Figure 6. Magnetic field-dependence of the ¹⁵N transverse relaxation rates for the resonances of the major slow exchange conformation in the wild-type and C22V variant of FKBP12 at 25°C.

(A) R₂ values for the wild-type FKBP12 at 600 MHz ¹H (black) and 800 MHz ¹H (red). Residues not undergoing conformational exchange-dependent line-broadening exhibit field-dependent increases in R₂ values of ~23%. (B) R₂ values for the C22V variant of FKBP12 at 600 MHz ¹H (black) and 800 MHz ¹H (red). Relaxation data are not reported for the severely broadened resonances of Tyr⁸² (conformational exchange broadening), Ala⁸⁴ (amide hydrogen exchange broadening) and Gly⁸⁹ (both).