Chromium Binding to DNA
Stable Cr-DNA binding is inner-sphere coordination of Cr(III) atoms with DNA groups. This type of binding can also be described as covalent coordinate bonding.
General Characteristics of Chromium-DNA Binding
Human tissues and other biological systems usually encounter Cr in one of its two stable oxidative states, namely, +3 or +6. Although both inorganic Cr(III) and Cr(VI) compounds can cause Cr-DNA binding, the conditions required for this reaction to take place are not identical. At neutral pH, Cr(VI) is completely unreactive toward DNA and requires reductive activation to elicit genetic damage and other forms of biological injury. The reduction process is associated with a transient formation of Cr(V) and Cr(IV) intermediates, organic radicals as by-products, and finally yields thermodynamically...