A preliminary analysis of Bifidobacterium longum exported proteins by two-dimensional electrophoresis.
Extracellular proteins of Bifidobacterium longum may mediate important interactions with the host. Here, we report on a comprehensive analysis of such proteins by using protein-free culture conditions and two-dimensional gel electrophoresis followed by mass spectrometry for protein identification. Seventeen proteins were detected in the culture supernatant, and 14 of them could be identified. Among these were 3 hypothetical solute-binding proteins of ABC transporters, an invasion-associated protein homolog, putative enzymes catalyzing cell wall turnover, several polypeptides with similarity to bacterial conjugation proteins, and 3 proteins of unknown function. Surprisingly, aldolase, usually considered as a cytoplasmic protein, was found in the culture supernatant. All proteins, excluding aldolase, were predicted to contain a signal peptide and a signal peptide cleavage site in their immature form. Some of the excreted proteins are interesting targets for further genetic and physiological studies.
Sánchez
Borja
B
Unité Flore Lactique et Environnement Carné, UR309, INRA, Jouy-en-Josas, France.
Champomier-Vergès
Marie-Christine
MC
Anglade
Patricia
P
Baraige
Fabienne
F
de Los Reyes-Gavilán
Clara G
CG
Margolles
Abelardo
A
Zagorec
Monique
M
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D001644:Bifidobacterium / Q000254:growth & development / Q000378:metabolism*; D017077:Culture Media, Conditioned / Q000737:chemistry; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D010455:Peptides / Q000737:chemistry; D021382:Protein Sorting Signals
D001426:Bacterial Proteins; D017077:Culture Media, Conditioned; D010455:Peptides; D021382:Protein Sorting Signals