Format

Send to

Choose Destination
J Gen Microbiol. 1991 Apr;137(4):757-64.

Biochemical and genetic analysis of Streptococcus mutans alpha-galactosidase.

Author information

1
Hunterian Dental Research Unit, London Hospital Medical College, UK.

Abstract

The aga gene coding for alpha-galactosidase in Streptococcus mutans was detected in a recombinant gene library constructed in phage lambda. The gene was subcloned into plasmid vectors and shown to specify a novel protein of Mr 80,000. Characterization of alpha-galactosidase from S. mutans and from recombinant Escherichia coli expressing aga indicated that the enzyme functions as a tetramer. The amino acid composition of the alpha-galactosidase, deduced from nucleotide sequencing of aga, gave a predicted Mr of 82,022 and revealed regions of homology to alpha-galactosidases encoded by the E. coli Raf plasmids and by Bacillus stearothermophilus. Inactivation of the aga gene in S. mutans resulted in loss of all alpha-galactosidase activity and abolished the ability to ferment melibiose; alpha-glucosidase activity was also lost, due to an indirect effect on the dexB gene.

PMID:
1649890
DOI:
10.1099/00221287-137-9-2271
[Indexed for MEDLINE]

Supplemental Content

Loading ...
Support Center