Identification and analysis of a gene (abpA) encoding a major amylase-binding protein in Streptococcus gordonii.
Microbiology (Reading)
; 144 ( Pt 5): 1223-1233, 1998 May.
Article
em En
| MEDLINE
| ID: mdl-9611797
ABSTRACT
Oral streptococci such as Streptococcus gordonii bind the abundant salivary enzyme alpha-amylase. This interaction may be important in dental plaque formation and metabolism, thus contributing to the initiation and progression of dental caries and periodontal disease, the two most common plaque-mediated diseases. The conjugative transposon Tn916 was used to insertionally inactivate gene(s) essential to the expression of amylase-binding components of S. gordonii Challis, and a mutant deficient in amylase-binding (Challis Tn1) was identified. While wild-type strains of S. gordonii released both 20 kDa and 82 kDa amylase-binding proteins into culture supernatants, Challis Tn1 expressed the 82 kDa but not the 20 kDa protein. The 20 kDa amylase-binding protein was isolated from culture supernatants of S. gordonii Challis by hydroxyapatite chromatography. A partially purified, functionally active 20 kDa protein was sequenced from blots, and the N-terminal sequence obtained was found to be DEP(A)TDAAT(R)NND. A novel strategy, based on the single-specific-primer polymerase chain reaction technique, enabled the gene inactivated by Tn916 to be cloned. Analysis of the resultant nucleotide sequence revealed an open reading frame of 585 bp, designated amylase-binding protein A (abpA), encoding a protein of 20 kDa (AbpA), immediately downstream from the insertion site of Tn916. This protein possessed a potential signal peptide followed by a region having identity with the N-terminal sequence of the 20 kDa amylase-binding protein. These results demonstrate the role of the 20 kDa protein in the binding of amylase to S. gordonii. Knowledge of the nature of amylase-binding proteins may provide a better understanding of the role of these proteins in the colonization of S. gordonii in the oral cavity.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Streptococcus
/
Proteínas de Bactérias
/
Proteínas de Transporte
/
Genes Bacterianos
/
Amilases
Tipo de estudo:
Diagnostic_studies
Limite:
Humans
Idioma:
En
Revista:
Microbiology (Reading)
Assunto da revista:
MICROBIOLOGIA
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Estados Unidos