Figure 3.

The aromatic to sugar H1′ region of a D₂O NOESY (300 ms mixing time) spectrum of tP5abc recorded at 25°C. The spectrum was constructed by overlapping the identical regions of both sides of the diagonal (cross-peaks are colored in purple and black). The aromatic to H1′ sequential NOE connectivity walks colored in red, green, and blue correspond to P5c, P5a, and P5b, respectively. The free induction decay was recorded on an 800-MHz Varian NMR spectrometer and processed by using FELIX95 (Biosym Technologies). The small spectrum insert at around 7.0 ppm (D1) and 5.9 ppm (D2) is the identical region of a D₂O NOESY (300 ms mixing time) spectrum recorded at 10°C. The H1′ resonance frequencies of residue A140 and G180 are degenerate at 25°C, but clearly resolved at 10°C. Because the two cross-peaks in the spectrum insert are well separated from the crowed region, the assignment is unambiguous.