Mass Spectrometric Analysis of Whole Secretome and Amylase-precipitated Secretome Proteins from Streptococcus gordonii
- *Corresponding Author:
- Frank A Scannapieco, D.M.D., Ph.D
Professor and Chair
Department of Oral Biology School of Dental Medicine
State University of New York at Buffalo
109 Foster Hall, 3435 Main St. Buffalo, NY 14214, USA
Received Date: August 05, 2014; Accepted Date: September 01, 2014; Published Date: September 04, 2014
Citation: Maddi A, Haase EM, Scannapieco FA (2014) Mass Spectrometric Analysis of Whole Secretome and Amylase-precipitated Secretome Proteins from Streptococcus gordonii. J Proteomics Bioinform 7:287-295. doi: 10.4172/jpb.1000331
Copyright: © 2014 Maddi A, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Oral biofilm (dental plaque) is formed by the initial adhesion of “pioneer species” to salivary proteins that form the dental pellicle on the tooth surface. One such pioneer species, Streptococcus gordonii, is known to bind salivary amylase through specific amylase-binding proteins such as amylase-binding protein A (AbpA). Recent studies have demonstrated that once bound, salivary amylase appears to modulate gene expression in S. gordonii. However, it is not known if this amylase-induced gene expression leads to secretion of proteins that play a role in plaque biofilm formation. In this study we examined the differences in secreted proteomes between S. gordonii KS1 (wild type) and AbpA-deficient (ΔAbpA) strains. We also examined the differentially precipitated secretome proteins following incubation with salivary amylase. The culture supernatants from KS1 and ΔAbpA were analyzed by nano-LC/MS/ MS to characterize the whole secreted proteomes of the KS1 and ΔAbpA. A total of 107 proteins were identified in the KS1 and ΔAbpA secretomes of which 72 proteins were predicted to have an N-terminal signal peptide for secretion. Five proteins were differentially expressed between the KS1 and ΔAbpA secretomes; AbpA and sortase B were expressed exclusively by KS1, whereas Gdh, AdcA and GroEL were expressed only by ΔAbpA. Incubation of culture supernatants from KS1 and ΔAbpA with amylase (50 μg/ml) at room temperature for 2 h resulted in the differential precipitation of secretome proteins. Hypothetical protein (SGO_0483), cation-transporting ATPase YfgQ (Aha1), isocitrate dehydrogenase (Icd), sortase A (SrtA), beta-N-acetylhexosaminidase (SGO_0405), peptide chain release factor 1(PrfA) and cardiolipin synthase (SGO_2037) were precipitated by amylase from the KS1 culture supernatant. Among the identified secreted proteins and amylase-precipitated proteins, transcriptional regulator LytR (SGO_0535) and cation-transporting ATPase YfgQ (Aha1) are potential signaling proteins.