An orthologue of bacteroides fragilis NanH is the principal sialidase in tannerella forsythia
Abstract
Sialidase activity is a putative virulence factor of the anaerobic periodontal pathogen Tannerella forsythia, but it is uncertain which genes encode this activity. Characterization of a putative sialidase, SiaHI, by others, indicated that this protein alone may not be responsible for all of the sialidase activity. We describe a second sialidase in T. forsythia (TF0035), an orthologue of Bacteroides fragilis NanH, and its expression in Escherichia coli. Sialidase activity of the expressed NanH was confirmed by using 2′-(4-methylumbelliferyl)-α-d-N-acetylneuraminic acid as a substrate. Biochemical characterization of the recombinant T. forsythia NanH indicated that it was active over a broad pH range, with optimum activity at pH 5.5. This enzyme has high affinity for 2′-(4-methylumbelliferyl)-α-d-N-acetylneuraminic acid (Km of 32.9 ± 10.3 μM) and rapidly releases 4-methylumbelliferone (Vmax of 170.8 ± 11.8 nmol of 4-methylumbelliferone min−1 mg of protein−1). E. coli lysates containing recombinant T. forsythia NanH cleave sialic acid from a range of substrates, with a preference for α2-3 glycosidic linkages. The genes adjacent to nanH encode proteins apparently involved in the metabolism of sialic acid, indicating that the NanH sialidase is likely to be involved in nutrient acquisition.Citation
An orthologue of bacteroides fragilis NanH is the principal sialidase in tannerella forsythia 2009, 191 (11):3623-3628 Journal of BacteriologyPublisher
American Society for MicrobiologyJournal
Journal of BacteriologyAdditional Links
http://jb.asm.org/cgi/doi/10.1128/JB.01618-08Type
ArticleLanguage
enISSN
0021-9193ae974a485f413a2113503eed53cd6c53
10.1128/JB.01618-08
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