Investigation of the interaction among the components of the cytolethal distending toxin of Haemophilus ducreyi

Kaiping Deng, Jo L. Latimer, D. A. Lewis, Eric J. Hansen

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

The cytolethal distending toxin (CDT) of Haemophilus ducreyi is encoded by the cdtABC genes, but the composition of active CDT is not known. Both immunoaffinity and metal affinity chromatographic methods were used to purify H. ducreyi CDT from recombinant Escherichia coli strains bearing wild-type or mutated H. ducreyi cdtABC genes. Both affinity-purified preparations contained CdtA, CdtB, and CdtC proteins. These purification efforts also revealed that the formation of a noncovalent CdtB-CdtC complex and production of a fully active CDT complex required the presence of a functional CdtA protein. When purified recombinant CdtB and CdtC proteins were mixed, only very slight CDT activity was detected. In contrast, when a bacterial cell extract containing CdtA was mixed with purified preparations of both CdtB and CdtC, full CDT activity was reconstituted in vitro. These results indicate that CdtA is essential for norreal H. ducreyi CDT activity and that CdtA likely modifies or alters either CdtB or CdtC or both to form the active CDT complex.

Original languageEnglish (US)
Pages (from-to)609-615
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume285
Issue number3
DOIs
StatePublished - Jan 1 2001

Keywords

  • Affinity purification
  • Cytolethal distending toxin
  • Haemophilus ducreyi
  • Protein interactions

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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