STUDIES OF THE DIDOMAIN OF A POLYKETIDE SYNTHASE MODULE

聚酮合成酶模块双结构域的研究

• 批准号: 7597968
• 负责人: IRIMPAN I MATHEWS
• 金额: $ 0.16万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-01 至 2008-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7597968
• 关键词: 4' -phosphopantetheine; Active Sites; Acyl Carrier Protein; Agrochemicals; Anabolism; Antibiotics; Antifungal Agents; Antiparasitic Agents; Area; Bacteria; Biochemical; Biological Factors; Carboxylic Acids; Complex; Computer Retrieval of Information on Scientific Projects Database; Data Set; Enzymatic Biochemistry; Enzymes; Erythromycin; Exhibits; Family; Funding; Grant; Immunosuppressive Agents; Institution; Knowledge; Location; Malignant Neoplasms; Maps; Phase; Positioning Attribute; Property; Radiation; Research; Research Personnel; Resources; Robot; Screening procedure; Selenium; Sirolimus; Site; Source; Structure; Techniques; Tertiary Protein Structure; Type I Polyketide Synthase; United States National Institutes of Health; Upper arm; antimicrobial; electron density; interest; picromycin; polyketide synthase

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 group of compounds exhibiting remarkable diversity in terms of their structure and function. Polyketides natural products are known to possess a wealth of pharmacologically important activities, including antimicrobial, antifungal, antiparasitic, antitumor, and agrochemical properties. Erythromycin (antibiotic), epothilone (anti cancer), pikromycin (antibiotic), and rapamycin (immunosuppressant) are just few examples of the polyketide natural product family. Remarkably, these complex structures are synthesized in bacteria from simple carboxylic acids by multifunctional enzyme assemblies called modular, or type I, polyketide synthases (PKSs). While polyketide biosynthesis has been an active area of research, many structural and fundamental aspects of modular PKS enzymology still remain obscure. We have crystallized a didomain from the modular PKS. These crystals generally showed poor diffraction and radiation damage. After screening hundreds of crystals using the SSRL robot, we collected three MAD data sets. This enabled the location of 90 selenium sites and a traceable electron density map. This is the first structure of a didomain from PKS and this structure answered several interesting biochemical questions. The didomain complex has 582 kDa per asymmetric unit. To our knowledge this is the largest structure solved to date using MAD phasing technique. The crystal structure reveals that the active site Cys199 residue of the KS domain is more than 80 ¿ away from the active site Ser642 residue of the AT domain. This distance is too large to be covered simply by alternative positioning of a fixed, fully extended phosphopantetheine arm of the acyl carrier protein (ACP) domain from module 5. Thus, substantial domain reorganization appears necessary for the ACP to interact successively with both the AT and the KS domains of this prototypical polyketide synthase module.

该副本是使用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这是调查员的机构。 聚酮化合物是一组在其结构和功能方面表现出显着多样性的化合物。众所周知，Polyketides天然产物具有大量重要的药物活性，包括抗菌，抗真菌，抗寄生虫，抗肿瘤和农业化学特性。红霉素（抗生素），雌激素（抗癌），pikromycin（抗生素）和雷帕霉素（免疫抑制剂）只是Polyketide Natural Propers系列的几个例子。值得注意的是，这些复杂的结构是通过称为模块化或I型Polyketide合酶（PKSS）的多功能酶组件在细菌中合成的。虽然Polyketide的生物合成一直是研究的活跃领域，但模块化PKS酶学的许多结构和基本方面仍然晦涩难懂。我们已经从模块化PK中结晶了一个didomain。这些晶体通常显示出较差的衍射和辐射损伤。使用SSRL机器人筛选数百个晶体后，我们收集了三个MAD数据集。这使90个硒位点和可追溯的电子密度图的位置。这是与PKS不同的第一个结构，该结构回答了几个有趣的生化问题。 Didomain复合物每个不对称单元具有582 kDa。据我们所知，这是迄今为止使用MAD相位技术解决的最大结构。晶体结构表明，KS结构域的活性位点Cys199居住地距离AT域的活性位点SER642居住地超过80。该距离太大，无法简单地通过模块5的酰基载体蛋白（ACP）结构域的固定，完全扩展的磷酸乙氨酸臂的替代定位。