view article
Figure 3
Typical UV–Vis spectra of (a) ferric (oxidized) and (b) ferrous (reduced) forms of the TtX183 domains. Spectra for TtX183A, TtX183B and TtX183C are shown in blue, red and green, respectively. The α- and β-bands display maxima at 523 and 552 nm in the ferrous state, which flatten out to a broad peak when oxidized. The Soret band also shifts from 419 to 409 nm upon oxidation. All three spectra overlay very closely demonstrating that each X183 domain possesses similar haem environments and electronic characteristics. (c) Characteristic CVs at pH 7.0 for protein films of TtX183A, TtX183B and TtX183C on a pyrolytic graphite-edge working electrode coloured as in (a) and (b). Blank measurements for the pyrolytic graphite-edge working electrode in the absence of protein film are shown in grey. The midpoint potentials of the redox couples observed in the CVs are used to determine the reduction potentials of the haem iron in each domain.

IUCrJ
Volume 11| Part 2| March 2024| Pages 260-274
ISSN: 2052-2525
https://doi.org/10.1107/S2052252524001386