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

• Tipo: Artigo em Revista Científica Internacional
• Data: 2004

Autores

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

Revista

Título: Journal of Bacteriology

Vol. 186

Páginas: 419-426

ISSN: 0021-9193

Editora: American Society for Microbiology

Indexação

ISI Web of Knowledge - 3 Citações

Scopus - 5 Citações

Outras Informações

ID Authenticus: 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.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 8