Figure 3.

Spin-lattice (T₁) ¹H relaxation times for the various residues in collagen, powdered cortical bone, and demineralized bone in the absence and in the presence of Cu–EDTA (30 mM). The T₁ values were determined from ¹H-spin-inversion recovery experiments detected in ¹³C Ramp-CP MAS, and the reported errors were estimated from the best-fitting of experimental data. All measurements were performed on a 900 MHz Bruker AVANCE solid-state NMR spectrometer. Other experimental and data processing details are mentioned in Figure 1 caption. A, alanine; L, leucine; P, proline; E, glutamic acid; O, hydroxyproline; G, glycine; CO, carbonyl. The signals from (Pα, Oα) and (Oδ, Eα) overlap in the ¹³C NMR spectrum.