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A ribosomal protein is specifically recognized by saporin, a plant toxin which inhibits protein synthesis
Author(s) -
Ippoliti Rodolfo,
Lendaro Eugenio,
Bellelli Andrea,
Brunori Maurizio
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80042-f
Subject(s) - ribosome inactivating protein , saporin , ribosome , biochemistry , eukaryotic large ribosomal subunit , ribosomal rna , ribosomal protein , biology , protein subunit , eukaryotic ribosome , a site , yeast , rna , binding site , microbiology and biotechnology , immunotoxin , gene , in vitro , cytotoxicity
Many plants express enzymes which specifically remove an adenine residue from the skeleton of the 28 S RNA in the major subunit of the eukaryotic ribosome (ribosome inactivating proteins, RIPs). The site of action of RIPs (A4324 in the rRNA from rat liver) is in a loop structure whose nucleotide sequence all around the target adenine is also conserved in those species which are completely or partially insensitive to RIPs. In this paper we identify a covalent complex between saporin (the RIP extracted from Saponaria officinalis ) and ribosomal proteins from yeast ( Saccharomyces cerevisiae ), by means of chemical crosslinking and immunological or avidin‐biotin detection. The main complex (mol. wt. ≈ 60 kDa) is formed only with a protein from the 60 S subunit of yeast ribosomes, and is not detected with ribosomes from E. coli , a resistant species. This observation supports the hypotesis for a molecular recognition mechanism involving one or more ribosomal proteins, which could provide a ‘receptor’ site for the toxin and favour optimal binding of the target adenine A4324 to the active site of the RIP.