Paramagnetic properties of the low- and high-spin states of yeast cytochrome c peroxidase

J Biomol NMR. 2013 Sep;57(1):21-6. doi: 10.1007/s10858-013-9760-8. Epub 2013 Jul 6.

Abstract

Here we describe paramagnetic NMR analysis of the low- and high-spin forms of yeast cytochrome c peroxidase (CcP), a 34 kDa heme enzyme involved in hydroperoxide reduction in mitochondria. Starting from the assigned NMR spectra of a low-spin CN-bound CcP and using a strategy based on paramagnetic pseudocontact shifts, we have obtained backbone resonance assignments for the diamagnetic, iron-free protein and the high-spin, resting-state enzyme. The derived chemical shifts were further used to determine low- and high-spin magnetic susceptibility tensors and the zero-field splitting constant (D) for the high-spin CcP. The D value indicates that the latter contains a hexacoordinate heme species with a weak field ligand, such as water, in the axial position. Being one of the very few high-spin heme proteins analyzed in this fashion, the resting state CcP expands our knowledge of the heme coordination chemistry in biological systems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cytochrome-c Peroxidase / analysis
  • Cytochrome-c Peroxidase / chemistry*
  • Electron Spin Resonance Spectroscopy / methods*
  • Hemeproteins / chemistry*
  • Mitochondria / enzymology
  • Nuclear Magnetic Resonance, Biomolecular / methods*
  • Yeasts / enzymology*

Substances

  • Hemeproteins
  • Cytochrome-c Peroxidase