A Minimal Tat System from a Gram-positive Organism

Barnett, James P.; Eijlander, Robyn T.; Kuipers, Oscar P.; Robinson, Colin

doi:10.1074/jbc.m708134200

Cited by 64 publications

(23 citation statements)

References 39 publications

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“…Another feature to be addressed here is the presence of Sec-independent Tat pathway genes for folded proteins’ secretion. Twin-arginine translocase subunits A and C are presented in PM4 and S5 genomes, which may be functional in an analogy with a Gram-positive bacterial Tat system, known to work without additional TatB protein33.…”

Section: Resultsmentioning

confidence: 99%

Biology of archaea from a novel family Cuniculiplasmataceae (Thermoplasmata) ubiquitous in hyperacidic environments

Golyshina

Kublanov

Tran

et al. 2016

Sci Rep

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The order Thermoplasmatales (Euryarchaeota) is represented by the most acidophilic organisms known so far that are poorly amenable to cultivation. Earlier culture-independent studies in Iron Mountain (California) pointed at an abundant archaeal group, dubbed ‘G-plasma’. We examined the genomes and physiology of two cultured representatives of a Family Cuniculiplasmataceae, recently isolated from acidic (pH 1–1.5) sites in Spain and UK that are 16S rRNA gene sequence-identical with ‘G-plasma’. Organisms had largest genomes among Thermoplasmatales (1.87–1.94 Mbp), that shared 98.7–98.8% average nucleotide identities between themselves and ‘G-plasma’ and exhibited a high genome conservation even within their genomic islands, despite their remote geographical localisations. Facultatively anaerobic heterotrophs, they possess an ancestral form of A-type terminal oxygen reductase from a distinct parental clade. The lack of complete pathways for biosynthesis of histidine, valine, leucine, isoleucine, lysine and proline pre-determines the reliance on external sources of amino acids and hence the lifestyle of these organisms as scavengers of proteinaceous compounds from surrounding microbial community members. In contrast to earlier metagenomics-based assumptions, isolates were S-layer-deficient, non-motile, non-methylotrophic and devoid of iron-oxidation despite the abundance of methylotrophy substrates and ferrous iron in situ, which underlines the essentiality of experimental validation of bioinformatic predictions.

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Section: Resultsmentioning

confidence: 99%

Biology of archaea from a novel family Cuniculiplasmataceae (Thermoplasmata) ubiquitous in hyperacidic environments

Golyshina

Kublanov

Tran

et al. 2016

Sci Rep

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“…To standardize nomenclature between organisms, we will refer to this complex as Tat(A)BC complex. In Gram-positive bacteria, the sole TatA and TatC subunits can also be recovered from separate TatAC and TatA complexes [87]. Despite the fact that Tat subunits are consistently recovered from these Tat(A)BC and TatA complexes, doubt has been cast on the functional relevance of those isolatable structures.…”

Section: The Components Of Tat Translocases (A) Homologues Of Tatc Anmentioning

confidence: 99%

Twin-arginine-dependent translocation of folded proteins

Fröbel

Rose

Müller

2012

Phil. Trans. R. Soc. B

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Twin-arginine translocation (Tat) denotes a protein transport pathway in bacteria, archaea and plant chloroplasts, which is specific for precursor proteins harbouring a characteristic twin-arginine pair in their signal sequences. Many Tat substrates receive cofactors and fold prior to translocation. For a subset of them, proofreading chaperones coordinate maturation and membrane-targeting. Tat translocases comprise two kinds of membrane proteins, a hexahelical TatC-type protein and one or two members of the single-spanning TatA protein family, called TatA and TatB. TatC-and TatAtype proteins form homo-and hetero-oligomeric complexes. The subunits of TatABC translocases are predominantly recovered from two separate complexes, a TatBC complex that might contain some TatA, and a homomeric TatA complex. TatB and TatC coordinately recognize twin-arginine signal peptides and accommodate them in membrane-embedded binding pockets. Advanced binding of the signal sequence to the Tat translocase requires the proton-motive force (PMF) across the membranes and might involve a first recruitment of TatA. When targeted in this manner, folded twin-arginine precursors induce homo-oligomerization of TatB and TatA. Ultimately, this leads to the formation of a transmembrane protein conduit that possibly consists of a pore-like TatA structure. The translocation step again is dependent on the PMF.

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“…Considering that components from other bacterial TAT systems can work efficiently in E. coli (43,44), EfeB and TatCA were coexpressed in E. coli dEAD. EfeB could be observed in the supernatant of dEAD/ efeB-TatCA by SDS-PAGE, which suggested that a large amount of EfeB was exported.…”

Section: Discussionmentioning

confidence: 99%

Identification of a Novel Dye-Decolorizing Peroxidase, EfeB, Translocated by a Twin-Arginine Translocation System in Streptococcus thermophilus CGMCC 7.179

Zhang

Xin

Wang

et al. 2015

Appl Environ Microbiol

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Streptococcus thermophilus is a facultative anaerobic bacterium that has the ability to grow and survive in aerobic environments, but the mechanism for this remains unclear. In this study, the efeB gene, encoding a dye-decolorizing peroxidase, was identified in the genome of Streptococcus thermophilus CGMCC 7.179, and purified EfeB was able to decolorize reactive blue 5. Strikingly, genes encoding two components (TatA and TatC) of the twin-arginine translocation (TAT) system were also found in the same operon with the efeB gene. Knocking out efeB or tatC resulted in decreased growth of the strain under aerobic conditions, and complementation of the efeB-deficient strains with the efeB gene enhanced the biomass of the hosts only in the presence of the tatC gene. Moreover, it was proved for both S. thermophilus CGMCC 7.179 and Escherichia coli DE3 that EfeB could be translocated by the TAT system of S. thermophilus. In addition, the transcriptional levels of efeB and tatC increased when the strain was cultured under aerobic conditions. Overall, these results provide the first evidence that EfeB plays a role in protecting cells of S. thermophilus from oxidative stress, with the assistance of the TAT system. Streptococcus thermophilus is a Gram-positive bacterium of the genus Streptococcus, which comprises several harmful pathogenic species, such as Streptococcus pyogenes and Streptococcus pneumoniae. With long-term usage in fermented dairy products, S. thermophilus has lost its virulence-related genes and is given a "generally recognized as safe" (GRAS) status. This organism is commonly used with Lactobacillus delbrueckii subsp. bulgaricus or other lactobacilli for yogurt making as well as for the production of mozzarella, Swiss, and cheddar cheeses (1, 2).However, S. thermophilus encounters various stress conditions during the fermentation and storage processes (3). Among these environmental stresses, the presence of toxic reactive oxygen species (ROS) is the most important survival challenge, as it affects the organism's growth, fermentative capabilities, and viability and, consequently, the texture and flavor of the final fermented products (4). Though S. thermophilus cannot eliminate oxygen by respiration and lacks catalase activity (5), it can grow in the presence of oxygen and has an inducible capacity to survive in the presence of low concentrations of superoxide and hydroxyl radicals (6, 7), suggesting that this bacterium has evolved a specific inducible defensive system against ROS damage.In S. thermophilus, a single H 2 O-forming NADH oxidase is found, which could reduce the amount of intracellular O 2 (8). A well-characterized antioxidant enzyme in S. thermophilus is the manganese-containing superoxide dismutase (SodA), which converts superoxide anions to molecular oxygen and hydrogen peroxide, and the activity of SodA is not regulated by O 2 (9). Recently, a functional thioredoxin system composed of NADPH, a thioredoxin reductase, and thioredoxin was identified in S. thermophilus (10). This system provi...

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A Minimal Tat System from a Gram-positive Organism

Cited by 64 publications

References 39 publications

Biology of archaea from a novel family Cuniculiplasmataceae (Thermoplasmata) ubiquitous in hyperacidic environments

Biology of archaea from a novel family Cuniculiplasmataceae (Thermoplasmata) ubiquitous in hyperacidic environments

Twin-arginine-dependent translocation of folded proteins

Identification of a Novel Dye-Decolorizing Peroxidase, EfeB, Translocated by a Twin-Arginine Translocation System in Streptococcus thermophilus CGMCC 7.179

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