... protein ratio,the resonances of Arg20, Asp22 and Asp23 disap-peared, and the resonance of Leu21 shifted. At a 2 : 1ratio, the resonances of residues 19 and 44 also disap-peared, whereas those of ... chains of Asp76 (1.9 A ˚) and Asp27(2.4 A ˚) of a symmetry-related molecule and four watermolecules (1.9 A ˚, 2.1 A ˚, 3.1 A ˚ and 3.0 A ˚) coordinatethe cation with an approximate octahedral ... cause paramagnetic shifts or influence thetransversal relaxation. Conversely, two equivalents of the ion cause the shift and disappearance of severalsignals, without the concomitant appearance...