Heme O Synthase and Heme A Synthase from Bacillus subtilis and Rhodobacter sphaeroides Interact in Escherichia coli

Brown, Brienne M.; Wang, Zhihong; Brown, Kenneth R.; Cricco, Julia A.; Hegg, Eric L.

doi:10.1021/bi048469k

Cited by 36 publications

(26 citation statements)

References 46 publications

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“…CtaA is observed in the anti-COX-N and anti-COX-D elution fractions, while Surf1c is observed in the antiCtaG and anti-COX-N fractions. CtaB and CtaA of Bacillus subtilis, as well as of R. sphaeroides (Cox10 and Cox15), have been shown to interact when heterologously expressed in E. coli [33], and our data support such an interaction in P. denitrificans as well. CtaB, which was observed in both the untreated and cross-linked samples, was selectively observed in elutions in which anti-CtaG and anti-COX-N were used as the bait antibodies.…”

Section: The Three Main Players In Cox Metallationsupporting

confidence: 73%

Deciphering protein–protein interactions during the biogenesis of cytochrome c oxidase from Paracoccus denitrificans

Gurumoorthy

Ludwig

2014

The FEBS Journal

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Biogenesis of the mitochondrial cytochrome c oxidase (COX) is a complex process due to its numerous subunits encoded by two genomes, as well as the localization of redox centers deep within the membrane. Here, we have assessed the biogenesis of the homologous aa 3 -type oxidase of the soil bacterium Paracoccus denitrificans. First, protein partners were analyzed using various membrane solubilization strategies to show interactions between COX and CtaG, a chaperone implicated in Cu B site metallation. Using an unbiased MS approach after immunological pull-down from untreated or cross-linked membranes, we then extend our view towards a hypothetical 'biogenesis complex' by identifying two further metal-inserting chaperones, Surf1c and Sco, together with enzymes catalyzing heme a synthesis. Our study also tentatively supports previous speculation regarding the existence of a predominantly co-translational mechanism for cofactor insertion during COX biogenesis.

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Section: The Three Main Players In Cox Metallationsupporting

confidence: 73%

Deciphering protein–protein interactions during the biogenesis of cytochrome c oxidase from Paracoccus denitrificans

Gurumoorthy

Ludwig

2014

The FEBS Journal

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“…Our previous data support a model whereby bacterial HOS and HAS interact to form a complex in which heme O is channeled directly from HOS to HAS (20). Because either the conversion of heme O to heme A or the release of the heme A product appears to be rate-limiting, we hypothesize that in bacteria this HAS-HOS complex might partially regulate the flux of hemes through the heme A biosynthetic pathway.…”

supporting

confidence: 76%

“…Previously it was generally believed that the transcription and translation of HOS and HAS are coordinated to obtain a 1:1 stoichiometry, because these two enzymes work cooperatively to synthesize heme A, and a HAS-HOS complex in bacteria is supported by our previous studies (20). There are three possible explanations concerning the 8:1 stoichiometry between HAS and HOS protein levels.…”

Section: Discussionmentioning

confidence: 63%

Regulation of the Heme A Biosynthetic Pathway

Wang

Hegg

2009

Journal of Biological Chemistry

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The assembly and activity of cytochrome c oxidase is dependent on the availability of heme A, one of its essential cofactors. In eukaryotes, two inner mitochondrial membrane proteins, heme O synthase (Cox10) and heme A synthase (Cox15), are required for heme A biosynthesis. In this report, we demonstrate that in Saccharomyces cerevisiae the transcription of COX15 is regulated by Hap1, a transcription factor whose activity is positively controlled by intracellular heme concentration. Conversely, COX10, the physiological partner of COX15, does not share the same regulatory mechanism with COX15. Interestingly, protein quantification identified an 8:1 protein ratio between Cox15 and Cox10. Together, these results suggest that heme A synthase and/or heme O synthase might play a new, unidentified role in addition to heme A biosynthesis.The biosynthesis of heme A, an obligatory cofactor of cytochrome c oxidase (CcO), 2 requires two nuclear-encoded proteins, heme O synthase (HOS) and heme A synthase (HAS) (1-5). Like CcO, both HOS and HAS are integral membrane proteins localized to the inner mitochondrial membrane. First, heme O synthase catalyzes the conversion of heme B to heme O via the farnesylation of a vinyl group at position C-2 (5). Second, heme A synthase converts heme O to heme A by oxidizing the C-8 methyl substituent on heme O to an aldehyde group (1, 2). Heme A has no known physiological function other than as a cofactor in the terminal heme-copper oxidases.COX10 and COX15, encoding eukaryotic HOS and HAS, respectively, are functionally conserved from yeast to humans (6, 7). In yeast, heme A deficiency leads to respiratory incompetence and the degradation of CcO (8). Mutations in either COX10 or COX15 in humans lead to metabolic diseases associated with isolated CcO deficiency, including Leigh syndrome and hypertrophic cardiomyopathy (9, 10). Recently, a deficiency in heme A biosynthesis was suggested to be involved in age-related decline of CcO in patients with Alzheimer disease (11).Assembly of the multisubunit CcO complex is a complicated and sequential process (12) that requires more than two dozen nuclear-encoded accessory proteins (13). The crystal structure of bovine heart CcO reveals that the two heme A molecules are deeply buried in the hydrophobic pocket of CcO (14), implying that the insertion of heme A probably occurs early during the CcO assembly process. The identification of a heme a-Cox1 intermediate and the lack of Cox1-Cox4-Cox5 subassembly complex in COX10-deficient human cells further support the notion that heme A insertion occurs at an early step during CcO assembly (12,15,16). In Rhodobacter sphaeroides, a deletion of Surf1 results in a 50% loss of heme a 3 , indicating that Surf1 might be involved in heme a 3 maturation (17).Because the availability of heme A is a key determinant in the assembly of CcO, the reactions catalyzed by HOS and HAS are likely targets for regulation. Because of its high reduction potential (18), free heme A is potentially even more toxic than free heme B. Th...

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“…Heme o is the substrate for this modification, which is catalyzed by a heme-containing monooxygenase (or peroxidase) enzyme called heme a synthase, encoded by the Bacillus ctaA and the related yeast COX11 genes (31,32,104,(149)(150)(151). In vivo, the heme o and a synthases may form a complex for substrate channeling (30). Note that E. coli has only cyoE, and thus one of its two terminal oxidases is a cytochrome bo copper oxidase, which is related to the more publicized cytochrome aa 3 copper oxidase (35,36,119).…”

Section: Heme Types and Modificationsmentioning

confidence: 99%

CytochromecBiogenesis: Mechanisms for Covalent Modifications and Trafficking of Heme and for Heme-Iron Redox Control

Kranz¹,

Richard-Fogal²,

Taylor

et al. 2009

Microbiol Mol Biol Rev

231

372

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SUMMARY Heme is the prosthetic group for cytochromes, which are directly involved in oxidation/reduction reactions inside and outside the cell. Many cytochromes contain heme with covalent additions at one or both vinyl groups. These include farnesylation at one vinyl in hemes o and a and thioether linkages to each vinyl in cytochrome c (at CXXCH of the protein). Here we review the mechanisms for these covalent attachments, with emphasis on the three unique cytochrome c assembly pathways called systems I, II, and III. All proteins in system I (called Ccm proteins) and system II (Ccs proteins) are integral membrane proteins. Recent biochemical analyses suggest mechanisms for heme channeling to the outside, heme-iron redox control, and attachment to the CXXCH. For system II, the CcsB and CcsA proteins form a cytochrome c synthetase complex which specifically channels heme to an external heme binding domain; in this conserved tryptophan-rich “WWD domain” (in CcsA), the heme is maintained in the reduced state by two external histidines and then ligated to the CXXCH motif. In system I, a two-step process is described. Step 1 is the CcmABCD-mediated synthesis and release of oxidized holoCcmE (heme in the Fe+3 state). We describe how external histidines in CcmC are involved in heme attachment to CcmE, and the chemical mechanism to form oxidized holoCcmE is discussed. Step 2 includes the CcmFH-mediated reduction (to Fe+2) of holoCcmE and ligation of the heme to CXXCH. The evolutionary and ecological advantages for each system are discussed with respect to iron limitation and oxidizing environments.

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Heme O Synthase and Heme A Synthase from Bacillus subtilis and Rhodobacter sphaeroides Interact in Escherichia coli

Cited by 36 publications

References 46 publications

Deciphering protein–protein interactions during the biogenesis of cytochrome c oxidase from Paracoccus denitrificans

Deciphering protein–protein interactions during the biogenesis of cytochrome c oxidase from Paracoccus denitrificans

Regulation of the Heme A Biosynthetic Pathway

CytochromecBiogenesis: Mechanisms for Covalent Modifications and Trafficking of Heme and for Heme-Iron Redox Control

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