title: [Effect of ClpE depletion on the bacterial protein expression profiles of Streptococcus pneumoniae].
abstract: OBJECTIVE
  To investigate the effect of ClpE on the protein expression profiles of Streptococcus pneumoniae.
  
  
  METHODS
  clpE-deficient Streptococcus pneumoniae strain was constructed by long flanking homology-polymerase chain reaction (LFH-PCR) and identified by PCR and sequencing. The total bacterial proteins were analyzed by two-dimensional gel electrophoresis and imaging analysis, and the differentially expressed protein spots were excised by dot-gel digestion with trypsin. Peptide mass fingerprinting (PMF) was obtained by analysis of the fragment length by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The PMF was analyzed using software to identify the proteins.
  
  
  RESULTS
  The number of matched protein spots of the two gels was 61%. By sequence database searching, 4 out of the 17 differential protein spots were identified, namely hypoxanthine-guanine, pyrrolidone-carboxylate peptidase1, formate-tetrahydrofolate ligase, and bifunctional protein pyrR.
  
  
  CONCLUSIONS
  clpE gene-deficient Streptococcus pneumoniae expresses fewer kinds of proteins at also lower levels than the wild-type bacteria, suggesting that ClpE allows the bacteria to adapt to different host environments by inducing the expression of special proteins.
authors.affiliation: Key Laboratory of Laboratory Medical Diagnostics of Ministry of Education, Chongqing Medical University, Chongqing 400016, China. zhangqun198166@163.com
authors.forename: Qun
authors.initials: Q
authors.lastname: Zhang
authors.forename: Nan-lin
authors.initials: NL
authors.lastname: Yin
authors.forename: Xue-mei
authors.initials: XM
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Ya-li
authors.initials: YL
authors.lastname: Cui
authors.forename: Yi-bing
authors.initials: YB
authors.lastname: Yin
authors.forename: Wen-chun
authors.initials: WC
authors.lastname: Xu
mesh_terms: D000251:Adenosine Triphosphatases / Q000172:deficiency* / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D015180:Electrophoresis, Gel, Two-Dimensional; D020869:Gene Expression Profiling; D006360:Heat-Shock Proteins / Q000172:deficiency* / Q000235:genetics*; D016133:Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000254:growth & development / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D000251:Adenosine Triphosphatases; C118340:ClpE protein, bacteria