Hydration of Guanidinium Ions: An Experimental Search for Like-Charged Ion Pairs

摘要: Guanidinium ions (GdmH+) are reported to form stable complexes (GdmH+/GdmH+) in aqueous solution despite strong repulsive interactions between the like-charged centers. These thought play important roles protein folding, membrane penetration, and formation of dimers. Although GdmH+ weakly hydrated, semiempirical calculations provide evidence that these stabilized by water molecules, which serve structural energetic roles. Specifically, molecules bridge GdmH+/GdmH+ as well involving guanidinium side chains arginine. Potential biological significances have been largely confirmed ab initio molecular dynamics simulations indirect experimental evidence. We report cryo-ion mobility–mass spectrometry results for ion pair confined a nanodroplet—the first direct observation this complex. A second ...