Identification of NAD(+) synthetase from Streptococcus sobrinus as a B-cell-stimulatory protein

• Type: Article in International Scientific Journal
• Date: 2004

Authors

veiga-malta, i (Author) Other; duarte, m (Author) ICBAS; dinis, m (Author) Other; madureira, p (Author) Other; ferreira, p (Author) ICBAS; videira, a (Author) ICBAS

Journal

Title: Journal of Bacteriology

Vol. 186

Pages: 419-426

ISSN: 0021-9193

Publisher: American Society for Microbiology

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 5 Citations

Other information

Authenticus ID: P-000-D14

DOI: 10.1128/jb.186.2.419-426.2004

Abstract (EN): Streptococcus sobrinus, one agent of dental caries, secretes a protein that induces lymphocyte polyclonal activation of the host as a mechanism of immune evasion. We have isolated from culture supernatants of this bacterium a protein with murine B-cell-stimulatory properties and subsequently cloned the relevant gene. It contains an open reading frame of 825 bp encoding a polypeptide with 275 amino acid residues and a molecular mass of 30 kDa. The protein displays high sequence homology with NAD(+) synthetases from several organisms, including a conserved fingerprint sequence (SGGXD) characteristic of ATP pyrophosphatases. The polypeptide was expressed in Escherichia coli as a hexahistidine-tagged protein and purified in an enzymatically active form. The recombinant NAD(+) synthetase stimulates murine B cells after in vitro treatment of spleen cell cultures, as demonstrated by its ability to induce up-regulation of the expression of CD69, an early marker of lymphocyte activation. Stimulation with the recombinant NAD(+) synthetase was also observed with other B-cell markers, such as CD19(+), B220(+), and CD21(+). Cell proliferation follows the activation induced by the recombinant NAD(+) synthetase.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8