Sensitivity of thermoacidophilic archaebacteria to alpha-sarcin

The protein synthesis machinery of Sulfolobus solfataricus , a thermoacidophilic archaebacterium, is insensitive to most of the known antibiotics that interfere with elongation. alpha-Sarcin, a cytotoxic protein, inhibits protein synthesis on eukaryotic systems by cleaving a specific sequence of the large rRNA. alpha-Sarcin is capable of inhibiting protein synthesis on S. solfataricus producing a fragment under conditions similar to those which produce it in yeast ribosomes. This result suggests the presence on S. solfataricus of the sequence necessary for the enzymatic hydrolysis promoted by alpha-sarcin.