CHARACTERIZATION OF A NEW RIBOTOXIN GENE (C-SAR) FROM ASPERGILLUS-CLAVATUS

A new ribotoxin, c-sarcin, was isolated from a culture of Aspergillus clavatus. A full-length genomic DNA (c-sar) coding for c-sarcin was cl oned and sequenced. The deduced amino acid sequence showed a high homo logy to restrictocin and alpha-sarcin. The native toxin as well as the recombinant protein hydrolysed ribosomes and naked RNA. The genomic s tructure of the c-sar gene had an intron located between the coding se quences for secretory signal peptide and the mature protein. The intro n contained a stretch of 38 adenines. The intron sequence of c-snr was different from that of restrictocin but resembled that of alpha-sarci n. There was 34% identity between the intron of c-sarcin and alpha-sar cin, and this similarity was further increased to 83% if the stretch o f polyadenine was omitted. (C) 1997 Published by Elsevier Science Ltd.