NMR data of V75D γD-crystallin in 4.2 M urea. (A) Cα and Cβ secondary chemical shifts of the NTD. (B) Selected region of the 3D IPAP-HNCO spectrum recorded for V75D γD-crystallin, aligned in a stretched polyacrylamide gel in the presence of 4.2 M urea. Superposition of representative upfield (gray) and downfield (black) components for the doublets, recorded in separate sub-spectra, are shown for Ser19, Ser20, Asp73, and Asp75, all in the NTD. The labeled crosspeaks are located at δCO = 174.6 ppm, and the unlabeled weaker crosspeaks are from residues centered on nearby carbonyl planes. (C) Experimentally measured RDC values versus position in the amino acid sequence of V75D γD-crystallin in 4.2 M urea. The dashed gray line marks the boundary between the NTD and CTD.