Ferrocytochrome solution structure

Recently, Sivakolundu and Mabrouk published an NMR solution structure of horse heart ferrocytochrome c in which the heme contains an Fe(II) ion. This solution structure was the first in which the cytochrome c protein was dissolved in a nonaqueous solvent a solvent mix of 70% water and 30% acetonitrile (ACN). The data obtained from the NMR study are deposited in the protein data bank (PDB) as (1) ILCl, the minimized average NMR structure and (2) 1LC2, the 30 lowest energy NMR structures. 

The X-ray crystal structure of D. vulgaris (Hildenborough) ferricytochrome c3 is known [51] and a preliminary solution structure for the ferrocytochrome has been obtained by NMR [58]. Also, the reduction potentials for each of its four hemes, as well as the specific assignment to their position in the structure... 

Although cytochrome c oxidase from S. novella is cytochrome aa3-type, its molecular features are very unique (Shoji et al., 1992). In general, cytochrome aa3-type oxidase has two heme A molecules and 2-3 copper atoms in the minimal structural unit, while the S. novella oxidase has one heme A molecule and one copper atom in the minimal structural unit constituted of two subunits (32 and 23 kDa). The oxidase occurs as the monomer of the minimal structural unit in the solution containing 0.5% n-octyl-D-P-thioglucoside (OTG). The monomer catalyzes the rapid oxidation of ferrocytochrome c, its heme A molecule reacts completely with carbon monoxide (CO) under 100% carbon monoxide atmosphere, and its copper shows a big signal at g = 2.01 in EPR spectrum the monomer seems to be a cytochrome a3 having Cua (Shoji et al., 1992). 

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