Resonance Raman investigation of nitric oxide bonding in iron porphyrins: detection of the Fe-NO stretching vibration

Lipscomb, Leigh Ann; Lee, Bao Shiang; Yu, Nai‐Teng

doi:10.1021/ic00055a009

Cited by 32 publications

(39 citation statements)

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“…Indeed, published reports of RR spectra of 6-c adducts have frequencies which are characteristic of 5-c adducts. 17,18 We infer that the Raman laser induces dissociation of the weak Fe-ligand bond, either photolytically or via local heating.…”

Section: Resultsmentioning

confidence: 91%

Differential Sensing of Protein Influences by NO and CO Vibrations in Heme Adducts

2006

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Heme proteins bind the gaseous ligands XO (X = C, N, O) via backbonding from Fe d π electrons. Backbonding is modulated by distal interactions of the bound ligand with the surrounding protein and by variations in the strength of the trans proximal ligand. Vibrational modes associated with FeX and XO bond stretching coordinates report on these interactions, but the interpretive framework developed for CO adducts, involving anticorrelations of νFeC and νCO, has seemed not to apply to NO adducts. We have now obtained an excellent anticorrelation of νFeN and νNO, via resonance Raman spectroscopy on (N-methylimidazole)Fe(II)TPP-Y(NO), where TPP-Y is tetraphenylporphine with electron donating or withdrawing substituents, Y, that modulate the backbonding; the problem of laser-induced dissociation of the axial base was circumvented by using frozen solutions. New data are also reported for CO adducts. The anticorrelations are supported by DFT calculations of structures and spectra. When protein data are examined, the NO adducts show large deviations from the modeled anticorrelation when there are distal H-bonds or positive charges. These deviations are proposed to result from closing of the FeNO angle due to a shift in the valence isomer equilibrium toward the Fe(III)(NO -) form, an effect that is absent in CO adducts. The differing vibrational patterns of CO and NO adducts provide complementary information with respect to protein interactions, which may help to elucidate the mechanisms of ligand discrimination and signaling in heme sensor proteins.

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Section: Resultsmentioning

confidence: 91%

Differential Sensing of Protein Influences by NO and CO Vibrations in Heme Adducts

2006

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“…For example, when the heme of fungal NOR was substituted by a modified heme in which the heme had a variety of electron densities using a heme modification technique, it was found that the Fe-NO and N-O positions were essentially unchanged among the modified Fe 3ϩ -NO enzymes (37). In addition, it was also reported that the Fe-NO and N-O positions in Fe 3ϩ -NO porphyrin model compounds were insensitive to different substituents at the periphery of the porphyrin (38) and to variations in organic solvents with different polarities. 5 The vibrational spectral data of the Fe 3ϩ -NO complexes provided no information on the electronic structure of the Fe-NO coordination.…”

Section: No Coordination To Ferric Iron In Nor-mentioning

confidence: 99%

“…The Fe-CO frequency is reported to be a sensitive indicator of hydrophobicity around the Fe-CO moiety (40,41). For example, the Fe 2ϩ -CO complex of fungal NOR shows a Fe-CO at 487 cm Ϫ1 (18,38), while that of the camphor-bound form of P450cam appears at 484 cm Ϫ1 (42,43). The higher frequency shift of the Fe-CO in fungal NOR than in P450cam can be explained in terms of the more hydrophilic environment of the heme pocket.…”

Section: No Coordination To Ferric Iron In Nor-mentioning

confidence: 99%

Proton Delivery in NO Reduction by Fungal Nitric-oxide Reductase

Shimizu¹,

Obayashi²,

Gomi³

et al. 2000

Journal of Biological Chemistry

107

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Fungal nitric-oxide reductase (NOR) is a heme enzyme that catalyzes the reduction of NO to Nitric oxide (NO)1 serves as a messenger molecule for a variety of biological functions, including neurotransmission, vascular relaxation, and the inhibition of platelet aggregation. In mammalian systems, NO is generated from L-arginine and molecular oxygen (O 2 ), via catalysis by heme-enzyme nitricoxide synthase, whose crystal structure has recently been reported (1-3). Subsequently, the generated NO binds to the heme iron of soluble guanylate cyclase activating the conversion of GTP to cGMP. In addition, the crystal structures of the heme-based NO transport protein, nitrophorin, of a blood sucking insect were recently reported (4,5). NO is also a potential ligand (inhibitor) of many hemoproteins such as myoglobin, hemoglobin, and peroxidase (6 -8). Despite the close relation of NO to hemoproteins, only a small amount of structural information is available for NO adduct of hemoproteins. It is particularly noteworthy that much less is known concerning the ferric-NO (Fe 3ϩ -NO) complex of hemoproteins, and only one crystal structure of cytochrome c peroxidase by Poulos and co-workers (8, 9) and two of the ferric-porphyrin model compounds, Fe Fungal nitric oxide reductase (NOR), a heme enzyme, is involved in the denitrification process by the fungus Fusarium oxysporum (11). In this process, NO is produced from the reduction of NO 2 Ϫ catalyzed by nitrite reductase, which represents an additional NO generating biological system. In order to detoxify the generated NO, fungal NOR converts NO to N 2 O by the reaction (11),Based on spectroscopic and kinetic studies of this reaction, we proposed that the overall enzymatic reaction (Scheme 1) consists of three chemical reactions, Schemes 2-4 (12);

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“…Resonance Raman (RR) spectra have been extensively measured both for Fe(P)(NO) complexes and for nitrosylhemeproteins (Lipscomb et al, 1993;Spiro, 1983 and references therein).…”

Section: Ferrous Nitrosylheme With (Fenop Groupmentioning

confidence: 99%

“…The bands of the depolarized ring mode in the five-and sixcoordinated Fe(PPIXDME)(NO) complexes have been observed at 1643 cm-I and 1637 cm-I , respectively (Stong et aI., 1980). The Fe-NNo stretching (or bending) frequencies of six-coordinated nitrosyl heme have been measured in nitrosylhemeproteins (at around 550 cm-I ) such as NO-Hb, -Mb, and -HRP (Tsubaki and Yu, 1982;Benko and Yu, 1983), and in Fe(OEP)(NO)(NMelm) (at 524 cm-I ) (Lipscomb et al, 1993). The five-coordinated Fe(TPP)(NO) complex displayed the N-O and Fe-NNo stretching band at 1681 and 525 cm-I , respectively (Choi et al, 1991).…”

Section: Ferrous Nitrosylheme With (Fenop Groupmentioning

confidence: 99%

Nitric oxide, a versatile biological ligand for hemeproteies

Yoshimura¹

1995

Bioradicals Detected by ESR Spectroscopy

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Summary. In this article, the coordinating behavior of nitric oxide (NO) as a biological ligand for hemeproteins and enzymes is presented by reference to the spectral and stereochemical properties of nitrosylhemeproteins and their model nitrosylheme. The structural change in the heme coordination environments on NO binding to hemeproteins is described primarily in relation to the mechanisms of activation and inhibition of the enzymes by NO.

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Resonance Raman investigation of nitric oxide bonding in iron porphyrins: detection of the Fe-NO stretching vibration

Cited by 32 publications

References 0 publications

Differential Sensing of Protein Influences by NO and CO Vibrations in Heme Adducts

Differential Sensing of Protein Influences by NO and CO Vibrations in Heme Adducts

Proton Delivery in NO Reduction by Fungal Nitric-oxide Reductase

Nitric oxide, a versatile biological ligand for hemeproteies

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