On the Mechanisms of IsdG-based Heme Degradation and Inhibition of Heme b Biosynthesis in S. Aureus

有了这个奖项，美国国家科学基金会化学部的生命过程化学计划正在资助北达科他州州立大学的Dr.J. Rodgers的研究，以调查细菌金黄色葡萄球菌如何在细胞中维持适量的血红素。 血红素是一种含铁的分子，使血液呈红色。细菌和地球上几乎所有其他生物都依赖血红素来促进各种细胞功能。尽管绝对需要血红素，但过多的血红素对细胞有毒。因此，为了避免血红素诱导的细胞损伤，生物体细胞中血红素的量被严格调节。罗杰斯研究小组通过应用广泛的化学，生物化学和生物物理实验方法来表征参与调节的蛋白质和酶之间的相互作用，从而深入了解血红素调节的分子基础。 该项目的科学广度为本科生和研究生提供了在血红素生物化学前沿工作的机会，并学习从基因操作到激光光谱学的复杂实验方法。这项研究与北方平原地区最大的媒体公司合作实施的一个外联项目有关。简洁的混合媒体制作解决当前的科学为基础的问题是精心制作的咨询博士罗杰斯教育和娱乐消费者的商业媒体。新媒体的目标是使公民能够更好地剖析科学信息，从错误的信息，因为他们形成自己的观点，以科学为基础的，公共政策issues.The总体目标的项目是表征蛋白质之间的相互作用血红素输入和血红素生物合成系统参与血红素调节S。金黄色。这些蛋白质包括Isd血红素获取途径的末端酶IsdG和IsdI，以及分别催化粪卟啉依赖性（CPD）血红素B生物合成中倒数第二步和最后一步的CpfC和ChdC酶。该项目有两个主要目标。首先，通过热力学、流体力学和动力学方法研究了CPD血红素B生物合成通过IsdG与CpfC和ChdC的相互作用来调节的机制。第二，通过IsdG−O2在冷冻溶液中逐步低温辐射还原产生的中间体的共振拉曼和EPR光谱，探讨了IsdG催化O2依赖性血红素降解的机制。Rodgers博士的研究小组正在研究这些酶和酶催化反应之间的相互作用，这对于理解细胞内血红素B生产和外部血红素B摄取之间的平衡至关重要。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

With this award, the Chemistry of Life Processes Program within the Chemistry Division of the NSF is funding research by Dr. Kenton Rodgers from North Dakota State University to investigate how the bacterium Staphylococcus aureus maintains the appropriate amount of heme in the cell. Heme is the iron-containing molecule that gives blood its red color. Bacteria and nearly all other organisms on our planet rely on heme being available to facilitate a wide variety of cellular functions. Despite the absolute requirement for heme, having too much of it is toxic for cells. Therefore, to avoid heme-induced cellular damage, the amount of heme in an organism's cells is tightly regulated. Dr. Rodgers research group gains insight into the molecular basis of heme regulation by applying a broad array of chemical, biochemical, and biophysical experimental methods to characterize the interplay between the proteins and enzymes involved in the regulation. The scientific breadth of the project affords the undergraduate and graduate students the opportunity to work at the cutting edge of heme biochemistry and to learn sophisticated experimental methods ranging from gene manipulation to LASER spectroscopy. The research is linked to an outreach project implemented in collaboration with the largest media company in the Northern Plains region. Concise mixed-media productions addressing current science-based issues are carefully crafted in consultation with Dr. Rodgers to educate and entertain consumers of commercial media. The goal of the new media is to empower citizens to better dissect scientific information from misinformation as they form their points of view on science-based, public policy issues.The overarching goal of this project is to characterize the interactions between proteins of the heme importing and heme biosynthesis systems involved in heme regulation in S. aureus. These proteins include IsdG and IsdI, the terminal enzymes of the Isd heme acquisition pathway, and the CpfC and ChdC enzymes, that catalyze respectively the penultimate and final steps in coproporphyrin-dependent (CPD) heme B biosynthesis. This project has two principal aims. First, the mechanism by which CPD heme B biosynthesis is regulated through interactions of IsdG with CpfC and ChdC is studied by thermodynamic, hydrodynamic and kinetic methods. Second, the mechanism of IsdG-catalyzed O2-dependent heme degradation is probed by resonance Raman and EPR spectroscopy of intermediates generated through step-wise cryoradiolytic reduction of IsdG−O2 in frozen solution. The interactions between these enzymes and the enzyme-catalyzed reactions being studied by Dr. Rodgers’ group are central to understanding the balance between intracellular heme B production and external heme B uptake.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.