Characterization of the anti-cancer-cell parasporal proteins of a Bacillus thuringiensis isolate

Can J Microbiol. 2000 Oct;46(10):913-9.


An unusual activity, associated with non-insecticidal and non-haemolytic parasporal inclusion proteins of a Bacillus thuringiensis soil isolate, designated 89-T-26-17, was characterized. The parasporal inclusion of this isolate was bipyramidal, rounded at both ends, containing proteins of 180, 150, 120, 100, and 88 kDa. No homologies with the Cry and Cyt proteins of B. thuringiensis were detected based on N-terminal sequences. Proteolytic processing of the inclusion proteins by proteinase K, trypsin, and chymotrypsin produced a major protein of 64 kDa exhibiting cytocidal activity against human leukaemic T cells and uterus cervix cancer (HeLa) cells. The protease-activated proteins showed no cytotoxicity to normal T cells.

MeSH terms

  • Amino Acid Sequence
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / metabolism
  • Antineoplastic Agents / pharmacology*
  • Bacillus thuringiensis / metabolism*
  • Bacillus thuringiensis / ultrastructure
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Bacterial Proteins / pharmacology*
  • Endopeptidase K / metabolism
  • HeLa Cells
  • Humans
  • Inclusion Bodies / chemistry*
  • Inclusion Bodies / ultrastructure
  • Leukemia, T-Cell
  • Molecular Sequence Data
  • Spores, Bacterial
  • Tumor Cells, Cultured


  • Antineoplastic Agents
  • Bacterial Proteins
  • Endopeptidase K