Thus, RNA is exposed to large amounts of amino acid-chelated magnesium in cells.Įffects of free amino acids on RNA folding and catalysis in vitro are generally considered to be inhibitory. Recent metabolome analyses report greater than one hundred millimolar of amino acids, which account for ~50% of all metabolites in E. However, free concentrations of magnesium, meaning fully hydrated by water at the inner-coordination sites on Mg 2+, are only ~0.5–1 mM in eukaryotic cells and ~1.5–3 mM in bacterial cells since most magnesium in the cytoplasm interacts with metabolites, proteins, and nucleic acids 6, 9. In a recent metalome studies in Escherichia coli, total concentrations of potassium and magnesium ions were found to be relatively high, at 140–160 mM and 54 mM, respectively (Supplementary Fig. ~1 M Na + and ~10 mM Mg 2+), the folding mechanisms of various RNA species have been studied in cellular mimicked conditions induced by cosolutes, and it is widely accepted that such crowding conditions increase ribozyme folding and activity 2, 3, 4, 5, 6, 7, 8, 9. In addition to primarily “classical standard in vitro conditions”, which are high monovalent and divalent ion concentrations (e.g. Folding mechanisms, therefore, play significant roles in RNA function and related biological phenomena. RNA molecules fold into unique three dimensional structures, which allow them to function as catalysts that perform biochemical reactions and regulators that control protein expression 1. Overall, these results indicate that the states of Mg 2+ should not be limited to free and bound only, as weakly bound Mg 2+ strongly promotes RNA function under cellular conditions. Other metabolites that weakly chelate magnesium offer similar beneficial effects, which implies chelated magnesium may enhance RNA function in the cell in the same way.

Furthermore, aaCM enhance self-cleavage of several different ribozymes, up to 100,000-fold at Mg 2+ free of just 0.5 mM, indirectly through RNA compaction. Amino acid-chelated Mg 2+ (aaCM) of ~15 mM dramatically increases RNA folding and prevents RNA degradation. To uncover cellular behavior of RNA, we devised cytoplasm mimic systems that include biological concentrations of amino acids, which weakly chelate Mg 2+.

Most RNA folding studies have been performed under non-physiological conditions of high concentrations (≥10 mM) of Mg 2+ free, while actual cellular concentrations of Mg 2+ free are only ~1 mM in a background of greater than 50 mM Mg 2+ total.

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