Dataset Information

Identification and characterization of amylase-binding protein C from Streptococcus mitis NS51.

ABSTRACT: A substantial proportion of the streptococcal species found in dental plaque biofilms are able to interact with the abundant salivary enzyme alpha-amylase. These streptococci produce proteins that specifically bind amylase. An important plaque species, Streptococcus mitis, secretes a 36-kDa amylase-binding protein into the extracellular milieu. Proteins precipitated from S. mitis NS51 cell culture supernatant by the addition of purified salivary amylase were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to a membrane, and a prominent 36-kDa band was cut from the membrane and sequenced to yield the N-terminal amino acid sequence DSQAQYSNGV. Searching the S. mitis genome sequence database revealed a single open reading frame containing this sequence, and the gene was amplified by the S. mitis genomic DNA polymerase chain reaction. The coding region of this open reading frame, designated amylase-binding protein C (AbpC), was cloned into an Escherichia coli expression vector and the recombinant AbpC (rAbpC) was purified from the soluble fraction of the E. coli cell lysate. Purified AbpC was found to interact with immobilized amylase, confirming AbpC as a new streptococcal amylase-binding protein.

SUBMITTER: Vorrasi J

PROVIDER: S-EPMC2862347 | biostudies-literature | 2010 Apr

REPOSITORIES: biostudies-literature

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Identification and characterization of amylase-binding protein C from Streptococcus mitis NS51.

Vorrasi J J Chaudhuri B B Haase E M EM Scannapieco F A FA

Molecular oral microbiology 20100401 2

A substantial proportion of the streptococcal species found in dental plaque biofilms are able to interact with the abundant salivary enzyme alpha-amylase. These streptococci produce proteins that specifically bind amylase. An important plaque species, Streptococcus mitis, secretes a 36-kDa amylase-binding protein into the extracellular milieu. Proteins precipitated from S. mitis NS51 cell culture supernatant by the addition of purified salivary amylase were separated by sodium dodecyl sulfate-p ...[more]

PMID: 20331802

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Project description:Streptococcus mitis is found in the oral cavity and nasopharynx and forms a significant portion of the human microbiome. In this study, in silico analyses indicated the presence of an Rgg regulator and short hydrophobic peptide (Rgg/SHP) cell-to-cell communication system in S. mitis Although Rgg presented greater similarity to a repressor in Streptococcus pyogenes, autoinducing assays and genetic mutation analysis revealed that in S. mitis Rgg acts as an activator. Transcriptome analysis showed that in addition to shp, the system regulates two other downstream genes, comprising a segment of a putative lantibiotic gene cluster that is in a conjugative element locus in different members of the mitis group. Close comparison to a similar lantibiotic gene cluster in Streptococcus pneumoniae indicated that S. mitis lacked the full set of genes. Despite the potential of SHP to trigger a futile cycle of autoinduction, growth was not significantly affected for the rgg mutant under normal or antibiotic stress conditions. The S. mitis SHP was, however, fully functional in promoting cross-species communication and increasing S. pneumoniae surface polysaccharide production, which in this species is regulated by Rgg/SHP. The activity of SHPs produced by both species was detected in cocultures using a S. mitis reporter strain. In competitive assays, a slight advantage was observed for the rgg mutants. We conclude that the Rgg/SHP system in S. mitis regulates the expression of its own shp and activates an Rgg/SHP system in S. pneumoniae that regulates surface polysaccharide synthesis. Fundamentally, cross-communication of such systems may have a role during multispecies interactions.IMPORTANCE Bacteria secrete signal molecules into the environment which are sensed by other cells when the density reaches a certain threshold. In this study, we describe a communication system in Streptococcus mitis, a commensal species from the oral cavity, which we also found in several species and strains of streptococci from the mitis group. Further, we show that this system can promote cross-communication with S. pneumoniae, a closely related major human pathogen. Importantly, we show that this cross-communication can take place during coculture. While the genes regulated in S. mitis are likely part of a futile cycle of activation, the target genes in S. pneumoniae are potentially involved in virulence. The understanding of such complex communication networks can provide important insights into the dynamics of bacterial communities.

Dataset Information

Identification and characterization of amylase-binding protein C from Streptococcus mitis NS51.

Publications

Identification and characterization of amylase-binding protein C from Streptococcus mitis NS51.

Similar Datasets

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