scholarly journals Review: Studies of ferric heme proteins with highly anisotropic/highly axial low spin (S= 1/2) electron paramagnetic resonance signals with bis-Histidine and histidine-methionine axial iron coordination

Biopolymers ◽  
2009 ◽  
Vol 91 (12) ◽  
pp. 1064-1082 ◽  
Author(s):  
Giorgio Zoppellaro ◽  
Kara L. Bren ◽  
Amy A. Ensign ◽  
Espen Harbitz ◽  
Ravinder Kaur ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Heme Proteins ◽  
Paramagnetic Resonance ◽  
Iron Coordination ◽  
Ferric Heme ◽  
Electron Paramagnetic

scholarly journals The Effects of Protein Conformation on the Heme Symmetry in High Spin Ferric Heme Proteins as Studied by Electron Paramagnetic Resonance

1971 ◽  
Vol 246 (10) ◽  
pp. 3342-3355 ◽  
Author(s):  
J. Peisach ◽  
W.E. Blumberg ◽  
S. Ogawa ◽  
E.A. Rachmilewitz ◽  
R. Oltzik
Keyword(s):  
Electron Paramagnetic Resonance ◽  
High Spin ◽  
Protein Conformation ◽  
Heme Proteins ◽  
Paramagnetic Resonance ◽  
Ferric Heme ◽  
Electron Paramagnetic

The pH-Induced Transition of Iodinated Ferricytochrome c: Electron Paramagnetic Resonance and Absorption Spectra

1973 ◽  
Vol 51 (4) ◽  
pp. 472-475 ◽  
Author(s):  
R. A. Morton
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Liquid Nitrogen Temperature ◽  
Heme Iron ◽  
Paramagnetic Resonance ◽  
Frozen Solution ◽  
Type Iii ◽  
Type Iv ◽  
Ferricytochrome C ◽  
Iron Coordination ◽  
Electron Paramagnetic

The heme-associated, pH-induced transition in iodinated ferricytochrome c has been studied by electron paramagnetic resonance (E.P.R.) and absorption spectroscopy. The conversion from type III to type IV (as defined by Theorell, H., and Åkesson, Å.: J. Am. Chem. Soc. 63, 1812 (1941)) ferricytochrome c forms was dramatically altered by iodination of tyrosyl residues. Both absorption and E.P.R. spectra suggested that a transition between similar heme-iron coordination structures occurred with a pK of about 6 as compared with about 9 for native ferricytochrome c. At pH 4.4 the E.P.R. spectrum (liquid nitrogen temperature) of a frozen solution of iodinated ferricytochrome c was similar to the native type III at pH 7, except for an increased g = 6.0 signal from high-spin heme iron. At neutral pH the E.P.R. spectrum of the iodinated derivative was similar to type IV ferricytochrome c. The results give further support to the hypothesis that the pK of tyrosine 67 plays an important role in determining the pK of the III to IV transition.

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