Dataset Information

Esterase SeE of Streptococcus equi ssp. equi is a novel nonspecific carboxylic ester hydrolase.

ABSTRACT: Extracellular carboxylic ester hydrolases are produced by many bacterial pathogens and have been shown recently to be important for virulence of some pathogens. However, these hydrolases are poorly characterized in enzymatic activity. This study prepared and characterized the secreted ester hydrolase of Streptococcus equi ssp. equi (designated SeE for S. equi esterase). SeE hydrolyzes ethyl acetate, acetylsalicylic acid, and tributyrin but not ethyl butyrate. This substrate specificity pattern does not match those of the three conventional types of nonspecific carboxylic ester hydrolases (carboxylesterases, arylesterases, and acetylesterases). To determine whether SeE has lipase activity, a number of triglycerides and vinyl esters were tested in SeE-catalyzed hydrolysis. SeE does not hydrolyze triglycerides and vinyl esters of long-chain carboxylic acids nor display interfacial activation, indicating that SeE is not a lipase. Like the conventional carboxylesterases, SeE is inhibited by di-isopropylfluorophosphate. These findings indicate that SeE is a novel carboxylesterase with optimal activity for acetyl esters.

SUBMITTER: Xie G

PROVIDER: S-EPMC2693102 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature

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Esterase SeE of Streptococcus equi ssp. equi is a novel nonspecific carboxylic ester hydrolase.

Xie Gang G Liu Mengyao M Zhu Hui H Lei Benfang B

FEMS microbiology letters 20081201 2

Extracellular carboxylic ester hydrolases are produced by many bacterial pathogens and have been shown recently to be important for virulence of some pathogens. However, these hydrolases are poorly characterized in enzymatic activity. This study prepared and characterized the secreted ester hydrolase of Streptococcus equi ssp. equi (designated SeE for S. equi esterase). SeE hydrolyzes ethyl acetate, acetylsalicylic acid, and tributyrin but not ethyl butyrate. This substrate specificity pattern d ...[more]

PMID: 19054107

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Project description:BACKGROUND: Streptococcus equi ssp. equi is the causative agent of 'Strangles' in horses. This is a debilitating condition leading to economic loss, yard closures and cancellation of equestrian events. There are multiple genotypes of S. equi ssp. equi which can cause disease, but to date there has been no systematic study of strains which are prevalent in Ireland. This study identified and classified Streptococcus equi ssp. equi strains isolated from within the Irish equine industry. RESULTS: Two hundred veterinary isolates were subjected to SLST (single locus sequence typing) based on an internal sequence from the seM gene of Streptococcus equi ssp equi. Of the 171 samples which successfully gave an amplicon, 162 samples (137 Irish and 24 UK strains) gave robust DNA sequence information. Analysis of the sequences allowed division of the isolates into 19 groups, 13 of which contain at least 2 isolates and 6 groups containing single isolates. There were 19 positions where a DNA SNP (single nucleotide polymorphism) occurs, and one 3 bp insertion. All groups had multiple (2-8) SNPs. Of the SNPs 17 would result in an amino acid change in the encoded protein. Interestingly, the single isolate EI8, which has 6 SNPs, has the three base pair insertion which is not seen in any other isolate, this would result in the insertion of an Ile residue at position 62 in that protein sequence. Comparison of the relevant region in the determined sequences with the UK Streptococcus equi seM MLST database showed that Group B (15 isolates) and Group I (2 isolates), as well as the individual isolates EI3 and EI8, are unique to Ireland, and some groups are most likely of UK origin (Groups F and M), but many more probably passed back and forth between the two countries. CONCLUSIONS: The strains occurring in Ireland are not clonal and there is a considerable degree of sequence variation seen in the seM gene. There are two major clades causing infection in Ireland and these strains are also common in the UK.

Project description:Streptococcus equi subsp. zooepidemicus (SEZ) has a wide host spectrum, including humans and domestic animals. The SEZ-caused swine streptococcicosis outbreak has occurred in several countries, and the swine-isolated strains usually have specific S. zooepidemicus M-like (szm) gene types. In this study, we found that the production of this specific szm gene (SzM protein) was an effective vaccine candidate. It could provide better protection with a 7-day interval immune procedure than the traditional vaccine strain ST171 and attenuate the strain ΔsezV against swine-isolated hypervirulent SEZ infections. According to this outcome, we developed monoclonal antibodies (McAbs) targeting the variable and conserved regions of this SzM protein, respectively. These McAbs all belong to the IgG1 isotype with a κ type light chain and have opsonophagocytic activity rather than agglutination or complement activation functions. We estimated the protection efficiency of the McAbs with 3 different passive immunotherapy programs. The anti-conserved region McAb can provide effective protection against swine-isolated SEZ infections with only the inconvenient immunotherapy program. It also partially works in preventing infection by other SEZ strains. In contrast, the anti-variable region McAb is only adapted to protect the host against a specific szm type SEZ strain isolated from pigs, but it is flexible for different immunotherapy programs. These data provide further information to guide the development of derived, genetically engineered McAbs that have potential applications in protecting hosts against swine-isolated, hypervirulent SEZ infections in the future. IMPORTANCE The swine-isolated SEZ, with its specific szm gene sequence, has impacted the pig feeding industry in China and North America and has led to serious economic loss. Though the SzM protein of SEZ has been proven to be an effective vaccine in preventing infection, most previous studies focused on horse-isolated strains, which have different szm gene types compared to swine-isolated strains. In this study, we developed the McAbs targeting the conserved and variable regions of this SzM protein from the swine-isolated hypervirulent strains and evaluated their protection efficiency. Our research provided information for the development of chimeric McAbs or other genetically engineered McAbs that have potential applications in protecting pigs against hypervirulent SEZ infections in the future.

Dataset Information

Esterase SeE of Streptococcus equi ssp. equi is a novel nonspecific carboxylic ester hydrolase.

Publications

Esterase SeE of Streptococcus equi ssp. equi is a novel nonspecific carboxylic ester hydrolase.

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