We are just beginning to understand the metabolism of heavy metals and to use their metabolic functions in biotechnology, although heavy metals comprise the major part of the elements in the periodic table.
What mechanisms do bacteria employ for heavy-metal resistance?The research outlines three primary mechanisms: metal ion extrusion, complexation by thiols, and reduction to less toxic states. For instance, cadmium is extruded by RND transporters in gram-negative bacteria, illustrating effective detoxification strategies.How do uptake systems differentiate between structurally similar heavy-metal ions?Bacteria use fast, nonspecific transport systems driven by chemiosmotic gradients, while slower, specific systems utilize ATP hydrolysis. For instance, the CorA system transports both magnesium and manganese ions, displaying the energy trade-offs involved.What is the role of molecular chaperones in nickel metabolism?Chaperones like UreD assist in the post-translational processing of nickel-dependent enzymes such as urease. This functioning involves complex interactions where nickel is incorporated effectively into the enzyme's active site.