title: The Streptococcus pneumoniae beta-galactosidase is a surface protein.
abstract: 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.
authors.affiliation: Department of Microbiology, University of Kaiserslautern, D-67663 Kaiserslautern, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Zähner
authors.forename: R
authors.initials: R
authors.lastname: Hakenbeck
mesh_terms: D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000201:enzymology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D021382:Protein Sorting Signals / Q000737:chemistry / Q000378:metabolism; D016364:Reading Frames; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013296:Streptococcus pneumoniae / Q000201:enzymology* / Q000235:genetics*; D014357:Trypsin; D001616:beta-Galactosidase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
chemical_list: D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D001616:beta-Galactosidase; D014357:Trypsin