细菌生长培养基的制造;他们的工作由Joel布拉德利博士领导。MRT具有表达、纯化和重折叠生物活性GPCR的技术，该技术最初由Hans基弗博士开发，在M-Fold生物技术公司，他仍然参与这项研究。

DESCRIPTION (provided by applicant): G-protein coupled receptors (GPCRs) are among the most important proteins in humans because they are the 'gateway' for many signally pathways, including those that contribute to diseases, and their functions are amenable to intervention by drugs. By recognizing and binding specific chemicals, GPCRs transduce signals from the outside of cell to the inside where they trigger a cascade of biological events. Consequently, GPCRs are the most fecund class of proteins for structure determination. They are the largest class of membrane proteins; ~800 GPCRs are encoded in the human genome, about half of which are potential drug targets. However, only ~60 of them are currently used as receptors for small molecule drugs and ~25 of them for bio- therapeutics based on the natural ligand; nonetheless, drugs that bind to GPCRs account for about one-third of all therapeutic drugs. The annual worldwide market for drugs that interact with GPCRs is predicted to be $118 Billion by 2014. More than 80 additional GPCRs are potentially amenable to antibody therapeutics, a novel avenue of attack that is receiving increasing attention, and one that we will explore. The difficulty in preparing samples for X-ray crystallography and Solution NMR from large membrane proteins in liquid crystalline phospholipid bilayers has been the principal roadblock to structure-based drug discovery. In order to overcome this roadblock we have simultaneously developed new methods for solid-state NMR spectroscopy and applied to structure determination of membrane proteins. Our principal target is the chemokine receptor CXCR1, and we have made substantial progress towards determining its structure during the first five years of this award. Our studies of interleukin-8 (IL-8) interacting with CXCR1 provide a framework for discovery of drugs that may affect inflammation, cancer metastasis, and other diseases by binding to CXCR1. In order to accelerate the design and discovery of drugs that interact with CXCR1 and other GPCRs, we are developing a general method for determining the three-dimensional structures of GPCRs in their native phospholipid environment under physiological conditions. This research is multidisciplinary, involving molecular biology, biochemistry, structural biology, NMR spectroscopy, and computation. It is highly effective at training scientists who can work and interact across chemical and biological boundaries. We recognize that it requires the highest levels of technology available; as a result, it is organized as a Bioengineering Research Partnership among the University of California, San Diego (UCSD) and two biotechnology companies (Cambridge Isotope Laboratories (CIL), Andover, Massachusetts and Membrane Receptor Technologies (MRT), San Diego, California. CIL's key technology is the synthesis of isotopically labeled amino acids and precursors, and the manufacture of unique isotopically labeled bacterial growth media; their effort is led by Joel Bradley, Ph.D. MRT has the technology for the expression, purification, and refolding of biologically active GPCRs developed originally by Hans Kiefer, Ph.D., at M-Fold Biotech and he remains involved in the research.