STRUCTURAL STUDIES ON THE ROLE OF ZINC IN BACTERIAL PROLIFERATION

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。最成功的抗生素作为特定细胞过程的基于机制的抑制物，涉及细菌的增殖和毒力。对对单个细菌起防御作用的VanX(万古霉素耐药)和金属内酰胺酶(青霉素耐药)，以及在细胞间细菌通讯(群体猝灭)、控制毒力方面发挥重要作用的AHL-内酰胺酶的机制研究正在进行中。这些体系的共同点是它们依赖于锌(II)的活性，以及它们以高自旋(Hs)Co(II)离子的形式在活性位结合钴的能力。每一项都代表着一个重要的临床目标。我们用X射线吸收光谱(XAS)和多频电子顺磁共振(EPR)研究了上述酶在静止状态下的天然锌和钴取代形式。我们最近开始使用快速冷冻淬火技术来研究催化相关的中间体。更详细的磁共振实验将探索更微妙的结构细节，以建立催化的结构时间表。

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. The most successful antibiotics act as mechanism-based inhibitors of specific cellular processes involved in bacterial proliferation and virulence. Mechanistic investigations of VanX (vancomycin resistance) and the metallo-?-lactamases (penicillin resistance), which play defensive roles for an individual bacterium, and of the AHL-lactonase, which plays a prominent role in intercellular bacterial communication (quorum quenching), controlling virulence, are in process. The common thread to these systems is their dependence on Zn(II) for activty, and their ability to bind cobalt at the active site as the high-spin (hs) Co(II) ion. Each represents an important clinical target. We have used x-ray absorption spectroscopy (XAS) and multi-frequency electron paramagnetic resonance (EPR) to study both the native Zn and Co-substituted forms of the aforementioned enzymes in their resting states. We have recently begun to study catalytically relevant intermediates using rapid-freeze-quench techniques. More detailed magnetic resonance experiments will probe more subtle structural details, in order to establish a structural timeline for catalysis.