Characterization of a molybdenum cofactor biosynthetic gene cluster in Rhodobacter capsulatus which is specific for the biogenesis of dimethylsulfoxide reductase

Solomon, Peter S.; Shaw, Anthony; Lane, Ian C.; Hanson, Graeme R.; Palmer, Tracy; McEwan, Alastair G.

doi:10.1099/13500872-145-6-1421

Cited by 18 publications

(13 citation statements)

References 45 publications

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“…Indeed we observed weak (Ͻ0.01 spin/MOCS1A monomer), isotropic g ϭ 2.01 resonances at 70 K with relaxation properties indicative of a radical species in both the aerobically and anaerobically purified samples of MOCS1A investigated in this work (data not shown). His-tagged Rhodobacter capsulatus MoaA was heterologously expressed as inclusion bodies in E. coli, and evidence for the presence of a [3Fe-4S] ϩ cluster was based on the presence of a fast relaxing S ϭ 1/2 resonance (g ϭ 2.023, 2.015, and 2.004) of unknown concentration in the 2 K EPR spectrum of the washed insoluble pellet (31).…”

Section: Discussionmentioning

confidence: 99%

“…MOCS1A and orthologous MoaA proteins in eukaryotes and prokaryotes were characterized as FeS cluster-containing proteins (15,31). The de novo synthesis and assembly of FeS clusters in E. coli is mediated by the ISC (iron-sulfur cluster) system (iscRSUA-hscBA-fdx) (32), while the SUF (sulfur) system (sufABCDSE) (33) has been proposed to be involved in the repair of oxidatively damaged FeS clusters and/or play a role in FeS biosynthesis under conditions of iron limitation (34).…”

Section: Effect Of Isc and Suf Proteins As Well As The Groes/el Chapementioning

confidence: 99%

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Characterization of MOCS1A, an Oxygen-sensitive Iron-Sulfur Protein Involved in Human Molybdenum Cofactor Biosynthesis

Hänzelmann

Hernandez

Menzel

et al. 2004

Journal of Biological Chemistry

139

124

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The human proteins MOCS1A and MOCS1B catalyze the conversion of a guanosine derivative to precursor Z during molybdenum cofactor biosynthesis. MOCS1A shares homology with S-adenosylmethionine (AdoMet)-dependent radical enzymes, which catalyze the formation of protein and/or substrate radicals by reductive cleavage of AdoMet through a [4Fe-4S] cluster. Sequence analysis of MOCS1A showed two highly conserved cysteine motifs, one near the N terminus and one near the C terminus. MOCS1A was heterologously expressed in Escherichia coli and purified under aerobic and anaerobic conditions. Individual mutations of the conserved cysteines to serine revealed that all are essential for synthesis of precursor Z in vivo. The molybdenum cofactor in eukaryotic molybdoenzymes consists of a mononuclear molybdenum coordinated by the dithiolene moiety of a tricyclic pyranopterin, termed molybdopterin (MPT) 1 (1). In humans, defects in molybdenum cofactor biosynthesis lead to the pleiotropic loss of the molybdoenzymes sulfite oxidase, aldehyde oxidase, and xanthine dehydrogenase (2, 3). Affected patients usually die shortly after birth and show neurological abnormalities, such as attenuated growth of the brain, untreatable seizures, and dislocated ocular lenses (4). The first step during human molybdenum cofactor biosynthesis is catalyzed by MOCS1A and MOCS1B, leading to the synthesis of precursor Z, an oxygen-sensitive 6-alkyl pterin with a cyclic phosphate, from a guanosine derivative, most likely 5Ј-GTP (5-7).Analogous to other pteridine biosynthetic pathways, synthesis of precursor Z has been proposed to occur via a GTP cyclohydrolase-like reaction mechanism (5, 6). In contrast to these pathways, the C-8 atom of 5Ј-GTP is not released as formate but is retained and incorporated in a rearrangement reaction as the first carbon atom of the precursor Z side chain. In the second step of molybdenum cofactor biosynthesis catalyzed by MOCS3 (8) and MPT synthase (MOCS2) precursor Z is converted into MPT (9 -11). Finally molybdenum is incorporated into MPT by the multifunctional protein gephyrin (12, 13).MOCS1A contains two highly conserved cysteine motifs ( Fig. 1) proposed to be involved in iron-sulfur (FeS) cluster binding (14, 15), one is located near the N terminus (consensus sequence CX 3 CX 2 C where X denotes any amino acid), and one is near the C terminus (consensus sequence CX 2 CX 13 C). Several mutations identified in molybdenum cofactor deficiency patients are located in these conserved cysteine motifs indicating their functional importance for protein activity (2, 3). Based on sequence similarities to proteins such as biotin synthase, pyruvate formate-lyase-activating enzyme, and anaerobic ribonucleotide reductase-activating enzyme, MOCS1A has been classified as a member of the superfamily of S-adenosylmethionine (AdoMet)-dependent radical enzymes (16). In this class of enzymes, AdoMet serves as the free radical initiator and undergoes cleavage to methionine and a 5Ј-deoxyadenosyl radical that in turn propagates radical for...

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Section: Discussionmentioning

confidence: 99%

Section: Effect Of Isc and Suf Proteins As Well As The Groes/el Chapementioning

confidence: 99%

Characterization of MOCS1A, an Oxygen-sensitive Iron-Sulfur Protein Involved in Human Molybdenum Cofactor Biosynthesis

Hänzelmann

Hernandez

Menzel

et al. 2004

Journal of Biological Chemistry

139

124

View full text Add to dashboard Cite

show abstract

“…These are thought to be the locations of Fe-S centers that serve as the active sites in reactions involving hydration or dehydration of substrate compounds (38,45). MoaA catalyzes a step of molybdenum cofactor synthesis in which precursor Z is produced from the phosphorylated guanosine precursor prior to MoeB-dependent sulfur addition (30,45).…”

Section: Discussionmentioning

confidence: 99%

Mutational Analysis of the sbo-alb Locus of Bacillus subtilis : Identification of Genes Required for Subtilosin Production and Immunity

2000

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The Bacillus subtilis 168 derivative JH642 produces a bacteriocin, subtilosin, which possesses activity against Listeria monocytogenes. Inspection of the amino acid sequence of the presubtilosin polypeptide encoded by the gene sboA and sequence data from analysis of mature subtilosin indicate that the precursor subtilosin peptide undergoes several unique and unusual chemical modifications during its maturation process. The genes of the sbo-alb operon are believed to function in the synthesis and maturation of subtilosin. Nonpolar mutations introduced into each of the alb genes resulted in loss or reduction of subtilosin production. sboA, albA, and albF mutants showed no antilisterial activity, indicating that the products of these genes are critical for the production of active subtilosin. Mutations in albB, -C, and -D resulted in reduction of antilisterial activity and decreased immunity to subtilosin, particularly under anaerobic conditions. A new gene, sboX, encoding another bacteriocin-like product was discovered residing in a sequence overlapping the coding region of sboA. Construction of an sboX-lacZ translational fusion and analysis of its expression indicate that sboX is induced in stationary phase of anaerobic cultures of JH642. An in-frame deletion of the sboX coding sequence did not affect the antilisterial activity or production of or immunity to subtilosin. The results of this investigation show that the sbo-alb genes are required for the mechanisms of subtilosin synthesis and immunity.

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“…1). dorB is located between dorA and a gene cluster encoding enzymes involved in Moco biosynthesis (Solomon et al, 1999).…”

Section: Nucleotide Sequence and Organization Of The Dor Operonmentioning

confidence: 99%

Mutational analysis of the dimethylsulfoxide respiratory (dor) operon of Rhodobacter capsulatus

et al. 1999

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Four genes, dorC, dorD, dorB and dorR of the DMSO respiratory gene cluster of Rhodobacter capsulatus have been identified and sequenced. dorC encodes a pentahaem c-type cytochrome of the NirT class and the derived DorC protein sequence shows highest similarity to TorC from the Escherichia coli trimethylamine-N-oxide (TMAO) respiratory system. Mutagenesis of dorC resulted in the loss of a 46 kDa haem-staining polypeptide from membranes of R. capsulatus. dorD encodes a protein with highest sequence similarity to TorD from the E. coli TMAO respiratory system. DMSO reductase polypeptide (DorA) could not be detected in cell-free extracts of a dorD mutant and it is suggested that DorD has a role in stabilizing the DorA apo-protein prior to insertion of the pterin molybdenum cofactor. dorB encodes a protein with highest sequence similarity to NapD of Paracoccus denitrificans. Mutagenesis of dorB reduced the activity of DMSO reductase and led to the accumulation of a larger form of the enzyme that is presumed to represent a cytoplasmic precursor polypeptide. It is suggested that DorB has a role in the biogenesis of DMSO reductase prior to its secretion into the periplasm. dorR is transcribed in the opposite direction to dorC. The derived amino acid sequence of DorR indicates that it is a response regulator and mutation of dorR shows that it is essential for expression of the dorCDA operon. Expression of a chromosomal dorA::lacZ fusion was also dependent on the transcriptional regulator Fnr. The intergenic region between dorR and dorC contains four putative binding sites for DorR but no binding site for Fnr was identified.

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Characterization of a molybdenum cofactor biosynthetic gene cluster in Rhodobacter capsulatus which is specific for the biogenesis of dimethylsulfoxide reductase

Cited by 18 publications

References 45 publications

Characterization of MOCS1A, an Oxygen-sensitive Iron-Sulfur Protein Involved in Human Molybdenum Cofactor Biosynthesis

Characterization of MOCS1A, an Oxygen-sensitive Iron-Sulfur Protein Involved in Human Molybdenum Cofactor Biosynthesis

Mutational Analysis of the sbo-alb Locus of Bacillus subtilis : Identification of Genes Required for Subtilosin Production and Immunity

Mutational analysis of the dimethylsulfoxide respiratory (dor) operon of Rhodobacter capsulatus

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