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Identification and characterization of the chromosomal yefM-yoeB toxin-antitoxin system of Streptococcus suis.

Zheng C, Xu J, Ren S, Li J, Xia M, Chen H, Bei W - Sci Rep (2015)

Bottom Line: Overproduction of S. suis YoeB toxin inhibited the growth of E. coli, and the toxicity of S. suis YoeB could be alleviated by the antitoxin YefM from S. suis and Streptococcus pneumoniae, but not by E. coli YefM.In a murine infection model, deletion of the yefM-yoeB locus had no effect on the virulence of S. suis serotype 2.Collectively, our data suggested that the yefM-yoeB locus of S. suis is an active TA system without the involvement of virulence.

View Article: PubMed Central - PubMed

Affiliation: 1] State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, 430070, China [2] Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.

ABSTRACT
Toxin-antitoxin (TA) systems are widely prevalent in the genomes of bacteria and archaea. These modules have been identified in Escherichia coli and various other bacteria. However, their presence in the genome of Streptococcus suis, an important zoonotic pathogen, has received little attention. In this study, we describe the identification and characterization of a type II TA system, comprising the chromosomal yefM-yoeB locus of S. suis. The yefM-yoeB locus is present in the genome of most serotypes of S. suis. Overproduction of S. suis YoeB toxin inhibited the growth of E. coli, and the toxicity of S. suis YoeB could be alleviated by the antitoxin YefM from S. suis and Streptococcus pneumoniae, but not by E. coli YefM. More importantly, introduction of the S. suis yefM-yoeB system into E. coli could affect cell growth. In a murine infection model, deletion of the yefM-yoeB locus had no effect on the virulence of S. suis serotype 2. Collectively, our data suggested that the yefM-yoeB locus of S. suis is an active TA system without the involvement of virulence.

No MeSH data available.


Related in: MedlinePlus

Multiple sequence alignments of the S. suis YefM-YoeB system with related homologs.The image was generated using program ESPript 3.0 (http://espript.ibcp.fr/ESPript/cgi-bin/ESPript.cgi). Identical residues are shown as white letters with red background, and similar residues are shown as red letters with white background. The predicted secondary structures of S. suis YefM and YoeB are shown at the top. α: α-helix; β: β-sheet; η: coil; T: turn. (a) Alignment of the YefM protein family. The GenBank accession numbers are as follows: S. suis YefM, YP_003025797.1; S. pneumoniae YefM, NP_359178.1; and E. coli YefM, NP_416521.2. (b) Alignment of the YoeB protein family. The conserved residues required for YoeB activity are labelled with triangles (Δ). The GenBank accession numbers are as follows: S. suis YoeB, YP_003025796.1; S. pneumoniae YoeB, NP_359177.1; and E. coli YoeB, YP_588458.1.
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f1: Multiple sequence alignments of the S. suis YefM-YoeB system with related homologs.The image was generated using program ESPript 3.0 (http://espript.ibcp.fr/ESPript/cgi-bin/ESPript.cgi). Identical residues are shown as white letters with red background, and similar residues are shown as red letters with white background. The predicted secondary structures of S. suis YefM and YoeB are shown at the top. α: α-helix; β: β-sheet; η: coil; T: turn. (a) Alignment of the YefM protein family. The GenBank accession numbers are as follows: S. suis YefM, YP_003025797.1; S. pneumoniae YefM, NP_359178.1; and E. coli YefM, NP_416521.2. (b) Alignment of the YoeB protein family. The conserved residues required for YoeB activity are labelled with triangles (Δ). The GenBank accession numbers are as follows: S. suis YoeB, YP_003025796.1; S. pneumoniae YoeB, NP_359177.1; and E. coli YoeB, YP_588458.1.

Mentions: To identify the YoeB toxin homologs, a BlastP search against the proteins annotated in the genome of S. suis SC8439 was performed, using the YoeB sequences of S. pneumoniae R6 and E. coli MG1655 as query sequences. Both searches revealed an open reading frame (SSUSC84_1817) encoding an 85 amino acid protein sharing 75% and 50% identity with the S. pneumoniae and E. coli YoeB toxins, respectively. Hence, the protein was termed YoeB. The YefM antitoxin encoded by SSUSC84_1818 was identified by the same method. BlastP analysis showed that the S. suis YefM has 79% and 29% amino acid sequence identity with YefM from S. pneumoniae and E. coli, respectively. Multiple sequence alignments further revealed that 1) the S. suis YefM-YoeB system shares high level of homology with that from S. pneumoniae and E. coli; 2) YoeB processes several conserved residues required for its activity (Glu46, Arg65, His83 and Tyr84)35 (Fig. 1). Protein homology modeling using CPHmodels predicted the structures of S. suis YefM and YoeB. The secondary structure of YefM is proposed to consist of four α-helices and three β-sheets (Fig. 1a), while that of YoeB contains two α-helices, five β-sheets and a coil (Fig. 1b). To determine whether the yefM-yoeB locus was universally present in the genomes of S. suis, BlastN analysis was performed using the 21 complete genomes of S. suis available in the National Centre for Biotechnology Information database as of 31 May 2015. The results confirmed that all strains harbour the yefM-yoeB locus, except for strain D12, a serotype 9 S. suis (see Supplementary Fig. S1 online).


Identification and characterization of the chromosomal yefM-yoeB toxin-antitoxin system of Streptococcus suis.

Zheng C, Xu J, Ren S, Li J, Xia M, Chen H, Bei W - Sci Rep (2015)

Multiple sequence alignments of the S. suis YefM-YoeB system with related homologs.The image was generated using program ESPript 3.0 (http://espript.ibcp.fr/ESPript/cgi-bin/ESPript.cgi). Identical residues are shown as white letters with red background, and similar residues are shown as red letters with white background. The predicted secondary structures of S. suis YefM and YoeB are shown at the top. α: α-helix; β: β-sheet; η: coil; T: turn. (a) Alignment of the YefM protein family. The GenBank accession numbers are as follows: S. suis YefM, YP_003025797.1; S. pneumoniae YefM, NP_359178.1; and E. coli YefM, NP_416521.2. (b) Alignment of the YoeB protein family. The conserved residues required for YoeB activity are labelled with triangles (Δ). The GenBank accession numbers are as follows: S. suis YoeB, YP_003025796.1; S. pneumoniae YoeB, NP_359177.1; and E. coli YoeB, YP_588458.1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4536659&req=5

f1: Multiple sequence alignments of the S. suis YefM-YoeB system with related homologs.The image was generated using program ESPript 3.0 (http://espript.ibcp.fr/ESPript/cgi-bin/ESPript.cgi). Identical residues are shown as white letters with red background, and similar residues are shown as red letters with white background. The predicted secondary structures of S. suis YefM and YoeB are shown at the top. α: α-helix; β: β-sheet; η: coil; T: turn. (a) Alignment of the YefM protein family. The GenBank accession numbers are as follows: S. suis YefM, YP_003025797.1; S. pneumoniae YefM, NP_359178.1; and E. coli YefM, NP_416521.2. (b) Alignment of the YoeB protein family. The conserved residues required for YoeB activity are labelled with triangles (Δ). The GenBank accession numbers are as follows: S. suis YoeB, YP_003025796.1; S. pneumoniae YoeB, NP_359177.1; and E. coli YoeB, YP_588458.1.
Mentions: To identify the YoeB toxin homologs, a BlastP search against the proteins annotated in the genome of S. suis SC8439 was performed, using the YoeB sequences of S. pneumoniae R6 and E. coli MG1655 as query sequences. Both searches revealed an open reading frame (SSUSC84_1817) encoding an 85 amino acid protein sharing 75% and 50% identity with the S. pneumoniae and E. coli YoeB toxins, respectively. Hence, the protein was termed YoeB. The YefM antitoxin encoded by SSUSC84_1818 was identified by the same method. BlastP analysis showed that the S. suis YefM has 79% and 29% amino acid sequence identity with YefM from S. pneumoniae and E. coli, respectively. Multiple sequence alignments further revealed that 1) the S. suis YefM-YoeB system shares high level of homology with that from S. pneumoniae and E. coli; 2) YoeB processes several conserved residues required for its activity (Glu46, Arg65, His83 and Tyr84)35 (Fig. 1). Protein homology modeling using CPHmodels predicted the structures of S. suis YefM and YoeB. The secondary structure of YefM is proposed to consist of four α-helices and three β-sheets (Fig. 1a), while that of YoeB contains two α-helices, five β-sheets and a coil (Fig. 1b). To determine whether the yefM-yoeB locus was universally present in the genomes of S. suis, BlastN analysis was performed using the 21 complete genomes of S. suis available in the National Centre for Biotechnology Information database as of 31 May 2015. The results confirmed that all strains harbour the yefM-yoeB locus, except for strain D12, a serotype 9 S. suis (see Supplementary Fig. S1 online).

Bottom Line: Overproduction of S. suis YoeB toxin inhibited the growth of E. coli, and the toxicity of S. suis YoeB could be alleviated by the antitoxin YefM from S. suis and Streptococcus pneumoniae, but not by E. coli YefM.In a murine infection model, deletion of the yefM-yoeB locus had no effect on the virulence of S. suis serotype 2.Collectively, our data suggested that the yefM-yoeB locus of S. suis is an active TA system without the involvement of virulence.

View Article: PubMed Central - PubMed

Affiliation: 1] State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, 430070, China [2] Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.

ABSTRACT
Toxin-antitoxin (TA) systems are widely prevalent in the genomes of bacteria and archaea. These modules have been identified in Escherichia coli and various other bacteria. However, their presence in the genome of Streptococcus suis, an important zoonotic pathogen, has received little attention. In this study, we describe the identification and characterization of a type II TA system, comprising the chromosomal yefM-yoeB locus of S. suis. The yefM-yoeB locus is present in the genome of most serotypes of S. suis. Overproduction of S. suis YoeB toxin inhibited the growth of E. coli, and the toxicity of S. suis YoeB could be alleviated by the antitoxin YefM from S. suis and Streptococcus pneumoniae, but not by E. coli YefM. More importantly, introduction of the S. suis yefM-yoeB system into E. coli could affect cell growth. In a murine infection model, deletion of the yefM-yoeB locus had no effect on the virulence of S. suis serotype 2. Collectively, our data suggested that the yefM-yoeB locus of S. suis is an active TA system without the involvement of virulence.

No MeSH data available.


Related in: MedlinePlus