cytochrome c-554 from methylosinus trichosporium ob3b; a protein that belongs to the cytochrome c2 family and exhibits a hals-type epr signal细胞色素c - 554从methylosinus trichosporium ob3b;.pdf

Cytochrome c-554 from Methylosinus trichosporium OB3b; a Protein That Belongs to the Cytochrome c2 Family and Exhibits a HALS-Type EPR Signal Espen Harbitz, K. Kristoffer Andersson* Department of Molecular Biosciences, University of Oslo, Oslo, Norway Abstract A small soluble cytochrome c-554 purified from Methylosinus trichosporium OB3b has been purified and analyzed by amino acid sequencing, mass spectrometry, visible, CD and EPR spectroscopies. It is found to be a mono heme protein with a characteristic cytochrome c fold, thus fitting into the class of cytochrome c2, which is the bacterial homologue of mitochondrial cytochrome c. The heme iron has a Histidine/Methionine axial ligation and exhibits a highly anisotropic/axial low spin (HALS) EPR signal, with a gmax at 3.40, and ligand field parameters V/j = 0.99, D/j = 4.57. This gives the rhombicity V/D = 0.22. The structural basis for this HALS EPR signal in Histidine/Methionine ligated hemes is not resolved. The ligand field parameters observed for cytochrome c-554 fits the observed pattern for other cytochromes with similar ligation and EPR behaviour. Citation: Harbitz E, Andersson KK (2011) Cytochrome c-554 from Methylosinus trichosporium OB3b; a Protein That Belongs to the Cytochrome c2 Family and Exhibits a HALS-Type EPR Signal. PLoS ONE 6(7): e22014. doi:10.1371/journal.pone.0022014 Editor: Andreas Hofmann, Griffith University, Australia Received May 9, 2011; Accepted June 10, 2011; Published July 18, 2011 Copyright: 2011 Harbitz, Andersson. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This research was funded by the Norwegian Research Council (grant number 157855 [to EH] and gr