FIGURE 6.

Qualitative comparison of backbone conformation and dynamics for wild-type WTX, rWTX, and rWTX(P33A). A, relative intensity of ¹⁵N-HSQC signals for trans and cis forms of rWTX and rWTX(P33A) mutant. For clarity, the intensities for two forms of rWTX are shown in joint columns. Residues with unassigned HN resonances and prolines are marked by crosses. B, difference of ¹H^N and ¹H^α chemical shifts between wild-type WTX and rWTX (trans and cis forms) at pH ∼3.0 and 40 °C. The arbitrarily chosen threshold values (0.05 and 0.03 ppm for ¹H^N and ¹H^α, respectively) are shown. C, comparison of ³J_H^N_H^α couplings measured for the trans form of native WTX and rWTX(P33A). The values with difference exceeding 2 Hz are connected by vertical lines. Uncertainties in the measured ³J_H^N_H^α values do not exceed 1 Hz. Chemical shifts and J-coupling constants for trans and cis forms of wild-type WTX were taken from Ref. 30.