FIG. 4.

Influence of oxidative stress on inter spin distances in HbpS. (A, C, E) Background corrected dipolar evolution data (the raw DEER traces together with the background fits are shown in Supplementary Fig. S2 in Supplementary Materials) and corresponding fits obtained by Tikhonov regularization for unstressed (green) and stressed (blue) samples of the respective HbpS mutant. For Gly71R1/Ser139R1 (E), in addition, the low-temperature cw spectrum with the respective fit obtained with DipFit (33) is shown. (B, D, F) Distance distributions obtained by Tikhonov regularization: unstressed–green, stressed–blue. The distance distribution obtained from the low-temperature cw experiment for Gly71R1/Ser139R1 is shown as a broken line (F). The results of the rotamer library analyses are shown in red (PDB: 3FPV, native HbpS) and purple (PDB: 3FPW, HbpS-iron complex). (To see this illustration in color the reader is referred to the web version of this article at www.liebertonline.com/ars).