The Streptococcus pneumoniae beta-galactosidase is a surface protein

• Published in: Journal of bacteriology Vol. 182; no. 20; pp. 5919 - 5921
• Main Authors: Zähner, D, Hakenbeck, R
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01.10.2000
• Series: Note
• Subjects: Amino Acid Sequence; Amino acids; Bacteriology; beta-Galactosidase - chemistry; beta-Galactosidase - genetics; beta-Galactosidase - metabolism; bgaA gene; Cell Membrane - enzymology; Enzymes and Proteins; glycosyl hydrolase; lactose; lacZ gene; Molecular Sequence Data; Mutagenesis, Site-Directed; Pneumonia; Protein Sorting Signals - chemistry; Protein Sorting Signals - metabolism; Proteins; Reading Frames; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism; Sequence Alignment; Sequence Homology, Amino Acid; Streptococcus pneumoniae; Streptococcus pneumoniae - enzymology; Streptococcus pneumoniae - genetics; Trypsin
• ISSN: 0021-9193; 1098-5530
• DOI: 10.1128/JB.182.20.5919-5921.2000

The beta-galactosidase gene of Streptococcus pneumoniae, bgaA, encodes a putative 2,235-amino-acid protein with the two amino acid motifs characteristic of the glycosyl hydrolase family of proteins. In addition, an N-terminal signal sequence and a C-terminal LPXTG motif typical of surface-associated proteins of gram-positive bacteria are present. Trypsin treatment of cells resulted in solubilization of the enzyme, documenting that it is associated with the cell envelope. In order to obtain defined mutants suitable for lacZ reporter experiments, the bgaA gene was disrupted, resulting in a complete absence of endogenous beta-galactosidase activity. The results are consistent with beta-galactosidase being a surface protein that seems not to be involved in lactose metabolism but that may play a role during pathogenesis.