15N, 13C, and 1H NMR assignments and secondary structure for T4-lysozyme

Sequence-specific 1H, 13C, and 15N backbone assignments and 1H and 13C side-chain assignments have been identified for T4-lysozyme (164 residues, MW = 18.7 kDa). A variety of double- and triple-resonance 3D techniques were used. Some of these methods were applied in unconventional ways and a detailed description of the advantages and disadvantages of these approaches is given. Complete backbone resonances for 162 of the 164 residues and partial assignments for the remaining 2 residues were obtained. The 1H and 15N assignments are in agreement with those obtained previously by McIntosh et al. who used selective labeling (L.P. McIntosh et al., Biochemistry 29, 6341 (1990)). Complete proton and carbon side-chain assignments were made for 120 residues and partial side-chain assignments were made for 42 additional residues. A qualitative analysis of the medium-range NOESY data reveals a secondary structure consistent with the X-ray crystallographic structure.