Heteronuclear three-dimensional NMR spectroscopy of a partially denatured protein: the A-state of human ubiquitin.

Human ubiquitin is a 76-residue protein that serves as a protein degradation signal when conjugated to another protein. Ubiquitin has been shown to exist in at least three states: native (N-state), unfolded (U-state), and, when dissolved in 60% methanol:40% water at pH 2.0, partially folded (A-state).

1H and 15N resonance assignments and solution secondary structure of oxidized Desulfovibrio vulgaris flavodoxin determined by heteronuclear three-dimensional NMR spectroscopy.

Sequence-specific 1H and 15N resonance assignments have been made for all 145 non-prolyl residues and for the flavin cofactor in oxidized Desulfovibrio vulgaris flavodoxin. Assignments were obtained by recording and analyzing 1H-15N heteronuclear three-dimensional NMR experiments on uniformly 15N-enriched protein, pH 6.5, at 300 K.