Identification of <i>glyA</i> as a symbiotically essential gene in <i>Bradyrhizobium japonicum</i>

Rossbach, Silvia; Hennecke, Hauke

doi:10.1111/j.1365-2958.1991.tb01824.x

Cited by 39 publications

(38 citation statements)

References 35 publications

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“…The S. meliloti chromosomal copy of glyA is most likely involved in glycine biosynthesis. The presence of two copies of glyA is interesting, because a glyA mutant of B. japonicum forms nonfixing nodules (56). The authors of that study proposed that the fixation phenotype resulted from an inability to synthesize glycine, yet the mutant was only a leaky auxotroph for glycine.…”

Section: Correlation Of Carbon Utilization Phenotypes With Psyma Sequmentioning

confidence: 99%

Nucleotide sequence and predicted functions of the entire Sinorhizobium meliloti pSymA megaplasmid

Barnett

Fisher

Jones

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

281

227

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The symbiotic nitrogen-fixing soil bacterium Sinorhizobium meliloti contains three replicons: pSymA, pSymB, and the chromosome. We report here the complete 1,354,226-nt sequence of pSymA. In addition to a large fraction of the genes known to be specifically involved in symbiosis, pSymA contains genes likely to be involved in nitrogen and carbon metabolism, transport, stress, and resistance responses, and other functions that give S. meliloti an advantage in its specialized niche.

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Section: Correlation Of Carbon Utilization Phenotypes With Psyma Sequmentioning

confidence: 99%

Nucleotide sequence and predicted functions of the entire Sinorhizobium meliloti pSymA megaplasmid

Barnett

Fisher

Jones

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

281

227

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“…Mutants of E. coli, S. typhimurium, and B. japonicum defective in glyA are known to be glycine auxotrophs (28,35). A mutant of M. extorquens AM1, G82, which was induced by chemical mutagenesis that required glycine for growth on succinate and lacked SHMT activity when grown on this substrate, was described earlier (13 The activity of SHMT was determined in cell extracts of two glyA mutants, Glyl and Glyl6, and the wild-type M. extorquens AM1 was grown on succinate and induced with methanol.…”

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confidence: 99%

“…2), and the sequence of this fragment was determined, revealing the presence of an open reading frame with similarity to glyA genes from H. methylovorum GM2 (24), Bradyrhizobium japonicum (28), Salmonella typhimunium (36), E. coli (27), Campylobacter jejuni (3), Neurospora crassa (22), and rabbits (20,21). The complete sequence of glyA from M. extorquens AM1 was obtained (data not shown), consisting of 1,305 nucleotides, including the stop codon, which were able to encode a polypeptide with a molecular mass of 46,305 Da, and it was found to contain the conserved sequence (GGHLTHG) used to design the oligonucleotide probe.…”

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confidence: 99%

Genetics of the serine cycle in Methylobacterium extorquens AM1: cloning, sequence, mutation, and physiological effect of glyA, the gene for serine hydroxymethyltransferase

Chistoserdova

Lidstrom

1994

J Bacteriol

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The gene (glyA) ofMethylobacterium extorquens AM1 encoding serine hydroxymethyltransferase (SHMT), one of the key enzymes of the serine cycle for C1 assimilation, was isolated by using a synthetic oligonucleotide with a sequence based on amino acid sequence conserved in SHMTs from different sources. The amino acid sequence deduced from the gene revealed high similarity to those of known SHMTs. The cloned gene was inactivated by insertion of a kanamycin resistance gene, and recombination of this insertion derivative with the wild-type gene produced an SHMT null mutant. Surprisingly, this mutant had lost its ability to grow on C1 as well as on C2 compounds but was still able to grow on succinate. The DNA fragment containing glyA was shown not to be linked with fragments carrying serine cycle genes identified earlier, making it the fourth chromosomal region of M. extorquens AMI to be indicated as being involved in C1 assimilation.Methylobacterium extorquens AM1 is a pink-pigmented serine cycle methylotroph able to grow on methanol and methylamine as well as on a variety of multicarbon substrates (26,34). This organism has been successfully used as a model for genetic studies of methanol and methylamine oxidation (14,17,18). Recently, progress has also been achieved in studying the genetics of the serine cycle in this strain, with three regions coding for serine cycle enzymes having been identified. One of these regions has been shown to encode genes for serine glyoxylate aminotransferase (sgaA), hydroxypyruvate reductase (hprA), methylenetetrahydrofolate dehydrogenase (mtdA4 [7]), malate thiokinase (mtkA and mtkB [8]), phosphoenolpyruvate carboxylase (ppcA [2]), and malyl coenzyme (CoA)-lyase (mcA [12]). Mutations in all of these genes have been obtained to confirm that they are required for the operation of the serine cycle (2, 6-8). Two other regions of the M. extorquens AM1 chromosome that contain serine cycle genes have been less extensively studied. One of these complements glycerate kinase mutants, and another complements mutants with lesion(s) in the unknown acetyl-CoA oxidation pathway portion of the serine cycle (33). Neither of these fragments overlaps the region containing sgaA, hprA, mtdA, mtkAB, ppcA, and mcL4 (7). The gene (glyA) for another serine cycle enzyme, serine hydroxymethyltransferase (SHMT), has been recently cloned and sequenced from an obligate methylotroph, Hyphomicrobium methylovorum GM2 (24); however, its location relative to other methylotrophy genes in that bacterium is unknown.We were interested in cloning glyA from M. extorquens AM1 in order to clarify its role in this organism. It has been suggested that during growth of M. extorquens AM1 on succinate and other multicarbon compounds, the serine necessary for cell biosynthesis is produced by the phosphorylated pathway (15). During growth on C1 compounds, the phosphorylated pathway plays a minor role, since the serine cycle is the major source of serine under these growth conditions (Fig. 1) (1, 13) 395-2940. glycine from serine...

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“…____-_________-_______ MS~LEMFDKEIFDLTNKElEPQCEClEMlASE~FTlPEVHEVMCSllTMKVAEGVPCKRVVCCCEFVDElETlAlERCKKlFNCK---FA-NV9PNSC (3) ----------------------HNVlPQQDP~VFAAlEQEEK~QHAKlELlASENFVSRAVHEAQCSVlTNKVAEGVPCPRVVCCCEVVDlVEElARE~AKQlFCAE---HA-NVQPHSC ( 4 ) -------MTSAKTASAPDSFFTAS-lD9ADPElAAAlKGElGE9PHEVEllASENlVSRAVlEA9CSVHTNKVAECVPCAlVVCCCEWVDVAENlAlDRAKKlFCAG---FA-NVQPNSG (5) -----------------MLKPEMN-lADVDAElWQAHE9EKVR9EEHlELlASENYlSP~VMQA9CSQlTNKVAECVPGKRVVCCCEVVDlVE9LAlDEAKElFCAD---VA-NVQPHSC (6) -----------------HlK~EMN-lADVDAElWQAHE9EKV~9EEHlEllASENVTSPRVH9A9CSQlTNKVAECYPCKPVVGCC~VVDVVE9lAlDRAKElFCAD-- [2]; B. stearothermophilus, [3]; C. jejuni, [4]; B. japonicum, [ 5 ] ; rabbit mt., [6]; rabbit cyt., [7].…”

Section: ~~~~~Hssapaagtastspffksh-vs~tdpdlf~al9kefcp9qhelellasenlvs9amentioning

confidence: 99%

Molecular cloning and expression of the gene for serine hydroxymethyltransferase from an obligate methylotroph Hyphomicrobium methylovorum GM2

Miyata

Yoshida

Yamagata

et al. 1993

European Journal of Biochemistry

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The gene encoding serine hydroxymethyltransferase (SHMT), one of the key enzymes of the one-carbon-compound assimilation of a methylotroph, Hyphomicrobium methylovorum GM2, and its flanking regions were isolated using a DNA fragment encoding Escherichia coli SHMT as a probe. Nucleotide sequencing of the recombinant plasmids revealed the SHMT gene codes for the 434-amino-acid protein with a calculated molecular mass of 46 068 Da. The amino-acid sequence of the enzyme showed identity to the sequences of the enzymes from E. coli (55%) and rabbit liver (44%). The recombinant plasmid, which was constructed by ligation of the cloned gene and an expression vector pKK223-3, was introduced to an SHMT-deficient E. coli mutant ME5427 (glyA-). The transformed E. coli cells expressed SHMT, which was immunologically and enzymologically indistinguishable from the enzyme isolated from H. methylovorum GM2.Serine hydroxymethyltransferase (SHMT) catalyzes the reversible interconversion of serine and glycine, with tetrahydrofolate as the one-carbon ( C , ) acceptor. This enzyme activity is widely distributed in nature, being found in prokaryote and eukaryote. Its major functions are to provide glycine for protein and purine synthesis, and 5,lO-methylenetetrahydrofolate for the C , pool. Recently, primary structures of the enzymes from rabbit liver, Salmonella typhimurium, Bacillus stearothermophilus, Escherichia coli, Bradyrhizobium japonicum and Campilobacter jejuni have been determined [l -71. A number of methylotrophic bacteria possess the serine pathway for the assimilation of C , compounds, which provides precursors for the biosyntheses of cell components from C , substrates. In such bacteria, SHMT plays an important role as the first enzyme in the assimilation of C , compounds through the transfer of formaldehyde (via 5,lO-Correspondence to

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Identification of glyA as a symbiotically essential gene in Bradyrhizobium japonicum

Cited by 39 publications

References 35 publications

Nucleotide sequence and predicted functions of the entire Sinorhizobium meliloti pSymA megaplasmid

Nucleotide sequence and predicted functions of the entire Sinorhizobium meliloti pSymA megaplasmid

Genetics of the serine cycle in Methylobacterium extorquens AM1: cloning, sequence, mutation, and physiological effect of glyA, the gene for serine hydroxymethyltransferase

Molecular cloning and expression of the gene for serine hydroxymethyltransferase from an obligate methylotroph Hyphomicrobium methylovorum GM2

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