Department of Molecular Biosciences, University of Oslo, Oslo, Norway.
PLoS One. 2011;6(7):e22014. doi: 10.1371/journal.pone.0022014. Epub 2011 Jul 18.
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 c(2), 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 g(max) at 3.40, and ligand field parameters V/ξ = 0.99, Δ/ξ = 4.57. This gives the rhombicity V/Δ = 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.
从 Methylosinus trichosporium OB3b 中纯化出的一种小可溶性细胞色素 c-554 已通过氨基酸测序、质谱、可见光谱、CD 和 EPR 光谱进行了纯化和分析。它被发现是一种单血红素蛋白，具有特征性的细胞色素 c 折叠，因此属于细胞色素 c(2)类，这是线粒体细胞色素 c 的细菌同源物。亚铁血红素具有组氨酸/蛋氨酸轴向配位，表现出高度各向异性/轴向低自旋（HALS）EPR 信号，g(max) 在 3.40 处，配体场参数 V/ξ = 0.99，Δ/ξ = 4.57。这给出了菱形比 V/Δ = 0.22。组氨酸/蛋氨酸配位血红素中这种 HALS EPR 信号的结构基础尚未解决。观察到的细胞色素 c-554 的配体场参数符合具有类似配位和 EPR 行为的其他细胞色素的观察模式。
