Nucleotide sequence of the<i>guaB</i>locus encoding IMP dehydrogenaseof<i>Escherichia coli</i>K12

Tiedeman, A A; Smith, John L.

doi:10.1093/nar/13.4.1303

Cited by 51 publications

(24 citation statements)

References 57 publications

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“…In E. coli at least 13 de novo purine biosynthetic genes, including purK, have been mapped at nine different loci of the chromosome (1). To date, five genes, purF, purM, purN, guaA, and guaB, have been sequenced (27,28,31,32,34). Smith and Daum (27) reported the presence of a conserved sequence (33 of 39 base pairs) in the upstream region of purF (18) and purMN (27) (18) and Smith and Daum (27) there were highly conserved sequences at least 16 nucleotides in length (Fig.…”

Section: Resultsmentioning

confidence: 99%

Identification and sequence analysis of Escherichia coli purE and purK genes encoding 5'-phosphoribosyl-5-amino-4-imidazole carboxylase for de novo purine biosynthesis

et al. 1989

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It has been shown that the Escherichia coli purE locus specifying 5'-phosphoribosyl-5-amino-4-imidazole cairboxylase in de novo purine nucleotide synthesis is divided into two cistrons. We cloned and determined a 2,449-nucleotide sequence including the purl? locus. This sequence contains two overlapped open reading frames, ORF-18 and ORF-39, encoding proteins with molecular weights of 18,000 and 39,000, respectively. The purE mutations of CSH57A and DCSP22 were complemented by plasmids carrying ORF-18, while that of NK6051 was complemetited by plasmids carrying ORF-39. Thus, the purE locus consists of two distinct genes, designated purE and purK for ORF-18 and ORF-39, respectively. These genes constitute a single operon. A highly conserved 16-nucleotide sequence, termed the PUR box, was found in the upstream region of purE by comparing the sequences of the purF and purMN operons. We also found three entire and one partial repetitive extragenic palindromic (REP) sequences in the downstream region of purK. Roles of the PUR box and REP sequences are discussed in relation to the genesis of the purEK operon.5'-Phosphoribosyl-5-amino-4-imidazole (AIR) carboxylase (EC 4.1.1.21) catalyzes the conversion of AIR to carboxyl AIR in de novo purine biosynthesis (17). In Escherichia coli, AIR carboxylase is encoded by the purE locus, which is located at 12 min on the chromosome (1). Genetic studies showed that the purE locus was divided into two complementation groups, purEl and purE2 (8, 12). However, it is not clear whether these two cistrons specify two distinct polypeptides or two functional domains in a single polypeptide.Hamilton and Reeve (9, 10) determined the nucleotide sequences of DNA fragments from Methanobrevibacter smithii and Methanobacterium thermoautotrophicum that were able to complement both purEl and purE2 mutations of E. coli. These sequences encoded a single polypeptide chain whose structure appeared to arise from the fusion of tandemly duplicated polypeptide chains. They also reported that a small deletion that occurred in the 3' domain of the M. thermoautotrophicum gene did not complement either the purE) or the purE2 mutation (10). On the other hand, seqtence analysis of a 12-purine gene cluster from Bacillus subtilis showed that two distinct genes, purE and purK, were responsible for the activity of AIR carboxylase (5). These data suggest a considerable variation in organization of the genes and operons of AIR carboxylase from one organism to another.The E. coli DNA fragment that complements purEl and purE2 mutations has been cloned (13; J. M. Smith, cited in reference 5) and sequenced (J. M. Smith, cited in reference 5). However, the details of the sequencing have not been reported. To explore the organization of the E. coli purE locus, we also cloned independently the chromosomal fragment of this region and determined the nucleotide sequence.In this report, we demonstrate that the E. coli purE locus consists of two overlapped genes in a single operon. We * Corresponding author. t Publication of thi...

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Section: Resultsmentioning

confidence: 99%

Identification and sequence analysis of Escherichia coli purE and purK genes encoding 5'-phosphoribosyl-5-amino-4-imidazole carboxylase for de novo purine biosynthesis

et al. 1989

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“…IMPDH, encoded by the guaB gene catalyses the reversible conversion of IMP to XMP. In E. coli, at least two different enzymic pathways lead to the synthesis of XMP (Neuhard & Nygaard, 1996;Pimkin et al, 2009) which are well characterized (Gilbert et al, 1979;Gilbert & Drabble, 1980;Kerr & Hedstrom, 1997;Kerr et al, 2000;Tiedeman & Smith, 1985). However, the M. tuberculosis H37Rv purine de novo biosynthesis pathway enzymes have received little attention to date and are poorly studied.…”

Section: Discussionmentioning

confidence: 99%

“…The IMPDH reaction was first reported in 1957 in extracts of Aerobacter aerogenes (Magasanik et al, 1957). To date, IMPDH enzymes have been characterized from a variety of sources, which include humans (Carr et al, 1993;Hager et al, 1995;Hedstrom, 2009), protozoan parasites (Dobie et al, 2007) and bacteria (Ashbaugh & Wessels, 1995;Park et al, 2004;Tiedeman & Smith, 1985;Zhang et al, 2009). Many bacteria harbour a single gene for IMPDH, which is the sole provider of XMP for the cell and is thus vital for survival.…”

Section: Introductionmentioning

confidence: 99%

Identification of novel diphenyl urea inhibitors of Mt-GuaB2 active against Mycobacterium tuberculosis

et al. 2011

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In contrast with most bacteria, which harbour a single inosine monophosphate dehydrogenase (IMPDH) gene, the genomic sequence of Mycobacterium tuberculosis H37Rv predicts three genes encoding IMPDH: guaB1, guaB2 and guaB3. These three genes were cloned and expressed in Escherichia coli to evaluate functional IMPDH activity. Purified recombinant Mt-GuaB2, which uses inosine monophosphate as a substrate, was identified as the only active GuaB orthologue in M. tuberculosis and showed optimal activity at pH 8.5 and 37 6C. Mt-GuaB2 was inhibited significantly in vitro by a panel of diphenyl urea-based derivatives, which were also potent anti-mycobacterial agents against M. tuberculosis and Mycobacterium smegmatis, with MICs in the range of 0.2-0.5 mg ml "1 . When Mt-GuaB2 was overexpressed on a plasmid in trans in M. smegmatis, a diphenyl urea analogue showed a 16-fold increase in MIC. Interestingly, when Mt-GuaB orthologues (Mt-GuaB1 and 3) were also overexpressed on a plasmid in trans in M. smegmatis, they also conferred resistance, suggesting that although these Mt-GuaB orthologues were inactive in vitro, they presumably titrate the effect of the inhibitory properties of the active compounds in vivo.

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“…(1). The guaA and guaB sequences from B. burgdorferi, Bacillus subtilis (18,23), and E. coli (37,38) were aligned by using the MacVector Complementation. Plasmids pDH60 and pDH68 were derived from a library of B. burgdorferi B31 DNA partially digested with Tsp509I (New England Biolabs), cloned into vector XZAPII (Stratagene, La Jolla, Calif.), and screened with a guaA probe.…”

Section: Methodsmentioning

confidence: 99%

Plasmid location of Borrelia purine biosynthesis gene homologs

et al. 1994

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The Lyme disease spirochete Borrelia burgdorferi must survive in both its tick vector and its mammalian host to be maintained in nature. We have identified the B. burgdorferi guaA gene encoding GMP synthetase, an enzyme involved in de novo purine biosynthesis that is important for the survival of bacteria in mammalian blood. This gene encodes a functional product that will complement an Escherichia coli GMP synthetase mutant. The gene is located on a 26-kb circular plasmid, adjacent to and divergent from the gene encoding the outer surface protein C (OspC). The guaB gene homolog encoding IMP dehydrogenase, another enzyme in the purine biosynthetic pathway, is adjacent to guaA. In Borrelia hermsii, a tick-borne relapsing fever spirochete, the guaA and guaB genes are located on a linear plasmid. These are the first genes encoding proteins of known function to be mapped to a borrelial plasmid and the only example of genes encoding enzymes involved in the de novo purine biosynthesis pathway to be mapped to a plasmid in any organism. The unique plasmid location of these and perhaps other housekeeping genes may be a consequence of the segmented genomes in borreliae and reflect the need to adapt to both the arthropod and mammalian environments.

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Nucleotide sequence of theguaBlocus encoding IMP dehydrogenaseofEscherichia coliK12

Cited by 51 publications

References 57 publications

Identification and sequence analysis of Escherichia coli purE and purK genes encoding 5'-phosphoribosyl-5-amino-4-imidazole carboxylase for de novo purine biosynthesis

Identification and sequence analysis of Escherichia coli purE and purK genes encoding 5'-phosphoribosyl-5-amino-4-imidazole carboxylase for de novo purine biosynthesis

Identification of novel diphenyl urea inhibitors of Mt-GuaB2 active against Mycobacterium tuberculosis

Plasmid location of Borrelia purine biosynthesis gene homologs

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