Copper Uptake by Active Cells of Mucor rouxii and Identification of the Copper Binding Proteins

摘要

These results describe the presence of a copper-binding low-molecular-weight component in copper-tolerant Mucor rouxii cells. Most of the total copper bound inside the cells was found associated with this component. The role of this component may be to sequester the copper present inside the cells to allow normal metabolic functions. Our findings support the hypothesis that, as a first defense mechanism to ambient high levels of copper, Mucor rouxii develops molecules with chemical functional groups, that bind the copper ions to the surface of the cell. Such a component could be a copper-binding protein, and copper may be binding to sulfur-containing groups. The transport of this metal to the inside of the cell was demonstrated by the copper content in the cytosol cellular fraction and by the copper interaction with an intracellular protein.