A reappraisal of the diversity and class distribution of aspartate transcarbamoylases in Gram-negative bacteria

Kenny, Martin J.; McPhail, Donald R.; Shepherdson, Margaret

doi:10.1099/13500872-142-7-1873

Cited by 8 publications

(4 citation statements)

References 21 publications

(10 reference statements)

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“…A class A type of ATCase was also found in Paracoccus denitrificans, a species belonging to the ␣ subdivision of the proteobacteria (24). Furthermore, a 500-kDa ATCase was found in Deinococcus radiophilus (24), which on the basis of its 16S rRNA sequence, is phylogenetically remote from the proteobacteria while being closely related to Thermus sp. (63).…”

Section: Figmentioning

confidence: 96%

“…High-M r (450,000 to 500,000) proteins with ATCase activity and composed of polypeptides of around 34 and 45 kDa are widely distributed in the bacterial domain (24). This so-called class A type of ATCase has been encountered within the ␥ subdivision of the proteobacteria: in three fluorescent pseudomonads, in Azomonas agilis, and in Azotobacter vinelandii.…”

Section: Figmentioning

confidence: 99%

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Structure and expression of a pyrimidine gene cluster from the extreme thermophile Thermus strain ZO5

et al. 1997

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On a 4.7-kbp HindIII clone of Thermus strain ZO5 DNA, complementing an aspartate carbamoyltransferase mutation in Escherichia coli, we identified a cluster of four potential open reading frames corresponding to genes pyrR, and pyrB, an unidentified open reading frame named bbc, and gene pyrC. The transcription initiation site was mapped at about 115 nucleotides upstream of the pyrR translation start codon. The cognate Thermus pyr promoter also functions in heterologous expression of Thermus pyr genes in E. coli. In Thermus strain ZO5, pyrB and pyrC gene expression is repressed three-to fourfold by uracil and increased twofold by arginine. Based on the occurrence of several transcription signals in the Thermus pyr promoter region and strong amino acid sequence identities (about 60%) between Thermus PyrR and the PyrR attenuation proteins of two Bacillus sp., we propose a regulatory mechanism involving transcriptional attenuation to control pyr gene expression in Thermus. In contrast to pyr attenuation in Bacillus spp., however, control of the Thermus pyr gene cluster would not involve an antiterminator structure but would involve a translating ribosome for preventing formation of the terminator RNA hairpin. The deduced amino acid sequence of Thermus strain ZO5 aspartate carbamoyltransferase (ATCase; encoded by pyrB) exhibits the highest similarities (about 50% identical amino acids) with ATCases from Pseudomonas sp. For Thermus strain ZO5 dihydroorotase (DHOase; encoded by pyrC), the highest similarity scores (about 40% identity) were obtained with DHOases from B. caldolyticus and Bacillus subtilis. The enzyme properties of ATCase expressed from truncated versions of the Thermus pyr gene cluster in E. coli suggest that Thermus ATCase is stabilized by DHOase and that the translation product of bbc plays a role in feedback inhibition of the ATCase-DHOase complex.Thermus strain ZO5 is an extremely thermophilic gram-negative carotenoid pigmented bacterium which is closely related to Thermus aquaticus YT-1 and to T. thermophilus HB8 (10). The optimal growth temperature of Thermus strain ZO5 is about 72°C, and the maximum temperature for growth 85°C in rich medium. This microorganism has been studied with respect to antibiotic sensitivity, nutritional pattern, primary metabolism (10), and arginine biosynthesis (57).The metabolism of pyrimidines in extreme thermophiles deserves investigation from both fundamental and applied points of view. Genes of the pyrimidine biosynthetic pathway have been successfully used as genetic markers in mesophilic procaryotes and lower eucaryotes. Recently, the pyrE and pyrF genes from Thermus sp. were cloned and sequenced in order to provide selectable markers for developing thermophilic cloning vectors (61, 64). The T. thermophilus HB8 pyrH gene, encoding UMP kinase, was sequenced recently and shown to be located adjacent to the tsf gene, which codes for elongation factor Ts (4).De novo synthesis of pyrimidines involves utilization of energy-rich labile intermediates such as carbamoyl pho...

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Section: Figmentioning

confidence: 96%

Section: Figmentioning

confidence: 99%

Structure and expression of a pyrimidine gene cluster from the extreme thermophile Thermus strain ZO5

et al. 1997

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“…The ATCase from members of the genus Pseudomonas typifies Class A ATCases [14,20]. The P. fluorescens ATCase has been shown to consist of a 1:1 ratio of 34-kDa and 45-kDa polypeptides, which are arranged in a dodecamer [2].…”

mentioning

confidence: 99%

“…The Bacillus subtilis ATCase typifies the Class C enzyme, but several Gram-negative bacteria including Stenotrophomonas maltophilia also contain this size enzyme [14,15]. This 100-kDa enzyme is trimeric, consisting of three identical 33.5-kDa polypeptides [6], and does not interact with other enzymes of the pyrimidine pathway [22].…”

mentioning

confidence: 99%

Streptomyces Aspartate Transcarbamoylase Is a Dodecamer with Dihydroorotase Activity

Hughes

Hooshdaran

O’Donovan

1999

Current Microbiology

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Aspartate transcarbamoylase (ATCase) was purified from Streptomyces griseus. The enzyme is a dodecamer with a molecular mass of approximately 450 kDa. The holoenzyme is a complex of ATCase and active dihydroorotase (DHOase) subunits. The ATCase and DHOase activities co-purify after gel filtration and ion-exchange chromatography. Denaturing gel electrophoresis separates the holoenzyme into a 38-kDa ATCase polypeptide and a 47-kDa DHOase polypeptide. The holoenzyme retained ATCase and DHOase activity after being heated to 65 degrees C for 5 min, but after storage at 4 degrees C for 24 hours lost ATCase activity. Previously, the Pseudomonas putida Class A ATCase was defined by Schurr et al. (J Bacteriol 177, 1751-1759) as requiring an inactive DHOase to be functional. Here, we show that an active DHOase is part of the dodecameric ATCase/DHOase complex in Streptomyces. To distinguish those Class A ATCases with active DHOases from those with degenerate DHOases, we suggest the subdivision, Class A(1), for the former and Class A(2) for the latter.

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Aspartate Transcarbamoylase

Wales

Wilda²

2002

Encyclopedia of Molecular Biology

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A reappraisal of the diversity and class distribution of aspartate transcarbamoylases in Gram-negative bacteria

Cited by 8 publications

References 21 publications

Structure and expression of a pyrimidine gene cluster from the extreme thermophile Thermus strain ZO5

Structure and expression of a pyrimidine gene cluster from the extreme thermophile Thermus strain ZO5

Streptomyces Aspartate Transcarbamoylase Is a Dodecamer with Dihydroorotase Activity

Aspartate Transcarbamoylase

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