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An orthologue of bacteroides fragilis NanH is the principal sialidase in tannerella forsythia

  • Hayley Thompson
    ,
  • Karen A. Homer
    ,
  • Susmitha Rao
    ,
  • Veronica Booth
    ,
  • Arthur Hosie
  • King's College London
Research Output: Contribution to journal Article Peer-review

Open access

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.

Publication Information

Output type

Research Output: Contribution to journal Article Peer-review

Original language

English

Pages from-to (Number of pages)

Pages 3623-3628

Journal (Volume, Issue Number)

Journal of Bacteriology (Volume 191, Issue 11)

Publication milestones

  • Published - 01/06/2009

Publication status

Published - 01/06/2009

ISSN

0021-9193

External Publication IDs

  • handle.net: 10547/228318
  • Scopus: 66149143854

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