Cloning, nucleotide sequences, and overexpression in Escherichia coli of tandem copies of a tryptophanase gene in an obligately symbiotic thermophile, Symbiobacterium thermophilum

Hirahara, Toshikatsu; Suzuki, Shuichi; Horinouchi, Sueharu; Beppu, Teruhiko

doi:10.1128/aem.58.8.2633-2642.1992

Cited by 24 publications

(7 citation statements)

References 22 publications

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“…The traditional Gram-stain result indicates that S.thermophilum is Gram negative (5). The enterobacterialike ability of S.thermophilum that leads to tryptophanase (19) and tyrosinase (20) production also suggests that this bacterium is Gram negative. However, S.thermophilum lacks the major Gram-negative membrane biosynthesis proteins, such as LPS:glycosyltransferase and polysaccharide transporters.…”

Section: Cell Structurementioning

confidence: 99%

Genome sequence of Symbiobacterium thermophilum, an uncultivable bacterium that depends on microbial commensalism

Uéda

Yamashita

Ishikawa

et al. 2004

Nucleic Acids Research

148

101

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Symbiobacterium thermophilum is an uncultivable bacterium isolated from compost that depends on microbial commensalism. The 16S ribosomal DNA-based phylogeny suggests that this bacterium belongs to an unknown taxon in the Gram-positive bacterial cluster. Here, we describe the 3.57 Mb genome sequence of S.thermophilum. The genome consists of 3338 protein-coding sequences, out of which 2082 have functional assignments. Despite the high G + C content (68.7%), the genome is closest to that of Firmicutes, a phylum consisting of low G + C Gram-positive bacteria. This provides evidence for the presence of an undefined category in the Gram-positive bacterial group. The presence of both spo and related genes and microscopic observation indicate that S.thermophilum is the first high G + C organism that forms endospores. The S.thermophilum genome is also characterized by the widespread insertion of class C group II introns, which are oriented in the same direction as chromosomal replication. The genome has many membrane transporters, a number of which are involved in the uptake of peptides and amino acids. The genes involved in primary metabolism are largely identified, except those that code several biosynthetic enzymes and carbonic anhydrase. The organism also has a variety of respiratory systems including Nap nitrate reductase, which has been found only in Gram-negative bacteria. Overall, these features suggest that S.thermophilum is adaptable to and thus lives in various environments, such that its growth requirement could be a substance or a physiological condition that is generally available in the natural environment rather than a highly specific substance that is present only in a limited niche. The genomic information from S.thermophilum offers new insights into microbial diversity and evolutionary sciences, and provides a framework for characterizing the molecular basis underlying microbial commensalism.

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Section: Cell Structurementioning

confidence: 99%

Genome sequence of Symbiobacterium thermophilum, an uncultivable bacterium that depends on microbial commensalism

Uéda

Yamashita

Ishikawa

et al. 2004

Nucleic Acids Research

148

101

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“…The primary structures of Tnases from two strains of E. coli (Deeley & Yanofsky, 1981;Tokushige et al, 1989), P. vulgaris (Kamath & Yanofsky, 1992), S. thermophilum (Hirahara et al, 1992) and Enterobacter aerogenes SM-18 (Kawasaki et al, 1993) have been determined. The Tnase amino acid sequences exhibit an identity in the range 50% to 60%.…”

Section: Introductionmentioning

confidence: 99%

Crystal structure of tryptophanase

Isupov

Antson

Dodson

et al. 1998

Journal of Molecular Biology

114

106

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“…Homologs of E. coli tna genes are found in other gramnegative bacteria and have been cloned from Proteus vulgaris (21), Enterobacter aerogenes (24), and Symbiobacterium thermophilum (18); the organization of genes within the operon and the location of presumed regulatory sites are conserved among the enteric bacteria (21).…”

mentioning

confidence: 99%

The Tryptophanase Gene Cluster of Haemophilus influenzae Type b: Evidence for Horizontal Gene Transfer

et al. 1998

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Among strains of Haemophilus influenzae, the ability to catabolize tryptophan (as detected by indole production) varies and is correlated with pathogenicity. Tryptophan catabolism is widespread (70 to 75%) among harmless respiratory isolates but is nearly universal (94 to 100%) among strains causing serious disease, including meningitis. As a first step in investigating the relationship between tryptophan catabolism and virulence, we have identified genes in pathogenic H. influenzae which are homologous to the tryptophanase (tna) operon of Escherichia coli. The tna genes are located on a 3.1-kb fragment betweennlpD and mutS in the H. influenzaetype b (Eagan) genome, are flanked by 43-bp direct repeats of an uptake signal sequence downstream from nlpD, and appear to have been inserted as a mobile unit within this sequence. The organization of this insertion is reminiscent of pathogenicity islands. Thetna cluster is found at the same map location in all indole-positive strains of H. influenzae surveyed and is absent from reference type d and e genomes. In contrast to H. influenzae, most other Haemophilus species lacktna genes. Phylogenetic comparisons suggest that thetna cluster was acquired by intergeneric lateral transfer, either by H. influenzae or a recent ancestor, and thatE. coli may have acquired its tnaA gene from a related source. Genomes of virulent H. influenzae resemble those of pathogenic enterics in having an island of laterally transferred DNA next to mutS.

show abstract

Cloning, nucleotide sequences, and overexpression in Escherichia coli of tandem copies of a tryptophanase gene in an obligately symbiotic thermophile, Symbiobacterium thermophilum

Cited by 24 publications

References 22 publications

Genome sequence of Symbiobacterium thermophilum, an uncultivable bacterium that depends on microbial commensalism

Genome sequence of Symbiobacterium thermophilum, an uncultivable bacterium that depends on microbial commensalism

Crystal structure of tryptophanase

The Tryptophanase Gene Cluster of Haemophilus influenzae Type b: Evidence for Horizontal Gene Transfer

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