Solution Structure of Oxidized Horse Heart Cytochrome c^,

Abstract

The solution structure of oxidized horse heart cytochrome c was obtained at pH 7.0 in 100 mM phosphate buffer from 2278 NOEs and 241 pseudocontact shift constraints. The final structure was refined through restrained energy minimization. A 35-member family, with RMSD values with respect to the average structure of 0.70 ( 0.11 Å and 1.21 ( 0.14 Å for the backbone and all heavy atoms, respectively, and with an average penalty function of 130 ( 4.0 kJ/mol and 84 ( 3.7 kJ/mol for NOE and pseudocontact shift constraints, respectively (corresponding to a target function of 0.9 Å 2 and 0.2 Å 2 ), was obtained. The solution structure is somewhat different from that recently reported (Qi et al., 1996) and appears to be similar to the X-ray structure of the same oxidation state (Bushnell et al., 1990). A noticeable difference is a rotation of 17 ( 8°of the imidazole plane between solid and solution structure. Detailed and accurate structural determinations are important within the frame of the current debate of the structural rearrangements occurring upon oxidation or reduction. From the obtained magnetic susceptibility tensor a separation of the hyperfine shifts into their contact and pseudocontact contributions is derived and compared to that of the analogous isoenzyme from S. cereVisiae and to previous results.

The effects of ATP and sodium chloride on the cytochrome c–cardiolipin interaction: The contrasting behavior of the horse heart and yeast proteins

“…Thus, the cyt c-CL interaction plays an important role in cells since it modulates the protein behavior determining whether cyt c should perform its 'normal' role in the respiratory chain or, conversely, is to be released into the cytosol where it participates in the apoptotic event (see [40] and references therein). Unlike the equine protein, cyt c from yeast does not participate in cell apoptosis [16,17].…”

“…The two proteins have a similar tertiary architecture [14][15][16][17], but yeast cyt c displays a significantly lower stability than the protein from horse, it does not bind ATP and, contrary to horse cyt c, lacks pro-apoptotic activity [18,19]. The CL-cyt c binding reaction has been investigated in the absence and in the presence of ATP and sodium chloride, two compounds that significantly influence the (horse cyt c)-CL binding process [5].…”

Covalent Adducts Arising from the Decomposition Products of Lipid Hydroperoxides in the Presence of Cytochrome c

“…It is also highly conserved between species and is well characterized structurally by X-ray crystallography and NMR (15)(16)(17)(18). In addition, its location in the inner membrane of the mitochondria, a highly oxidizing environment, makes it a potential target in vivo.…”

Role of Lysines in Cytochrome c–Cardiolipin Interaction

“…Detail of the salt bridges (right) anchoring Lys73 to Glu66 and Glu69. This figure has been generated using the horse heart cyt c threedimensional structure deposited in the Protein Data Bank as entry 1AKK 46 with UCSF Chimera. 47 formation, the CL binding to cyt c involves electrostatic interactions of CL phosphate groups with Lys79 and Lys72.…”