CRYSTAL STRUCTURES OF POLYKETIDE SYNTHASES: STRUCTURE-BASED DRUG DESIGN OF NOVEL

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 聚酮是一类结构多样的天然产物，具有广泛的药理活性，包括抗癌、抗生素、抗病毒和免疫抑制特性，2005年占全球医药市场的300亿美元。它们在自然界中是由有限的简单羧酸通过称为聚酮合成酶(PKS)的多功能蛋白质合成的。I型PKSS是当前研究的目标，具有模块化的体系结构。确定PKSS的晶体结构将极大地有助于系统地探索体系的结构特征，并产生对关键特征的关键见解，如结构域边界和底物选择性。这将反过来允许通过蛋白质工程或底物工程对PKS进行修饰，以生产下一代“非天然”聚酮产品。最近，我们已经解决了6-脱氧赤藓内酯B合成酶(6-Debs)194 kDa的同源二聚体片段(6-Debs)的晶体结构，以及分别来自6-Debs和印尼霉素聚酮合成酶的两个硫代酯酶的晶体结构，以及R1128聚酮合成酶的启动酮合成酶(ZHH)的晶体结构。鉴于多酮在合成有机化学和药物发现中的重要性，解决这些蛋白质的晶体结构只是利用PKSS进行基于结构的药物设计的开始，最终目的是获得各种合成类似物，作为大环药物先导物库。随着我们对这些蛋白质结构的研究的继续，我们将利用SSRL的波束时间来解析酮合成酶(KS)-酰基载体蛋白(ACP)蛋白质片段的晶体结构，该蛋白质片段将通过模块3DeB中的两个单独结构域的不可逆共价交联而获得。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Polyketides are a structurally diverse class of natural products that exhibit a diverse range of pharmacologically relevant activities including anti-cancer, antibiotic, anti-virus, and immunosuppressive properties, accounting for $ 30 billion of the worldwide pharmaceutical market in 2005. They are synthesized in nature from a limited repertoire of simple carboxylic acids by multifunctional proteins called polyketide synthases (PKSs). Type I PKSs, the target of the current study have a modular architecture. Determination of crystal structures of PKSs will greatly aid in systematically exploring the architectural features of the system and yield key insights into critical features such as domain boundary and substrate selectivity. This would in turn allow modification of PKSs by protein-engineering or substrate-engineering to produce the next generation of "unnatural" polyketide products. In the recent past we have solved the crystal structure of a 194 kDa homodimeric fragment of the 6-deoxyerythronolide B synthase(6-DEBS), in addition to the crystal structures of two thioesterases from 6-DEBS and picromycin polyketide synthase respectively and the crystal structure of priming ketosynthase (ZhuH) from R1128 polyketide synthase solved earlier utilizing the beamtime at SSRL. Given the importance of the polyketides in synthetic organic chemistry and drug discovery, solving the crystal structures of these proteins is only the beginning of structure-based drug design utilizing PKSs with the ultimate goal of accessing a variety of synthetic analogs which would serve as a library of macrocycle drug leads. In continuation with our studies on the structure of these proteins, beamtime at SSRL will be utilized to solve the crystal structures of a ketosynthase (KS)-acyl carrier protein (ACP) protein fragment which will be obtained via irreversible covalent cross-linking of the 2 individual domains from module 3 DEBS.