Near-Infrared Magnetic Circular Dichroism Of Heme Proteins

1989 ◽  
Author(s):  
P. J. Stephens
Keyword(s):  
Circular Dichroism ◽  
Heme Proteins ◽  
Near Infrared ◽  
Magnetic Circular Dichroism ◽  
Circular Dichroïsm

scholarly journals The nature of haem a3 in the oxidized state of cytochrome c oxidase. Evidence from low-temperature magnetic-circular-dichroism spectroscopy in the near infrared region

1982 ◽  
Vol 207 (1) ◽  
pp. 167-170 ◽  
Author(s):  
A J Thomson ◽  
D G Englinton ◽  
B C Hill ◽  
C Greenwood
Keyword(s):  
Circular Dichroism ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Near Infrared ◽  
Magnetic Circular Dichroism ◽  
Infrared Region ◽  
Magnetic Circular Dichroism Spectroscopy ◽  
Near Infrared Region ◽  
Circular Dichroïsm ◽  
Inhibited Enzyme

The magnetic-circular-dichroism (m.c.d.) spectra of oxidized ‘resting’ bovine cytochrome c oxidase and the cyanide-inhibited form are reported at 5.15 T and at 4.2 K along with m.c.d. magnetization curves plotted at selected wavelengths. In both spectra there are features at 790nm and 1564nm due to Cua and haem a respectively, the e.p.r.-detectable components of the enzyme. There is a new peak at 1946nm only in the spectrum of the cyanide-inhibited enzyme. Arguments are advanced that assign this to low-spin ferric haem a3 bridged to Cua3, thereby forming a ferromagnetically coupled pair of metal ions.

scholarly journals Origins and Spin Dependence of Near Infrared Magnetic Circular Dichroism of Iron(III) Hemoproteins

1982 ◽  
Vol 55 (10) ◽  
pp. 3059-3063 ◽  
Author(s):  
Takao Yamamoto ◽  
Tsunenori Nozawa ◽  
Nagao Kobayashi ◽  
Masahiro Hatano
Keyword(s):  
Circular Dichroism ◽  
Near Infrared ◽  
Magnetic Circular Dichroism ◽  
Spin Dependence ◽  
Circular Dichroïsm

Near-infrared magnetic circular dichroism of cytochrome c'

Biochemistry ◽  
1977 ◽  
Vol 16 (8) ◽  
pp. 1725-1729 ◽  
Author(s):  
J. Rawlings ◽  
P. J. Stephens ◽  
L. A. Nafie ◽  
M. D. Kamen
Keyword(s):  
Circular Dichroism ◽  
Cytochrome C ◽  
Near Infrared ◽  
Magnetic Circular Dichroism ◽  
Circular Dichroïsm

scholarly journals Characterization of the partially reduced cyanide-inhibited derivative of cytochrome c oxidase by optical, electron-paramagnetic-resonance and magnetic-circular-dichroism spectroscopy

1981 ◽  
Vol 193 (3) ◽  
pp. 699-708 ◽  
Author(s):  
M K Johnson ◽  
D G Eglinton ◽  
P E Gooding ◽  
C Greenwood ◽  
A J Thomson
Keyword(s):  
Circular Dichroism ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Near Infrared ◽  
Magnetic Circular Dichroism ◽  
Circular Dichroism Spectroscopy ◽  
Paramagnetic Resonance ◽  
Magnetic Circular Dichroism Spectroscopy ◽  
Circular Dichroïsm ◽  
Reduced State

Optical. e.p.r. and near-infrared low-temperature m.c.d. (magnetic-circular-dichroism) spectroscopy were used to characterize the partially reduced cyanide-inhibited derivative of cytochrome c oxidase produced by anaerobic reductive titration with dithionite. The reductions of cytochrome a3+ and Cu2+a were followed by observation of the e.p.r. signals at g = 3.03, 2.21 and 1.5 and at g = 2.18, 2.03 and 1.99. As reduction proceeds new e.p.r. signals (g = 3.58 and 1.56) appear that quantify to give one haem per enzyme unit when a small excess of dithionite has been titrated in. The e.p.r. signal of the Cu2+a titrates in parallel with the disappearance of the band and 820nm in the optical absorption spectrum. The near-infrared m.c.d. spectrum shows the presence of the low-spin ferric haem, a3+, in the oxidized state of the enzyme, as a well-resolved positive peak at 1650nm. As reduction proceeds this band is replaced by one at 1550nm due to haem a3+(3)–CN in the partially reduced state. Hence as haem a3+(3)–CN becomes e.p.r.-detectable it also shows a near-infrared m.c.d. spectrum characteristic of a low-spin ferric haem. It is concluded that the partially reduced state of cyanide-inhibited cytochrome c oxidase contains a2+ . Cu+a . a3+(3)–CN . Cu+a3.

The axial ligands of heme in cytochromes: a near-infrared magnetic circular dichroism study of yeast cytochromes c, c1, and b and spinach cytochrome f

Biochemistry ◽  
1989 ◽  
Vol 28 (20) ◽  
pp. 8033-8039 ◽  
Author(s):  
David Simpkin ◽  
Graham Palmer ◽  
F. J. Devlin ◽  
M. C. McKenna ◽  
G. M. Jensen ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Near Infrared ◽  
Magnetic Circular Dichroism ◽  
Cytochrome F ◽  
Axial Ligands ◽  
Cytochromes C ◽  
Circular Dichroïsm
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