Parasporin-2Ab, a newly isolated cytotoxic crystal protein from Bacillus thuringiensis

Tohru Hayakawa, Rie Kanagawa, Yosuke Kotani, Mayumi Kimura, Masashi Yamagiwa, Yoshiharu Yamane, So Takebe, Hiroshi Sakai

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


A novel crystal protein that exhibited potent cytotoxicity against human leukemic T-cells was cloned from the Bacillus thuringiensis TK-E6 strain. The protein, designated as parasporin-2Ab (PS2Ab), was a polypeptide of 304 amino acid residues with a predicted molecular weight of 33,017. The deduced amino acid sequence of PS2Ab showed significant homology (84% identitiy) to parasporin-2Aa (PS2Aa) from the B. thuringiensis A1547 strain. Upon processing of PS2Ab with proteinase K, the active form of 29 kDa was produced. The activated PS2Ab showed potent cytotoxicity against MOLT-4 and Jurkat cells and the EC50 values were estimated as 0.545 and 0.745 ng/mL, respectively. The cytotoxicity of PS2Ab was significantly higher than that of PS2Aa reported elsewhere. Although both cytotoxins were structurally related, it was thought that the minor differences found were responsible for the different cytotoxicities of PS2Ab and PS2Aa.

Original languageEnglish
Pages (from-to)278-283
Number of pages6
JournalCurrent Microbiology
Issue number4
Publication statusPublished - Oct 1 2007

ASJC Scopus subject areas

  • Microbiology
  • Applied Microbiology and Biotechnology


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