The resonance Raman frequencies of the Fe-CO stretching and bending modes in the CO complex of cytochrome P-450cam.

Uno, Tadayuki; Nishimura, Yuki; Makino, Ryu; Iizuka, Tetsutarō; Ishimura, Yuzuru; Tsuboi, Masamichi

doi:10.1016/s0021-9258(18)89508-4

Cited by 77 publications

(71 citation statements)

References 25 publications

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“…FeTPPSPh-CO and PPSR-CO show ν CO at 1970 and 1965 cm –1 , respectively (Figure S5A). The ν CO stretching frequencies are substantially higher than the corresponding ν CO modes for the reduced PPSR-CO complex, at 1950 cm –1 (Figure S5B) and for CO bound ferrous Cyt P450 (at 1948 cm –1 ). − The higher energy ν CO in the ferric thiolate complexes relative to the reduced ferrous thiolate species is consistent with lower back bonding from the formally ferric center relative to the thiolate bound ferrous center. Nevertheless, the question remains how the formally ferric heme is able to mediate CO binding after all.…”

supporting

confidence: 65%

“…The rR spectrum of PPSR-CO assists in confirming the assignment of the vibrational mode at 525 cm –1 , which shifts to 523 cm –1 upon 57 Fe substitution. This feature corresponds to the Fe–C–O bending vibration (Figure ) which is substantially higher than that reported for CO bound CytP450 which appears at 481 cm –1 . , …”

mentioning

confidence: 58%

“…This feature corresponds to the Fe−C−O bending vibration (Figure 5) which is substantially higher than that reported for CO bound CytP450 which appears at 481 cm −1 . 20,21 DFT calculations provide significant insight into the electronic structures of the CO-bound ferric porphyrin species with axial thiolate ligation. The structures of the ferric precursors and their CO adducts were optimized using G09-D (BP86, 6-311G*) (Figure 6).…”

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confidence: 99%

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Formally Ferric Heme Carbon Monoxide Adduct

et al. 2019

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Formally ferric carbonyl adducts are reported in a series of thiolate-bound iron porphyrins. Resonance Raman data indicate the presence of both Fe–S and Fe–CO bonds, and EPR data of this S = 1/2 species indicate a ligand-based electron hole, giving this complex an Fe(II)-thiyl radical electronic ground state. The FTIR data show that the C–O vibrations are substantially higher than in the corresponding ferrous-thiolate CO adducts. DFT calculations reproduce the spectroscopic features and indicate that backbonding to the low lying π* orbitals of the bound CO stabilizes the Fe 3d orbitals resulting in a stabilization of the ferrous-thiyl radical ground state compared to the five-coordinate ferric-thiolate precursor complexes. Access to stable thiyl radicals will help understand these elusive species that are mostly encountered as short-lived reactive reaction intermediates.

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confidence: 65%

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confidence: 58%

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confidence: 99%

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Formally Ferric Heme Carbon Monoxide Adduct

et al. 2019

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“…Resonance Raman spectra in the region between 1000 and 1650 cm −1 , provided in Figure S1D, reveal the oxidationstate marker band (ν 4 ) at 1373 cm −1 and the spin-state marker band (ν 3 ) at 1497 cm −1 , consistent with values typically seen for these low-spin CO adducts of cytochromes P450. 62,63 The regions of the RR spectra of the Fe II −CO and Fe II − 13 CO adducts of DGCR8, wherein the ν(Fe−C) and ν(C−O) stretching modes occur, are shown in Figure 3C. In the lowerfrequency region, a clean difference pattern emerges from a ν(Fe− 12 C) mode appearing at 496 cm −1 , with its 13 C counterpart shifting to 490 cm −1 .…”

Section: ■ Results and Discussionmentioning

confidence: 97%

Analysis of Heme Iron Coordination in DGCR8: The Heme-Binding Component of the Microprocessor Complex

et al. 2016

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DGCR8 is the RNA-binding partner of the nuclease Drosha. Their complex (the "Microprocessor") is essential for processing of long, primary microRNAs (pri-miRNAs) in the nucleus. Binding of heme to DGCR8 is essential for pri-miRNA processing. On the basis of the split Soret ultraviolet-visible (UV-vis) spectrum of ferric DGCR8, bis-thiolate sulfur (cysteinate, Cys(-)) heme iron coordination of DGCR8 heme iron was proposed. We have characterized DGCR8 heme ligation using the Δ276 DGCR8 variant and combined electron paramagnetic resonance (EPR), magnetic circular dichroism (MCD), electron nuclear double resonance, resonance Raman, and electronic absorption spectroscopy. These studies indicate DGCR8 bis-Cys heme iron ligation, with conversion from bis-thiolate (Cys(-)/Cys(-)) axial coordination in ferric DGCR8 to bis-thiol (CysH/CysH) coordination in ferrous DGCR8. Pri-miRNA binding does not perturb ferric DGCR8's optical spectrum, consistent with the axial ligand environment being separated from the substrate-binding site. UV-vis absorption spectra of the Fe(II) and Fe(II)-CO forms indicate discrete species exhibiting peaks with absorption coefficients substantially larger than those for ferric DGCR8 and that previously reported for a ferrous form of DGCR8. Electron-nuclear double resonance spectroscopy data exclude histidine or water as axial ligands for ferric DGCR8 and favor bis-thiolate coordination in this form. UV-vis MCD and near-infrared MCD provide data consistent with this conclusion. UV-vis MCD data for ferrous DGCR8 reveal features consistent with bis-thiol heme iron coordination, and resonance Raman data for the ferrous-CO form are consistent with a thiol ligand trans to the CO. These studies support retention of DGCR8 cysteine coordination upon reduction, a conclusion distinct from those of previous studies of a different ferrous DGCR8 isoform.

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“…The interpretation of the SERRS data has been aided by normal coordinate analyses of porphyrin model compounds (Abe et al, 1978), labeling studies of heme proteins (Hu et al, 1993), and comparative resonance Raman data from mammalian (Hildebrandt, 1991; and bacterial cytochromes-P450 (Hildebrandt and Stockburger, 1986;Wells et al, 1992;Uno et al, 1985). In addition to information on the oxidation, spin, and ligation state of the heme, SERRS indicates subtle structural distortion of the heme on substrate binding.…”

Section: Introductionmentioning

confidence: 99%

Fatty Acid-Induced Alteration of the Porphyrin Macrocycle of Cytochrome P450 BM3

Macdonald

Munro

Smith

1998

Biophysical Journal

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Surface-enhanced resonance Raman scattering (SERRS) of substrate-free and substrate-bound forms of the P450 domain of cytochrome P450 BM3 are reported and assigned. Substrate-free P450 yields mixed spin heme species in which the pentacoordinate high-spin arrangement is dominant. The addition of laurate or palmitate leads to an increase in high spin content and to an allosteric activation of heme mode v29, which is sensitive to peripheral heme/protein interactions. Differences between laurate and palmitate binding are observed in the relative intensities of a number of bands and the splitting of the heme vinyl modes. Laurate binding to P450 results in different protein environments being experienced by each vinyl mode, whereas palmitate binding produces a smaller difference. The results demonstrate the ability of SERRS to probe substrate/prosthetic group interactions within an active site, at low protein concentrations.

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The resonance Raman frequencies of the Fe-CO stretching and bending modes in the CO complex of cytochrome P-450cam.

Cited by 77 publications

References 25 publications

Formally Ferric Heme Carbon Monoxide Adduct

Formally Ferric Heme Carbon Monoxide Adduct

Analysis of Heme Iron Coordination in DGCR8: The Heme-Binding Component of the Microprocessor Complex

Fatty Acid-Induced Alteration of the Porphyrin Macrocycle of Cytochrome P450 BM3

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