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Reference map of soluble proteins from Streptococcus thermophilus by two‐dimensional electrophoresis
Author(s) -
Perrin Clarisse,
GonzálezMárquez Humberto,
Gaillard JeanLuc,
Bracquart Patrice,
Guimont Christiane
Publication year - 2000
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/(sici)1522-2683(20000301)21:5<949::aid-elps949>3.0.co;2-5
Subject(s) - streptococcus thermophilus , silver stain , isoelectric point , staining , isoelectric focusing , molecular mass , biology , methionine , thermus thermophilus , bacteria , gel electrophoresis , strain (injury) , microbiology and biotechnology , polyacrylamide gel electrophoresis , two dimensional gel electrophoresis , immobilized ph gradient , electrophoresis , biochemistry , chemistry , fermentation , amino acid , escherichia coli , enzyme , gene , genetics , proteomics , lactobacillus , anatomy
Streptococcus thermophilus is a lactic acid bacterium widely used for the production of fermented dairy products. The two‐dimensional electrophoresis (2‐DE) protein profile was obtained from three independent analyses of 2‐DE gels of soluble proteins of the strain PB18. About 270 spots were detected by silver staining and the average molecular weight and isoelectric point of each protein spot were calculated to be 41 600 and 5.2, respectively. Twelve proteins were purified by chromatographic techniques because their concentration was too low for direct sequencing from blots. Eleven were located in the PB18 2‐DE profile after silver staining. These preliminary results contribute to the setting up of a two‐dimensional image (or reference map) of the proteins from S. thermophilus in order to identify and compare strains of various origin or to follow metabolic process such as stress. Bidimensional autoradiographs of two strains (PB18 and ST105) of S. thermophilus grown in exponential phase at 42°C with [ 35 S]methionine were compared with an image analysis system. Among the eleven located proteins in the 2‐DE silver‐stained profile, nine were found in PB18 and eight in ST105 autoradiographs. One protein was specific to PB18. The eight proteins could play the role of internal 2‐D PAGE markers of p I and M r for S. thermophilus .