Roldán M D, Sears H J, Cheesman M R, Ferguson S J, Thomson A J, Berks B C, Richardson D J
School of Biological Sciences, Centre for Metalloprotein Spectroscopy and Biology, University of East Anglia, Norwich, UK.
J Biol Chem. 1998 Oct 30;273(44):28785-90. doi: 10.1074/jbc.273.44.28785.
NapC is a member of a family of bacterial membrane-anchored tetra-heme c-type cytochromes that participate in a number of respiratory electron transport pathways. They are postulated to mediate electron transfer between membrane quinols/quinones and soluble periplasmic enzymes. The water-soluble heme domain of NapC has been expressed as a periplasmic protein. Mediated redox potentiometry and characterization by UV-visible, magnetic circular dichroism, and electron paramagnetic resonance spectroscopies demonstrates that soluble NapC contains four low spin hemes, each with bis-histidine axial ligation and with midpoint reduction potentials of -56, -181, -207, and -235 mV.
NapC是细菌膜锚定四血红素c型细胞色素家族的成员，参与多种呼吸电子传递途径。据推测，它们介导膜醌/醌类与可溶性周质酶之间的电子转移。NapC的水溶性血红素结构域已作为周质蛋白表达。通过紫外可见光谱、磁圆二色光谱和电子顺磁共振光谱进行的介导氧化还原电位测定和表征表明，可溶性NapC含有四个低自旋血红素，每个血红素都有双组氨酸轴向配体，中点还原电位分别为-56、-181、-207和-235 mV。
