%0 Journal Article %A Aduse-Opoku, J. %A Tao, Lin %A Ferretti, J. J. %A Russell, R. R. B. %T Biochemical and genetic analysis of Streptococcus mutans α-galactosidase %D 1991 %J Microbiology, %V 137 %N 4 %P 757-764 %@ 1465-2080 %R https://doi.org/10.1099/00221287-137-4-757 %I Microbiology Society, %X The aga gene coding for α-galactosidase in Streptococcus mutans was detected in a recombinant gene library constructed in phage λ. The gene was subcloned into plasmid vectors and shown to specify a novel protein of M r 80000. Characterization of α-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 α-galactosidase, deduced from nucleotide sequencing of aga, gave a predicted M r of 82022 and revealed regions of homology to α-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 α-galactosidase activity and abolished the ability to ferment melibiose; α-glucosidase activity was also lost, due to an indirect effect on the dexB gene. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-137-4-757