Amino sugars in the glycoprotein toxin from Bacillus thuringiensis subsp. israelensis

M. A. Pfannenstiel, G. Muthukumar, G. A. Couche, K. W. Nickerson

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

The carbohydrate content of purified Bacillus thuringiensis subsp. israelensis crystal toxin was determined by six biochemical tests, column chromatography on an amino acid analyzer, and the binding of 11 fluorescent lectins. The crystals contained approximately 1.0% neutral sugars and 1.7% amino sugars. The amino sugars consisted of 70% glucosamine and 30% galactosamine. No N-acetylneuraminic acid (sialic acid) was detected. The presence of amino sugars was confirmed by the strong binding of fluorescent wheat germ agglutinin and the weak binding of fluorescent soybean agglutinin. These lectins recognize N-acetyl-D-glucosamine and N-acetyl-D-galactosamine, respectively. The lectin-binding sites appeared evenly distributed among the protein subunits of the crystal. The sugars were covalently attached to the crystal toxin because wheat germ agglutinin still bound alkali-solubilized toxin which had been boiled in sodium dodecyl sulfate, separated by polyacrylamide gel electrophoresis, and transferred to nitrocellulose membranes. This study demonstrates the covalent attachment of amino sugars and indicates that the B. thuringiensis subsp. israelensis protein toxin should be viewed as glycoprotein toxins. The crystals used in the present study were purified on sodium bromide density gradients. Studies employing crystals purified on Renografin density gradients can give artificially high values for the anthrone test for neutral sugars.

Original languageEnglish (US)
Pages (from-to)796-801
Number of pages6
JournalJournal of bacteriology
Volume169
Issue number2
DOIs
StatePublished - 1987

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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