Identification of Lys79 as an iron ligand in one form of alkaline yeast iso-1-ferricytochrome c

Ferrer, Juan C.; Guillemette, J. Guy; Bogumil, Ralf; Inglis, Stephen; Smith, Michael B.; Mauk, A. Grant

doi:10.1021/ja00069a062

Cited by 136 publications

(139 citation statements)

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“…The spectroscopic results presented here for the cytochrome [24], cytochrome f (His/N-terminal amine) [25], and the butylb560 of bovine SQR complement those obtained previously for amine adduct ofleghemoglobin [19]. Alkaline cytochrome c has the cytochrome b components of B. subtilis and E. coli SQR 2cx = 1480 nm with Ae = 420 M -~ "cm -I (4.2 K and 5 T) [26], [16,17].…”

Section: K and 5 T) In Sqr And Is Broadened And Shifted To 1535supporting

confidence: 81%

Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Crouse¹,

Yu²,

Johnson³

1995

FEBS Letters

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13 kDa), but are devoid of a b-type cytochrome [7]. The QPs Abstract The axial ligands of low potential cytochrome b560 in in SQRs from bovine heart mitochondria [8,9] and E. coli the five subunit bovine heart succinate-ubiquinone reductase com- [10,11] both contain one cytochrome b, but differ in the number plex and in the isolated quinone binding proteins have been invesand size of the constituent subunits (14-, 11-and 9-kDa subtigated using EPR and near-infrared magnetic circular dichroism spectroscopies. The results are consistent with bis-histidine ligaunits for bovine heart QPs [3,4]; 14-and 13-kDa subunits for tion with near-perpendicular imidazole rings for cytochrome b56oE. coli QPs [12,13]). Moreover, the cytochrome bs in these in the four-subunit complex. The pronounced changes in EPR enzymes differ greatly in their midpoint potentials; E m = +36 properties that accompany isolation of the cytochrome-b560 conmV and -180 mV for E. coli and bovine heart SQR, However, this was before the presence of distinct low and high Bovine heart succinate-quinone reductase (SQR) is a mempotential hemes was established in B. subtilis cytochrome b558 brane-bound component of the mitochondrial respiratory [14]. Therefore, although these results taken together attest to chain. It catalyzes the oxidation of succinate to fumarate and bis-histidyl ligation for the high potential cytochrome bs (charthe reduction of ubiquinone, thereby contributing electrons acterized by HALS EPR signals with ramped line shapes for ultimately to oxidative phosphorylation and energy transducthe low-field component), the axial ligation of the low potential tion. The purified complex can be resolved into two reconstitucytochrome bs remains ill-defined. The low potential cytotively active fractions [1,2]. One fraction, composed of the two chrome b560 of bovine heart SQR exhibits a HALS-type EPR larger subunits (70 and 27 kDa), is the soluble succinate dehysignal with a Gaussian-shaped low-field component at g = 3.46, drogenase (SDH) which contains a flavin moiety as well as but this resonance is replaced by two new resonances with low three Fe-S clusters. The other fraction, termed the quinone field g-values at 3.07 and 2.92 in purified QPs [8]. In this work, binding proteins (QPs), anchors SDH to the mitochondrial the two complementary techniques of EPR and MCD have inner membrane and comprises three smaller subunits (14, 11, been used to investigate the axial ligation of the low potential and 9 kDa) [3,4]. This membrane-bound fraction contains the cytochrome b560 in bovine heart SQR and the isolated QPs. cytochrome b560 that is the focus of this paper [5,6].As their name suggests, the QPs facilitate interaction of 2. Materials and methods SDHs and the highly homologous fumarate reductases (FRDs) with quinones. However, a specific role for the heme group in Bovine heart SQR and QPs were purified and assayed as previously mediating electron transfer to or from quinone has yet to be described [8]. Samples for spectroscopic measurements were prepar...

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Section: K and 5 T) In Sqr And Is Broadened And Shifted To 1535supporting

confidence: 81%

Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Crouse¹,

Yu²,

Johnson³

1995

FEBS Letters

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“…As already reported, spectra recorded at different pH values evidenced the transition from the native low spin form (III) at neutral pH to the alkaline low spin form (IV) (Fig. 4B) (13,18,19,24). Several resonances change at high pH (such as those from methyl groups 3, 5, and 8) revealing an overall perturbation of the heme environment.…”

supporting

confidence: 75%

“…The transformation of the state III species (referred to the "neutral" species from now on) into state IV species (the "alkaline" species) upon pH increase is called the alkaline transition (which occurs with a pK a of ϳ9.3) (13, 18 -24). This conformational change is present in all known isoforms of type c cytochrome and implies the displacement of Met-80 from the heme and its substitution by another ligand, Lys-72 or Lys-79 (13,18,24,25), keeping the iron in a low spin state.…”

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confidence: 99%

Nitration of Solvent-exposed Tyrosine 74 on Cytochrome c Triggers Heme Iron-Methionine 80 Bond Disruption

Abriata

Cassina

Tortora

et al. 2009

Journal of Biological Chemistry

135

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Cytochrome c, a mitochondrial electron transfer protein containing a hexacoordinated heme, is involved in other physiologically relevant events, such as the triggering of apoptosis, and the activation of a peroxidatic activity. The latter occurs secondary to interactions with cardiolipin and/or post-translational modifications, including tyrosine nitration by peroxynitrite and other nitric oxide-derived oxidants. The gain of peroxidatic activity in nitrated cytochrome c has been related to a heme site transition in the physiological pH region, which normally occurs at alkaline pH in the native protein. Herein, we report a spectroscopic characterization of two nitrated variants of horse heart cytochrome c by using optical spectroscopy studies and NMR. Highly pure nitrated cytochrome c species modified at solvent-exposed Tyr-74 or Tyr-97 were generated after treatment with a flux of peroxynitrite, separated, purified by preparative high pressure liquid chromatography, and characterized by mass spectrometry-based peptide mapping. It is shown that nitration of Tyr-74 elicits an early alkaline transition with a pK a ‫؍‬ 7.2, resulting in the displacement of the sixth and axial iron ligand Met-80 and replacement by a weaker Lys ligand to yield an alternative low spin conformation. Based on the study of site-specific Tyr to Phe mutants in the four conserved Tyr residues, we also show that this transition is not due to deprotonation of nitro-Tyr-74, but instead we propose a destabilizing steric effect of the nitro group in the mobile ⍀-loop of cytochrome c, which is transmitted to the iron center via the nearby Tyr-67. The key role of Tyr-67 in promoting the transition through interactions with Met-80 was further substantiated in the Y67F mutant. These results therefore provide new insights into how a remote post-translational modification in cytochrome c such as tyrosine nitration triggers profound structural changes in the heme ligation and microenvironment and impacts in protein function.

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“…The good agreement between the results of the empirical and the molecular orbital methods shows that the parameterisation of the empirical equation [15] for haem methyl groups can also be used for the cases of oxidised haems with His^CN 3 and His^Lys co-ordination, provided that data can be obtained at 298 K. In this way, it was possible to use the published 1 H NMR data available in the literature [1] to calculate the value The 1 H shifts measured at 298 K, reported in Table 1, were ¢tted to the empirical Eq. 1 [15].…”

Section: Discussionmentioning

confidence: 94%

“…where the sign for the ¢nal correction is negative for 2 1 and 7 1 CH 3 and positive for 12 1 and 18 1 CH 3 . The angle a i is that between the vector connecting the ring methyl group i to the iron and the NC^NA vector.…”

Section: Methodsmentioning

confidence: 99%

Replacement of the methionine axial ligand in cytochrome c₅₅₀ by a lysine: effects on the haem electronic structure

Louro¹,

Waal²,

Ubbink³

et al. 2001

FEBS Letters

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The prosthetic group of low-spin haem proteins is an iron porphyrin with two axial ligands, typically histidine, methionine or lysine. Determining the geometry of the axial ligands is an important step in structural characterisation, particularly in the paramagnetic oxidised forms. This work extends earlier studies of the hyperfine nuclear magnetic resonance (NMR) shifts of haem substituents in bis-His and His^Met cytochromes to His^Lys co-ordination in the M100K mutant of Paracoccus versutus cytochrome c 550 . The electronic structure of the His^Lys haem is shown to be similar to that produced by His^cyanide co-ordination, such that NMR can be used to determine the geometry of the His ligand. ß

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Identification of Lys79 as an iron ligand in one form of alkaline yeast iso-1-ferricytochrome c

Cited by 136 publications

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Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Nitration of Solvent-exposed Tyrosine 74 on Cytochrome c Triggers Heme Iron-Methionine 80 Bond Disruption

Replacement of the methionine axial ligand in cytochrome c₅₅₀ by a lysine: effects on the haem electronic structure

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Identification of Lys79 as an iron ligand in one form of alkaline yeast iso-1-ferricytochrome c

Cited by 136 publications

References 0 publications

Spectroscopic identification of the axial ligands of cytochrome b560 in bovine heart succinate‐ubiquinone reductase

Spectroscopic identification of the axial ligands of cytochrome b560 in bovine heart succinate‐ubiquinone reductase

Nitration of Solvent-exposed Tyrosine 74 on Cytochrome c Triggers Heme Iron-Methionine 80 Bond Disruption

Replacement of the methionine axial ligand in cytochrome c550 by a lysine: effects on the haem electronic structure

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Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Replacement of the methionine axial ligand in cytochrome c₅₅₀ by a lysine: effects on the haem electronic structure