STRUCTURE-FUNCTION STUDIES ON ENZYMES INVOLVED IN THE LYSINE BIOSYNTHETIC PATHWA

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 赖氨酸的细菌生物合成形成了用于设计新的抗微生物剂的有吸引力的靶标，因为该途径对于细菌是必不可少的并且在人类中不存在。我们已经对细菌病原体和植物中赖氨酸生物合成所涉及的酶靶标进行了结构研究。其中两种酶，即流感嗜血杆菌的二氨基庚二酸差向异构酶和拟南芥的LL-二氨基庚二酸氨基转移酶的晶体结构最近已被确定。这些酶与抑制剂的复合物和突变形式的结构工作正在继续进行，以了解设计有效抑制剂的催化机制的细节。最近，我们从拟南芥中获得了二氨基庚二酸差向异构酶的晶体。此外，目前正在对来自人类病原体衣原体的二氨基庚二酸氨基转移酶进行结晶试验。我们正在进行合作，对80，000种化合物进行高通量筛选，以便在我们针对衣原体感染的药物设计工作中为晶体学分析找到潜在的抑制剂线索。其他正在进行结晶试验的靶点包括来自结核分枝杆菌的二氨基庚二酸脱琥珀酸酶。为了获得尽可能好的衍射数据分辨率和质量，以及使用MAD/SAD方法进行从头结构求解，我们需要使用同步加速器光束线进行大分子晶体学研究。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Bacterial biosynthesis of lysine forms an attractive target for the design of new antimicrobial agents because this pathway is indispensable for bacteria and is absent in humans. We have undertaken structural investigations on enzyme targets involved in the biosynthesis of lysine from bacterial pathogens and plants. Crystal structures of two of these enzymes, namely, diaminopimelate epimerase from Haemophilus influenzae and LL-diaminopimelate aminotransferase from Arabidopsis thaliana have been determined recently. Structural work is continuing on these enzymes in complex with inhibitors and of mutant forms to understand details of the catalytic mechanism for the design of effective inhibitors. Recently, we have obtained crystals of the diaminopimelate epimerase from Arabidopsis. Also, crystallization trials are currently underway on the diaminopimelate aminotransferase from the human pathogen, Chlamydia. We have an ongoing collaboration for high-throughput screening of 80,000 chemical compounds in order to find potential inhibitor leads for crystallographic analysis in our drug design efforts against Chlamydial infections. Other targets undergoing crystallization trials include diaminopimelate desuccinylase from the tuberculosis causing mycobacteria. In order to achieve the best possible resolution and quality of diffraction data, as well as for de novo structure solution using MAD/SAD methods, we require access to the synchrotron beamlines for macromolecular crystallography.