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Changes in secondary structure and salt links of cytochrome P-450cam induced by photoreduction: a Fourier transform infrared spectroscopic study

Item Type:Article
Title:Changes in secondary structure and salt links of cytochrome P-450cam induced by photoreduction: a Fourier transform infrared spectroscopic study
Creators Name:Contzen, J. and Jung, C.
Abstract:Tris(2,2'-bipyridyl)ruthenium(II) was used as a light-induced artificial electron donor for the transfer of the first electron to cytochrome P-450(cam) bound with (1R)-camphor and camphane substrates, and in the substrate-free form. Fourier transform infrared spectroscopy was used to detect changes of the amide I' band and the CO ligand stretch vibration of heme-bound carbon monoxide associated with the heme redox transition. The reduced-minus-oxidized difference spectra show that not only the heme group but also the protein backbone and individual amino acid side chains were affected by the redox transition. Observed secondary structure changes were almost identical for (1R)-camphor-bound and camphane-bound cytochrome P-450(cam), with a remarkable negative signal at 1724.3 cm(-)(1) and a positive signal at 1716.0 cm(-)(1). These signals were not observed in substrate-free P-450(cam). On the basis of known crystallographic data, we assign these signals to a change of hydrogen bonds of a salt link between Arg112, His355, and the heme 6-propionic group.
Keywords:2,2'-Dipyridyl, Binding Sites, Bornanes, Camphor 5-Monooxygenase, Carbon Monoxide, Chemical Models, Edetic Acid, Electron Transport, Ferrous Compounds, Fourier Transform Infrared Spectroscopy, Organometallic Compounds, Oxidation-Reduction, Photolysis, Pseudomonas Putida, Ruthenium, Salts, Secondary Protein Structure, Substrate Specificity, Ultraviolet Spectrophotometry
Source:Biochemistry
ISSN:0006-2960
Publisher:American Chemical Society (U.S.A.)
Volume:38
Number:49
Page Range:16253-16260
Date:7 December 1999
Official Publication:https://doi.org/10.1021/bi991759u
PubMed:View item in PubMed

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