Structure of the heme o prosthetic group from the terminal quinol oxidase of Escherichia coli

Wu, Wenyuan; Chang, C. K.; Varotsis, Constantinos; Babcock, Gerald T.; Puustinen, Anne; Wikström, Mårten

doi:10.1021/ja00030a009

Cited by 79 publications

(37 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A peak at 556 nm correlated with the presence of mainly heme O bound to CtaA, and we therefore conclude that it is due to heme O. The observed 3-nm spectral difference between heme O and heme B bound to CtaA is congruent with the pyridine hemochrome spectrum of heme O, which is blue shifted 4 nm in comparison to that of heme B (33). The tight binding of heme O to the protein and the distinct spectra typical of lowspin cytochrome indicated that the overall structure of the mutant enzymes was not much disturbed compared to that of the wild-type protein.…”

Section: Vol 187 2005supporting

confidence: 62%

Heme A Synthase Enzyme Functions Dissected by Mutagenesis ofBacillus subtilisCtaA

2005

View full text Add to dashboard Cite

Heme A, as a prosthetic group, is found exclusively in respiratory oxidases of mitochondria and aerobic bacteria. Bacillus subtilis CtaA and other heme A synthases catalyze the conversion of a methyl side group on heme O into a formyl group. The catalytic mechanism of heme A synthase is not understood, and little is known about the composition and structure of the enzyme. In this work, we have: (i) constructed a ctaA deletion mutant and a system for overproduction of mutant variants of the CtaA protein in B. subtilis, (ii) developed an affinity purification procedure for isolation of preparative amounts of CtaA, and (iii) investigated the functional roles of four invariant histidine residues in heme A synthase by in vivo and in vitro analyses of the properties of mutant variants of CtaA. Our results show an important function of three histidine residues for heme A synthase activity. Several of the purified mutant enzyme proteins contained tightly bound heme O. One variant also contained trapped hydroxylated heme O, which is a postulated enzyme reaction intermediate. The findings indicate functional roles for the invariant histidine residues and provide strong evidence that the heme A synthase enzyme reaction includes two consecutive monooxygenations.

show abstract

Section: Vol 187 2005supporting

confidence: 62%

Heme A Synthase Enzyme Functions Dissected by Mutagenesis ofBacillus subtilisCtaA

2005

View full text Add to dashboard Cite

show abstract

“…This can account for the appearance of the Fe(V)ϭO at 804 cm Ϫ1 and the Fe(IV)ϭO at 790 cm Ϫ1 . The observation of the 805 cm Ϫ1 mode in the cytochrome bo 3 /H 2 O 2 reaction (60), however, argues against this possibility since the heme O lacks a strong electron-withdrawing peripheral substituent (61). On the other hand, the occurrence of Cu 3ϩ has been demonstrated in model compounds, but supporting evidence in Cu-containing enzymes has not been reported so far (62,63).…”

Section: Discussionmentioning

confidence: 81%

Direct Detection of Fe(IV)=O Intermediates in the Cytochrome aa3 Oxidase from Paracoccus denitrificans/H2O2 Reaction

Pinakoulaki

Pfitzner

Ludwig

et al. 2003

Journal of Biological Chemistry

View full text Add to dashboard Cite

We report the first evidence for the formation of the "607-and 580-nm forms" in the cytochrome oxidase aa 3 / H 2 O 2 reaction without the involvement of tyrosine 280. The pK a of the 607-580-nm transition is 7.5. The 607-nm form is also formed in the mixed valence cytochrome oxidase/O 2 reaction in the absence of tyrosine 280. Steady-state resonance Raman characterization of the reaction products of both the wild-type and Y280H cytochrome aa 3 from Paracoccus denitrificans indicate the formation of six-coordinate low spin species, and do not support, in contrast to previous reports, the formation of a porphyrin -cation radical. We observe three oxygen isotope-sensitive Raman bands in the oxidized wildtype aa 3 /H 2 O 2 reaction at 804, 790, and 358 cm ؊1 . The former two are assigned to the Fe(IV)‫؍‬O stretching mode of the 607-and 580-nm forms, respectively. The 14 cm ؊1 frequency difference between the oxoferryl species is attributed to variations in the basicity of the proximal to heme a 3 His-411, induced by the oxoferryl conformations of the heme a 3 -Cu B pocket during the 607-580-nm transition. We suggest that the 804 -790 cm ؊1 oxoferryl transition triggers distal conformational changes that are subsequently communicated to the proximal His-411 heme a 3 site. The 358 cm ؊1 mode has been found for the first time to accumulate with the 804 cm ؊1 mode in the peroxide reaction. These results indicate that the mechanism of oxygen reduction must be reexamined.

show abstract

“…Hemes O and A are derivatives of protoheme IX (heme B) in which the vinyl group at pyrrole ring A is substituted by a 17-carbon hydroxyethylfarnesyl group, in addition, heme A contains a formyl group in place of the methyl group at pyrrole ring D [1] (for a review see [2][3][4]). The farnesylated hemes and their variants are found exclusively in the heme-copper respiratory oxidases [1], and seem essential for the catalytic functions of the binuclear center [5][6][7], except for a newly found subfamily, cbb3-type cytochrome c oxidase [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

An Escherichia coli cyoE gene homologue in thermophilic Bacillus PS3 encodes a thermotolerant heme O synthase

Saiki¹,

Mogi²,

Ishizuka³

et al. 1994

FEBS Letters

View full text Add to dashboard Cite

The cyoE gene of the Escherichia coli bo-type quinol oxidase operon (cyoABCDE) has been previously shown to encode heme O synthase. To demonstrate a catalytic role of a cyoE homologue (the caaE gene) in the gene cluster for caa3-type cytochrome c oxidase of thermophilic Bacillus PS3, we have carried out genetic complementation analysis using the chimeric operon cyoABCD-caaE and heme O synthase assay using the CaaE-overproduced E. coli membranes. We found that the caaE gene encodes a thermotolerant heine O synthase which provides an intermediate for heme A biosynthesis.

show abstract

Structure of the heme o prosthetic group from the terminal quinol oxidase of Escherichia coli

Cited by 79 publications

References 3 publications

Heme A Synthase Enzyme Functions Dissected by Mutagenesis ofBacillus subtilisCtaA

Heme A Synthase Enzyme Functions Dissected by Mutagenesis ofBacillus subtilisCtaA

Direct Detection of Fe(IV)=O Intermediates in the Cytochrome aa3 Oxidase from Paracoccus denitrificans/H2O2 Reaction

An Escherichia coli cyoE gene homologue in thermophilic Bacillus PS3 encodes a thermotolerant heme O synthase

Contact Info

Product

Resources

About