Peer-Reviewed Journal Details
Mandatory Fields
Ryan, SM,Fitzgerald, GF,van Sinderen, D
2005
July
Applied and Environmental Microbiology
Transcriptional regulation and characterization of a novel beta-fructofuranosidase-encoding gene from Bifidobacterium breve UCC2003
Validated
Optional Fields
CARBON CATABOLITE REPRESSION LACTIC-ACID BACTERIA STREPTOMYCES-COELICOLOR GLUCOSE KINASE STAPHYLOCOCCUS-XYLOSUS ESCHERICHIA-COLI OLIGOSACCHARIDES OLIGOFRUCTOSE PURIFICATION METABOLISM
71
3475
3482
An operon involved in fructooligosaccharide breakdown was identified in the genome of Bifidobacterium breve UCC2003. This 2.6-kb transcriptional unit was comprised of three genes that encoded a putative permease, a conserved hypothetical protein, and a beta-fructofuranosidase. Active transcription of the operon was observed when B. breve UCC2003 was grown on sucrose or Actilight, while transcription appeared to be repressed when the organism was grown on glucose, fructose, a combination of glucose and sucrose, or a combination of fructose and sucrose. The beta-fructofuranosidase encoded by this operon was purified and biochemically characterized. The optimum pH and temperature for catalytic activity were determined to be pH 6.0 and 37 degrees C, respectively, and there was a dependence on bivalent cations, particularly manganese. The K-m and V-max values for sucrose hydrolysis were determined to be 25 +/- 2 mM and 24 +/- 3 mu mol min(-1) mg(-1), respectively. Interestingly, the enzyme was shown to specifically catalyze cleavage of the beta(2-1) glycosidic bond between glucose and its neighboring fructose moiety in sucrose and other fructooligosaccharides with a relatively low degree of polymerization, and there was no detectable activity towards the beta(2-1) glycosidic bond between two fructose moieties within the same substrate. To our knowledge, such an enzymatic activity has not previously been described in bifidobacteria or other gram-positive bacteria.
10.1128/AEM.71.7.3475-3482.2005
Grant Details