Previous studies have shown that relaxation parameters and fast protein dynamics can be quickly elucidated from 15N-CEST experiments . Longitudinal R1 and transverse R2 values were reliably derived from fitting of CEST profiles. Herein we show that 15N-CEST experiments and traditional modelfree analysis provide the internal dynamics of three states of human protein DJ-1 at physiological temperature. The chemical exchange profiles show the absence of a minor state conformation and, in conjunction with 1H-15N NOEs, show increased mobility. R1 and R2 values remained relatively unchanged at the three naturally occurring oxidation states of DJ-1, but exhibit striking NOE differences. The NOE data was, therefore, essential in determining the internal motions of the DJ-1 proteins. To the authors' knowledge, we present the first study that combines 15N CEST data with traditional model-free analyses in the study of a biological system and affirm that more ‘lean’ model-free approaches should be used cautiously.
Catazaro, J., Andrews, T., Milkovic, N. M., Lin, J., Lowe, A. J., Wilson, M. A., & Powers, R. (2018). 15N CEST data and traditional model-free analysis capture fast internal dynamics of DJ-1. Analytical Biochemistry, 542, 24–28. https://doi.org/10.1016/j.ab.2017.11.012