Researcher(s)
- Jasmine Parks, Biochemistry, University of Delaware
- Nicole Nordone, Biological Sciences, University of Delaware
Faculty Mentor(s)
- Clara Chan, Earth Sciences, University of Delaware
Abstract
Iron is one of the most abundant metals within the Earth’s crust, found in both natural and artificial locations. Depending on the location, iron can be beneficial or harmful to its environment. Iron oxidation is a major biogeochemical process that can occur both abiotically, through non-living processes such as oxygen exposure, or through biotic means, catalyzed by microorganisms. Iron-oxidizing organisms have the potential to contribute to bioremediation as they produce insoluble rust particles, which can bind to and immobilize other nutrients or contaminants. Studying iron’s role in different environments can contribute to the understanding of what effect iron has on the microbes that reside there. Leptothrix cholodnii SP-6, a bacterium found in fresh-water environments, has the ability to perform iron oxidation, but does not contain any known iron-oxidizing proteins. We hypothesize that a multicopper oxidase protein, MofA, encoded by the bacteria is capable of oxidizing iron. However, to identify the precise role of MofA, the protein must be purified and localized within the cell. Using column chromatography, MofA was purified using an attached Strep-tag’s binding affinity to a Strep Tactin resin. The purified protein is soaked in either reduced iron or reduced manganese to detect oxidation, confirming its identity as a metal oxidase. Localization of MofA will provide insights as to where the oxidation process occurs on a cellular level. A broad host range plasmid encoding MofA is transferred to L. cholodnii SP-6 via conjugation. The localization of MofA is determined by co-localizing fluorescently labeled MofA with distinct cell components, like the sheath, outer membrane, or cytoplasm. Discovering a novel iron oxidase in L. cholodnii SP-6 will help us better understand the varied abilities of iron-oxidizing microbes in the environment. By fully comprehending the role of microbes in environmental iron oxidation, we can harness their abilities to reduce contaminants and toxins in their environment.