Probably participates in a plant defense mechanism. Has cytotoxic activity against a variety of drug-resistant and drug-sensitive human tumor cell lines, and against primary chronic lymphocytic leukemia cells. Has weak cytotoxic activity against primary ovarian carcinoma cells or normal lymphocytes. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. This is a cyclic peptide. Belongs to the cyclotide family. Moebius subfamily. This peptide is cyclic. The start position was chosen by similarity to OAK1 (kalata-B1) for which the DNA sequence is known.