Isolation and characterisation of promoter regions from<i>Streptococcus thermophilus</i>

Constable, Anne; Mollet, Beat

doi:10.1111/j.1574-6968.1994.tb07148.x

Cited by 14 publications

(3 citation statements)

References 19 publications

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“…In S . thermophilus , little is known about promoters but at least half of those that have been studied presented a putative or an identified extended −10 region [32–36] (sequences from Genbank & Swisspot databases). This extended −10 region has been reported to constitute a −35‐independent promoter consensus and the TG motif is an important requirement for efficient initiation of transcription at such promoters [37].…”

Section: Discussionmentioning

confidence: 99%

PepS from Streptococcus thermophilus

Fernández-Esplá

Rul

1999

European Journal of Biochemistry

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The proteolytic system of lactic acid bacteria is essential for bacterial growth in milk but also for the development of the organoleptic properties of dairy products. Streptococcus thermophilus is widely used in the dairy industry.In comparison with the model lactic acid bacteria Lactococcus lactis, S. thermophilus possesses two additional peptidases (an oligopeptidase and the aminopeptidase PepS). To understand how S. thermophilus grows in milk, we purified and characterized this aminopeptidase. PepS is a monomeric metallopeptidase of <45 kDa with optimal activity in the range pH 7.5±8.5 and at 55 8C on Arg-paranitroanilide as substrate. PepS exhibits a high specificity towards peptides possessing arginine or aromatic amino acids at the N-terminus. From the N-terminal protein sequence of PepS, we deduced degenerate oligonucleotides and amplified the corresponding gene by successive PCR reactions. The deduced amino-acid sequence of the PepS gene has high identity (40±50%) with the aminopeptidase T family from thermophilic and extremophilic bacteria; we thus propose the classification of PepS from S. thermophilus as a new member of this family. In view of its substrate specificity, PepS could be involved both in bacterial growth by supplying amino acids, and in the development of dairy products' flavour, by hydrolysing bitter peptides and liberating aromatic amino acids which are important precursors of aroma compounds.Keywords: aminopeptidase T family; lactic acid bacteria; peptidase; Streptococcus thermophilus. Aminopeptidases (EC 3.4.11) are ubiquitous enzymes, frequently observed in animals, plants and microorganisms. As exopeptidases, they catalyse the release of free amino acids from peptides. They are involved in many different functions in the cell, such as protein maturation, protein turnover, hydrolysis of regulatory peptides, nitrogen nutrition, modulation of gene expression etc. and, consequently, are considered essential enzymes.Aminopeptidases, and more generally the proteolytic system of lactic acid bacteria (LAB) ± which are used as starters in food fermentation processes ± are essential for the nitrogen nutrition of LAB and also for the development of the organoleptic properties of dairy products (texture and flavour). Indeed, LAB are auxotrophic for several amino acids and therefore depend highly on their proteolytic system to hydrolyse milk proteins (caseins) into assimilable nitrogen compounds (small peptides and free amino acids). This proteolytic system has been studied extensively in Lactococcus lactis which is the best known species among LAB. The proteolytic cascade of casein utilization in this bacterium is now well known. This multienzymatic system is composed of a cell-wall bound proteinase, responsible for the first step of casein hydrolysis, as well as several peptide and amino-acid transport systems, and of various intracellular peptidases, mainly aminopeptidases, which are involved in further hydrolysis of the peptides produced from caseins after their transport into the cell (for...

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Section: Discussionmentioning

confidence: 99%

PepS from Streptococcus thermophilus

Fernández-Esplá

Rul

1999

European Journal of Biochemistry

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“…To our knowledge, this is the first study on the characterization of an S. thermophilus phage promoter. By contrast, several promoters have been studied in various S. thermophilus strains (43)(44)(45)(46)(47) and other lactic acid bacteria phages (1,3,11,24,35,36,58,59). The P1 promoter possesses the bacterial consensus promoter sequence, while the promoter of the pts operon differs from the consensus by one nucleotide (TTGATA-N 17 -TATAAT).…”

Section: Resultsmentioning

confidence: 99%

Characterization of the cro-ori Region of the Streptococcus thermophilus Virulent Bacteriophage DT1

Lamothe

Lévesque

Bissonnette

et al. 2005

Appl Environ Microbiol

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The virulent cos-type Streptococcus thermophilus phage DT1 was previously isolated from a mozzarella whey sample, and its complete genomic sequence is available. The putative ori of phage DT1 is characterized by three inverted and two direct repeats located in a noncoding region between orf36 and orf37. As the replication ability of the putative ori and flanking genes could not be established, its ability to confer phage resistance was tested. When ori is cloned on a high-copy-number plasmid, it provides protection to S. thermophilus strains against phage infection during milk fermentation. This protection is phage specific and strain dependent. Then, a detailed transcriptional map was established for the region located between the cro-like gene (orf29) and the ori. The results of the Northern blots indicated that the transcription of this region started 5 min after the onset of phage infection. Comparative analysis of the expression of the cro-ori region in the three S. thermophilus cos-type phages DT1, Sfi19 (virulent), and Sfi21 (temperate) reveals significant differences in the number and size of transcripts. The promoter upstream of orf29 was further investigated by primer extension analysis, and its activity was confirmed by a chloramphenicol acetyltransferase assay, which showed that the phage promoter is more efficient than the constitutive bacterial promoter of the S. thermophilus operon encoding the general proteins of the phosphoenolpyruvate:sugar phosphotransferase system. However, the phage promoter is less efficient than the pts promoter in Lactococcus lactis and in Escherichia coli.Thermophilic lactic acid bacteria, such as Streptococcus thermophilus, are widely used as starter cultures in many yogurtand cheese-manufacturing processes. Bacteriophage infection of these lactic acid bacteria is the main factor impairing lactic acid fermentations, which ultimately decreases the efficiency of the production process and the value of the final product.S. thermophilus phages are currently classified into two general groups based on their mode of DNA packaging and their major structural proteins (27). The first group includes phages with cohesive genome extremities (cos type), and the second group contains phages with a DNA packaging scheme that proceeds via a headful mechanism (pac type) (27). To date, the complete nucleotide sequence of six S. thermophilus phage genomes is available through public databases: four cos-type phages, Sfi21 (temperate) (6), DT1 (virulent) (52), Sfi19 (virulent) (33), and 7201 (virulent) (49), and two pac-type phages, O1205 (temperate) (48) and Sfi11 (virulent) (31). Comparative analysis indicated a close genetic relationship between temperate and virulent S. thermophilus phages. It was even proposed that virulent S. thermophilus phages were derived from temperate phages by a combination of rearrangements and deletion events within the lysogeny module (4, 33). Despite these genetic modifications in the lysogeny module, a gene coding for a cro-like repressor is still found amon...

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“…To promote gene expression in ST cultures, the construction of first‐generation heterologous cloning vectors was reported by several laboratories [2,4–6,18,19,25]. Subsequently, second‐generation vectors with shuttle capacity incorporating the replication function of native S. thermophilus plasmids were also developed, and used to transport and express foreign genes in ST and other LAB strains [8–13,20].…”

Section: Introductionmentioning

confidence: 99%

Promoter activity of the pER341-borne ST_Phspin heterologous gene expression inEscherichia coliandStreptococcus thermophilus

Somkuti

Steinberg

1999

FEMS Microbiology Letters

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A 138-bp EcoO109/HinfI fragment of Streptococcus thermophilus plasmid pER341 (2798 bp) including the promoter sequence of the heat stress protein gene hsp16.4 was tested in vector constructs for ability to activate the promoterless green fluorescent protein gene (gfp) from a jelly fish in Escherichia coli, S. thermophilus, and lactococci. ST(Phsp) promoted gfp expression in transformed hosts as evidenced by the presence of green fluorescent (GFP(+)) colonies under UV illumination. The results confirmed the potential of ST(Phsp) as a functional promoter in heterologous gene expression in dairy fermentation bacteria.

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Isolation and characterisation of promoter regions fromStreptococcus thermophilus

Cited by 14 publications

References 19 publications

PepS from Streptococcus thermophilus

PepS from Streptococcus thermophilus

Characterization of the cro-ori Region of the Streptococcus thermophilus Virulent Bacteriophage DT1

Promoter activity of the pER341-borne ST_Phspin heterologous gene expression inEscherichia coliandStreptococcus thermophilus

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Isolation and characterisation of promoter regions fromStreptococcus thermophilus

Cited by 14 publications

References 19 publications

PepS from Streptococcus thermophilus

PepS from Streptococcus thermophilus

Characterization of the cro-ori Region of the Streptococcus thermophilus Virulent Bacteriophage DT1

Promoter activity of the pER341-borne STPhspin heterologous gene expression inEscherichia coliandStreptococcus thermophilus

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Promoter activity of the pER341-borne ST_Phspin heterologous gene expression inEscherichia coliandStreptococcus thermophilus