Open AccessBinding of cycloheximide to ribosomes from wild-type and mutant strains of Saccharomyces cerevisiae
Author(s) -
Walter Stöcklein,
Wolfgang Piepersberg
Publication year - 1980
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.18.6.863
Subject(s) - cycloheximide , ribosome , eukaryotic ribosome , eukaryotic small ribosomal subunit , saccharomyces cerevisiae , eukaryotic large ribosomal subunit , ribosomal rna , biology , ribosomal protein , yeast , binding site , biochemistry , mutant , a site , binding constant , protein biosynthesis , microbiology and biotechnology , rna , gene
Cycloheximide bound to cytoplasmic (80S) ribosomes of the yeast Saccharomyces cerevisiae with an association constant (Ka) of 2.0 (+/- 0.5) x 10(7) M-1. The number of binding sites found per ribosome was between 0.4 and 0.6; it was reduced by high-salt treatment of ribosomes 60S particles prepared in the presence of high salt had a lower affinity (Ka: 5.5 [+/- 0.5] x 10(6) M-1) than did 80S ribosomes, but a greater proportion of particles (0.8) were able to bind. No specific binding to 40S subunits was observed. The addition of supernatant fractions (S100, high-salt wash fraction) increased the number of binding sites found per 80S ribosome up to 0.8, leaving the association constant unchanged. In contrast, the affinity of 60S subunits was enhanced to a Ka value of 3.5 x 10(-7) M-1 by the addition of supernatant fractions, whereas the number of binding sites stayed constant. A model to explain these facts is proposed. 80S ribosomes, as well as 60S subunits of strain cy32, which is highly resistant to cycloheximide and altered in ribosomal protein L29 (18), showed a drastically reduced affinity for the drug (Ka values of 2.0 x 10(6) M-1).