Identification of stress-inducible proteins in Lactobacillus delbrueckii subsp. bulgaricus

• Published in: Electrophoresis Vol. 21; no. 12; pp. 2557 - 2561
• Main Authors: Lim, Eng Mong, Ehrlich, S. Dusko, Maguin, Emmanuelle
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.07.2000; Wiley-VCH Verlag
• Subjects: Acid-stress proteins; Acids; Bacterial Proteins - analysis; Chaperonin 10 - analysis; Chaperonin 60 - analysis; Electrophoresis, Gel, Two-Dimensional - methods; Escherichia coli Proteins; Heat-shock; HSP70 Heat-Shock Proteins - analysis; Lactobacillus - chemistry; Lactobacillus bulgaricus; Life Sciences; Two-dimensional electrophoresis; EFFET DE LA TEMPERATURE
• ISSN: 0173-0835; 1522-2683
• DOI: 10.1002/1522-2683(20000701)21:12<2557::AID-ELPS2557>3.0.CO;2-B

Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) is a homofermentative bacterium that produces lactic acid during growth. We adapted the two‐dimensional electrophoresis (2‐DE) technique to study the response of this bacterium to acidity. De novo protein synthesis was monitoried by [35S]methionine labeling of exponentially growing cultures under standard (pH 6) and acidic (pH 4.75) conditions. After 2‐DE separation, the protein patterns were compared. The protein spots showing increased radioactivity levels under acid conditions were considered acid‐induced. We determined the N‐terminal amino acid sequence of three highly induced proteins; comparing these proteins to databases we identified them to be the well‐known heat shock proteins GroES, GroEL, and DnaK. Their induction levels were measured and compared. This is the first study by 2‐DE of stress response in L. bulgaricus. We established the method and present a protein map which will be useful for future studies.