Bovicin HJ50, a novel lantibiotic produced by Streptococcus bovis HJ50

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Streptococcus bovis HJ50 produces a lacticin 481-like 33-amino-acid-residue lantibiotic, designated bovicin HJ50. bovK-bovR in the bovicin HJ50 biosynthetic gene cluster is predicted to be a two-component signal transduction system involved in sensing signals and regulating gene expression. Disruption of bovK or bovR resulted in the abrogation of bovicin HJ50 production, suggesting both genes play important roles in bovicin HJ50 biosynthesis. Addition of exogenous bovicin HJ50 peptide to cultures of a bovM mutant that lost the capability for bovicin HJ50 production and structural gene bovA transcription in S. bovis HJ50 induced dose-dependent transcription of the bovA gene, demonstrating that bovicin HJ50 production was normally autoregulated. The transcription of bovA was no longer induced by bovicin HJ50 in bovK and bovR disruption mutants, suggesting that BovK-BovR plays an essential role in the signal transduction regulating bovicin HJ50 biosynthesis. A phosphorylation assay indicated that BovK has the ability to autophosphorylate and subsequently transfer the phosphoryl group to the downstream BovR protein to carry on signal transduction. Electromobility shift assays (EMSA) and green fluorescent protein (GFP) reporter gene expression assays showed the specific binding of BovR to the bovA promoter, indicating that BovR regulates bovA expression by direct binding between them. Taken together, bovicin HJ50 biosynthesis is induced by bovicin HJ50 itself and regulated via the two-component signal transduction system BovK-BovR.

mentioning

confidence: 99%

Autoregulation of Lantibiotic Bovicin HJ50 Biosynthesis by the BovK-BovR Two-Component Signal Transduction System in Streptococcus bovis HJ50

Teng

Liu

et al. 2011

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“…The disulfide bridge is rare in lantibiotics but was demonstrated here to be critical for suicin activity and has been previously underlined in bovicin HJ50 (35). A previous study showed that bovicin HJ50 could disrupt the membrane integrity of sensitive strain M. flavus NCIB8166, resulting in potassium efflux (45). Here, we found that suicin also disintegrated the cell membrane of M. flavus NCIB8166, leading to the disruption of membrane potential (Fig.…”

Section: Discussionsupporting

confidence: 53%

Restoration of Bioactive Lantibiotic Suicin from a Remnant lan Locus of Pathogenic Streptococcus suis Serotype 2

Wang

Gao

Teng

et al. 2014

cLantibiotics are ribosomally synthesized, posttranslationally modified antimicrobial peptides. Their biosynthesis genes are usually organized in gene clusters, which are mainly found in Gram-positive bacteria, including pathogenic streptococci. Three highly virulent Streptococcus suis serotype 2 strains (98HAH33, 05ZYH33, and SC84) have been shown to contain an 89K pathogenicity island. Here, on these islands, we unveiled and reannotated a putative lantibiotic locus designated sui which contains a virulence-associated two-component regulator, suiK-suiR. In silico analysis revealed that the putative lantibiotic modification gene suiM was interrupted by a 7.9-kb integron and that other biosynthesis-related genes contained various frameshift mutations. By reconstituting the intact suiM in Escherichia coli together with a semi-in vitro biosynthesis system, a putative lantibiotic named suicin was produced with bactericidal activities against a variety of Gram-positive strains, including pathogenic streptococci and vancomycin-resistant enterococci. Ring topology dissection indicated that the 34-amino-acid lantibiotic contained two methyllanthionine residues and one disulfide bridge, which render suicin in an N-terminal linear and C-terminal globular shape. To confirm the function of suiK-suiR, SuiR was overexpressed and purified. In vitro analysis showed that SuiR could specifically bind to the suiA gene promoter. Its coexpression with suiK could activate suiA gene promoter in Lactococcus lactis NZ9000. Conclusively, we obtained a novel lantibiotic suicin by restoring its production from the remnant sui locus and demonstrated that virulence-associated SuiK-SuiR regulates its production.

“…Bacteriocins produced by LAB such as Lactobacillus (12,25), Enterococcus (2,3,11,24,25), Leuconostoc (7,10), Streptococcus (22), and Carnobacterium (20,23) species have been frequently reported in previous studies. However, studies of bacteriocins from Weissella sp.…”

Section: Discussionmentioning

confidence: 99%

Weissellicin 110, a Newly Discovered Bacteriocin from Weissella cibaria 110, Isolated from Plaa-Som, a Fermented Fish Product from Thailand

Srionnual

Yanagida

Lin

et al. 2007

130

Weissella cibaria 110, isolated from the Thai fermented fish product plaa-som, was found to produce a bacteriocin active against some gram-positive bacteria. Bacteriocin activity was not eliminated by exposure to high temperatures or catalase but was destroyed by exposure to the proteolytic enzymes proteinase K and trypsin. The bacteriocin from W. cibaria 110 was purified, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the purified bacteriocin contained one protein band that was approximately 2.5 kDa in size. Mass spectrometry analysis showed the mass of the peptide to be approximately 3,487.8 Da. N-terminal amino acid sequence analysis was performed, and 27 amino acids were identified. Because it has no similarity to other known bacteriocins, this bacteriocin was defined as a new bacteriocin and termed weissellicin 110.Lactic acid bacteria (LAB) have long played important roles in food technology. The LAB include a wide variety of cell types with various physiological and biochemical characteristics. The isolation of LAB from milk products, fermented foods, and plants has frequently been reported. The phylogeny of the bacteria classified currently in the genus Weissella was clarified in 1990 (16), and the taxonomy of Weissella species was further assessed in 1993 (5). Weissella species have been isolated from a variety of sources, and some of them play important roles in fermentation (1). Weissella cibaria was first described by Björkroth et al.(1) and later found in various kinds of fermented foods (6,19).Bacteriocins are peptides produced by bacteria that kill or inhibit the growth of closely related bacteria. Bacteriocins produced by LAB have attracted special interest as potential safe, alternative food preservatives (4,8,15). Many bacteriocins associated with Lactobacillus, Enterococcus, and Leuconostoc species have been described previously (4). However, bacteriocins from Weissella species remain rare, and to our knowledge, no bacteriocins from W. cibaria (1, 9) have been reported previously.W. cibaria 110 (AB261010/DDBJ; DNA Data Bank of Japan [http://www.ddbj.nig.ac.jp/]) isolated from plaa-som (17), a fermented fish product from Thailand, was found to produce a bacteriocin active against some gram-positive bacteria. The present paper describes the purification and analysis of this bacteriocin and discusses its similarities to other known peptides. This is the first study to clarify the characteristics of a W. cibaria bacteriocin. MATERIALS AND METHODSW. cibaria 110. Ten strains of W. cibaria were isolated from plaa-som samples collected from Bangkok, Thailand, and their activities against the indicator strain Lactobacillus sakei JCM 1157 T were determined. Only strain 110 showed activity; this strain was identified using the API 50CHL kit, and the identification was confirmed using 16S rRNA sequence analysis. W. cibaria 110 was therefore used as the bacteriocin-producing strain in this study. Inhibitory activity was determined using the agar well diffusion assay described by ...