Research Seminar Abstract

Electron microscopy (EM) has yet to be readily applied to biological samples due to a lack of contrast between the various components within a cell. Inorganic nanoparticles (NPs) and stains have been used for biological EM imaging however these approaches generally require several levels of processing making them expensive, tedious, and not wholly applicable.

Metal reducing enzymes (MREs) could provide a biological scaffold to produce ‘Cloneable NPs’, inorganic analogs to fluorescent proteins that can be visualized with electrons and X-rays. Currently, this tag is being realized by utilizing a Glutathione Reductase-like Metalloid Reductase (GRLMR) isolated from an endophyte identified in the Se hyperaccumulator plant Stanleya pinnata. This GRLMR forms naked Se NPs by reducing Se ions to Se(0). GRLMR can be fused to a target protein and when incubated with Se ions and the cofactor NADPH, form and retain Se NPs that can be tracked through EM and elemental analysis. GRLMR provides a springboard to develop a cloneable GFP-like EM tag capable of forming EM tags in situ.