One- and two-dimensional NMR characterization of oxidized and reduced cytochrome c' from Rhodocyclus gelatinosus

Abstract

1D and 2D NMR spectra of both the reduced and oxidized forms of cytochrome c' from Rhodocyclus gelatinosus have been recorded. The analysis of the pH dependence of the 1H NMR spectrum of the ferric form has been performed, and two main ionizing groups have been identified. By comparison of the pH dependence of the available spectra of cytochromes c', an ambiguity remaining from previous studies on related cytochromes c' has been solved. By means of 2D spectra, an assignment of all the paramagnetically shifted signals is proposed both for the ferrous and for the ferric forms.

1H‐NMR study of reduced heme proteins myoglobin and cytochrome P450

“…The methyl T, values in the cyanide derivatives of iron(II1) metmyoglobin and peroxidases are about 100 ms and 50 ms, respectively, i.e. of the same order as those found in reduced Mb and in reduced cytochrome c' [34]. This means that the electron-relaxation times of high-spin iron(I1) have to be approximately six-times smaller than in low-spin iron(1II) owing to the different S values [45].…”

“…Reduced cytochrome c' species. which have a histidine as axial ligand, show three CH, signals upfield and one downfield [34,[47][48][49]. In reduced Mb from different sources [19] two CH, signals are found downfield and two are hidden under the diamagnetic envelope.…”

Electrochemical and NMR spectroscopic studies of distal pocket mutants of nitrophorin 2: Stability, structure, and dynamics of axial ligand complexes

“…2, where it can be seen that unique resonances, most of which have intensities corresponding to one or three protons, are observed that are similar in general appearance to those of previously studied high-spin Fe(III) proteins (36), especially horseradish peroxidase (36,44,45) and cytochrome cЈ (36,(46)(47)(48). The assigned heme methyl and propionate resonances of NP2 (34) and its distal pocket mutants are labeled.…”

High resolution crystal structure of Rubrivivax gelatinosus cytochrome c′

“…Early magnetic susceptibility measurements on cytochromes c 0 were interpreted with a physical model that implied a thermal equilibrium between the low spin (S = 1/2) and the high-spin (S = 5/2) states [22]. Later, optical [23], near infrared [24], near infrared MCD [25], Mössbauer [26], and NMR [27][28][29][30][31][32] data suggested that cytochrome c 0 is substantially high-spin (S = 5/2) at neutral pH. In contrast to both hypotheses above, EPR [33][34][35][36][37][38][39][40], Mössbauer [41], optical [42], NMR [43] and resonance Raman [44] results were interpreted with the hypothesis of a quantum mechanical admixture of a high-spin (S = 5/2) and an intermediate spin (S = 3/2) state.…”