Solution folding of a protein removes major sections of it from their aqueous environment. Complete removal, by forming water-free gaseous protein ions with electrospray ionization/mass spectrometry, profoundly changes the conformation of cytochrome c. Of these ions' exchangeable hydrogen atoms, gaseous D2O replaces 30% to 70% in distinct values indicative of at least six conformational states. Although this is increased to >95% by colliding ions with D2O, colliding instead with N2 and subsequent D2O exposure gives the same H/D exchange values, although in different proportions; on solvent removal, denatured ions spontaneously refold. Deuterated State I, II, and V ions of a range of charge values up to 17+ when charge stripped to 9+ ions do not fold appreciably, even though their cross section decreases by 20%, confirming that each has a characteristic conformational structure insensitive to electrostatic repulsion; the charge solvation of an added protonated side chain also protects additional exchangeab...