F. Sasse et al., Tubulysins, new cytostatic peptides from myxobacteria acting on microtubuli - Production, isolation, physico-chemical and biological properties, J ANTIBIOT, 53(9), 2000, pp. 879-885
New cytostatic compounds, tubulysins, were isolated from the culture broth
of strains of the myxobacteria Archangium gephyra and Angiococcus disciform
is. The compounds are peptides partly consisting of unusual amino acids and
are distantly related to the dolastatins. The tubulysins were not active a
gainst bacteria and only little against fungi, but showed high cytostatic a
ctivity against mammalian cell lines with IC50 values in the picomolar rang
e. An incubation with 50 ng/ml tubulysin A led to a complete disappearance
of the microtubuli network of the cells within 24 hours. The more active tu
bulysin D induced multipolar spindles: At 0.5 ng/ml all mitotic cells showe
d more than four spindle poles.