UC Irvine

Many nucleic acids and proteins require divalent metal ions such as Mg2+ and Ca2+ for folding and function. The lipophilic alignment media frequently used as membrane mimetics also bind these divalent metals. Here we demonstrate the use of 31P NMR spectrum of a metal ion chelator (deoxycytidine diphosphate) to measure the bound [Mg2+] and [Ca2+] in situ for several biological model systems at relatively high divalent ion concentrations (1–10 mM). This method represents a general approach to measuring divalent metal ion binding in NMR samples where the amount and type of metal ion added to the system is known.