Binding of Yeast Cytochrome c to Forty-Four Charge-Reversal Mutants of Yeast Cytochrome c Peroxidase: Isothermal Titration Calorimetry

Biochemistry ◽  
2015 ◽  
Vol 54 (31) ◽  
pp. 4845-4854 ◽  
Author(s):  
James E. Erman ◽  
Lidia B. Vitello ◽  
Naw May Pearl ◽  
Timothy Jacobson ◽  
Meka Francis ◽  
...  
1997 ◽  
Vol 243 (1-2) ◽  
pp. 72-84 ◽  
Author(s):  
Jordi Bujons ◽  
Alexander Dikiy ◽  
Juan C. Ferrer ◽  
Lucia Banci ◽  
A. Grant Mauk

1994 ◽  
Vol 302 (2) ◽  
pp. 437-442 ◽  
Author(s):  
S F DeLauder ◽  
J M Mauro ◽  
T L Poulos ◽  
J C Williams ◽  
F P Schwarz

The thermodynamics of binding of fluoride and cyanide to cytochrome c peroxidase (CCP) and its Asn-82-->Asp mutant (D82CCP) in phosphate and acetate buffer at an ionic strength of 0.15 mol.kg-1 from pH 5.0 to 7.1 were investigated by titration calorimetry at 289 and 297 K. The binding reactions are enthalpically driven. The fluoride-binding constants determined from the titration calorimetry results were in agreement with those determined from difference-spectroscopy measurements. For cyanide binding to CCP at 297.9 K, the binding constant decreased from 8.95 (+/- 0.83) x 10(5) M-1 at pH 7.0 to 4.04(+/- 0.23) x 10(5) M-1 at pH 5.0, and the binding enthalpy increased from -57.2 +/- 1.4 kJ.mol-1 at pH 7.0 to -48.6 +/- 1.8 kJ.mol-1 at pH 5.0. For fluoride binding to CCP, the binding constant increased from 8.41(+/- 0.54) x 10(3) M-1 at pH 7.0 to 3.11(+/- 0.09) x 10(5) M-1 at pH 5.0 and the binding enthalpy increased from -71.9 +/- 1.1 kJ.mol-1 at pH 7.0 to -67.0 +/- 1.9 kJ.mol-1 at pH 5.0. The binding enthalpies for D82CCP were about the same as those for CCP. However, the binding constants for cyanide and fluoride to D82CCP were respectively a factor of two less and at least an order of magnitude less than the corresponding binding constants of CCP. Decreased ligand-binding strength in the D82CCP mutant is thus entirely due to entropic effects.


2003 ◽  
Vol 410 (2) ◽  
pp. 230-237 ◽  
Author(s):  
Moonjoo Koh ◽  
Terry E Meyer ◽  
Lina De Smet ◽  
Jozef J Van Beeumen ◽  
Michael A Cusanovich

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