Title:Comparative Proteomic Analysis of Hydrogen Peroxide-induced Protein Expression in Streptococcus pneumoniae D39
VOLUME: 18
Author(s):Sungkyoung Lee, Myoung-Ro Lee, Songmee Bae and Min-Kyu Kwak*
Affiliation:Division of Bacterial Disease Research and Parasitic Diseases, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, 187 Osongsaengmyeong 2-ro, Osong-eup, Cheongju-si, Chungcheongbuk-do, 28160,, Division of Vectors and Parasitic Diseases, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, 187 Osongsaengmyeong 2-ro, Osong-eup, Cheongju-si, Chungcheongbuk-do, 28160,, Division of Antimicrobial Resistance, Center for Infectious Disease Research, Korea National Institute of Health; , Department of Food and Nutrition, Institute of Food and Nutrition Science, Eulji University, 553, Sanseong-daero, Seongnam, Gyeonggi-do, 13135
Keywords:High-throughput image analysis, hydrogen peroxide, LC-coupled ESI-MS/MS, MALDI-TOF, oxidative stress,
Streptococcus pneumoniae, two-dimensional gel electrophoresis
Abstract:Background: Streptococcus pneumoniae is a leading cause of human respiratory tract infection. Despite the lack
of activities of antioxidative enzymes, including cytochromes, hemoproteins, and peroxidases/catalases, traits conferring the
aerotolerant-anaerobic growth of this bacterium are conserved, with high efficacy of antioxidative actions, in an oxygen-rich
environment.
Objective: Through proteome analysis, this study’s intention was to evaluate differentially expressed proteins and/or gene
products modeled in a highly virulent strain, S. pneumoniae D39, exogenously-treated with millimolar concentrations of
H2O2.
Method: For two-dimensional gel electrophoresis (2-DE) analysis, following one dimensional isoelectric focusing with an
immobilized pH gradient of pH 4-7, the most significantly mobilized proteins expressed were separated by SDS-PAGE in
the second dimension. With a total of 431 protein spots detected, certain proteins were excised, in-gel trypsin digested, and
analyzed by combination with MALDI-TOF and LC-ESI-MS/MS for mass spectrometric peptide mapping and protein
identification. Utilizing mass spectrometry analysis of spots excised from 2-DE, the selected protein spots were identified
with a variety of databases and MASCOT.
Results: With the aid of comparisons to proteome reference maps, the most differentially expressed 38 proteins, those with
approximately 1.4-fold or more increase and/or decrease or with multiple isoforms exhibiting variable pI values, were
induced by treatment of exogenous 2 mM H2O2. The identified proteins were seen to be involved in pneumococcal
pathogenesis and primary metabolism, amongst others.
Conclusion: This is the first study to convincingly document proteomic information associated with pathophysiological
adaptation under the given oxidative conditions, and corresponding potential antioxidative mechanisms, in S. pneumoniae.
