Metalloregulation by MerR and Fur Protein Families

Henry Ford Health + Michigan State University Health Sciences, East Lansing MI

Investigators

Linked publications, trials & patents

Abstract

PROJECT SUMMARY There is a growing need in the biomedical research community to understand the fundamental roles and mechanisms that regulate inorganic chemistry involved in cellular physiology. While many of these metals have been labeled as ‘trace elements,’ from a cellular point of view this is a misnomer: the intracellular concentrations of zinc and iron are routinely maintained at much higher levels (i.e., 0.6 mM). These insights, as well as the emerging literature linking metal physiology to many human disease states, underscore the importance of establishing the fundamental principles, general pathways, and macromolecular mechanisms employed to manage the large numbers of metal ions required for optimal health of a cell. Our approach to the discovery of these novel pathways and principles involves mechanistic and structural characterization of metal receptors that switch on and off genes in a metal dependent manner and that subsequently control the activity of cellular machinery that maintains metal concentrations within narrow ranges. There are three principle thrusts in this proposal: a) determining how zinc regulons are controlled by metalloregulatory switching events through newly discovered protein-RNA interactions; b) establishing mechanisms for how copper, zinc, and mercury sensing metalloregulatory switches control the topology of DNA within an RNA polymerase promoter complex, and then applying these insights to the development of new types of metal ion sensors, and c) developing quantitative metallomic methods that enable researchers across the biomedical research continuum to address the question of how quantitative inorganic phenotypes vary across cells involved in commensal or pathophysiological interactions with the human host. Overall, these aims focus on resolving fundamental questions about the structures, functions, and molecular mechanisms of wide-spread families of metal-sensing metalloregulatory proteins. The proposed experimental approach will employ x-ray crystallography, biophysical methods, single particle cryo-electron microscopy, proteomic, bioanalytical, spectroscopic and bioinformatic methods to understand the pathways that microorganisms use to respond to changing metal ion availability in the growth media, or in the mammalian host. The effects of these biophysical switching mechanisms on intracellular metal physiology will then be examined using novel single cell analytical and imaging methods coupled with traditional batch quantitative measurements with the overarching goal of establishing general principles and mechanisms that control metal ion homeostasis in normal and disease states.