Article Figures & Data
Figures
- Fig. 1.
Effect of GM160575 on protein synthesis in intactC. albicans cells. Protein synthesis was measured as the ability to incorporate [35S]methionine into actively growing C. albicans cells. The experiments were performed as described in Materials and Methods. Time zero corresponds to the moment of compound addition. The results are the means of three independent experiments performed in duplicate. ○, control; ■, 0.2 μg of GM160575 per ml; ▴, 5 μg of phenanthroline per ml; ▾, 2.5 μg of verrucarin per ml.
- Fig. 2.
Effect of GM160575 on RNA synthesis in intactC. albicans cells. RNA synthesis was measured as the ability to incorporate [3H]uridine into actively growingC. albicans cells. The experiments were performed as described in Materials and Methods. Time zero corresponds to the moment of compound addition. Results are the means of three independent experiments performed in duplicate. ○, control; ■, 0.2 μg of GM160575 per ml; □, 0.02 μg of GM160575 per ml; ▴, 5 μg of phenanthroline per ml; ▾, 2.5 μg of verrucarin per ml.
- Fig. 3.
Effect of sordarin on Phe-tRNAPhe synthetase activity in C. albicans. The experiment was performed as described in Materials and Methods. The effect of sordarin on Phe-tRNAPhe synthetase activity (white bars) is compared with the effect of the same drug on cell-free protein synthesis activity (shaded bars).
Tables
- Table 1.
Chemical structures of the sordarin derivatives tested
- Table 2.
Effect of sordarin derivatives on the cell-free protein synthesis assay (IC50s) and on cell growth (MICs)
Compound C. albicans2005E C. glabrata2375E C. parapsilosis2372E C. krusei2374E C. neoformans2867E IC50 (μg/ml) for rabbit reticulocytes IC50 (μg/ml) MIC (μg/ml) IC50(μg/ml) MIC (μg/ml) IC50 (μg/ml) MIC (μg/ml) IC50 (μg/ml) MIC (μg/ml) IC50 (μg/ml) MIC (μg/ml) Sordarin 0.01 8.0 0.2 >125 >100 >125 >100 >125 0.06 >125 >100 GR135402 0.2 0.015 0.8 >125 >100 >125 >100 >125 0.2 0.25 >100 GM160575 0.08 <0.001 0.4 >125 >100 >125 >100 >125 0.01 0.25 >100 GM191519 <0.005 0.12 0.5 31.0 100 >125 100 >125 0.005 125 >100 GM193663 <0.005 <0.001 0.02 31.0 >100 >125 >100 >125 0.2 8.0 >100 GM211676 <0.005 0.001 0.01 8.0 100 >125 100 >125 0.12 1.0 >100 - Table 3.
Activity profiles of several protein synthesis inhibitors in cell-free systems from sordarin-sensitive and -resistantCandida species
Compound (concn [μg/ml]) % Protein synthesis activity Step inhibiteda C. albicans C. krusei C. parapsilosis Cycloheximide (1) 94 15 25 Translocation Verrucarin A (1) 5 8 7 Peptide bond formation Paromomycin (100) 20 43 24 Translocation, peptide bond formation Anisomycin (1) 41 50 36 Peptide bond formation Hygromycin (10) 51 90 67 Translocation Puromycin (10) 48 18 16 Peptide bond formation Emetine (100) 77 97 74 Unknown Fusidic acid (100) 77 100 80 Translocation Homoharringtonine (100) 23 6 15 Loading of aminoacyl-tRNA Sordarin (1) 1 100 94 ? ↵a As described previously (2).
- Table 4.
Effect of sordarin on protein synthesis in reconstituted systems generated with sordarin-sensitive and -resistantCandida species
Source of soluble factors % Remaining protein synthesis activity for the following ribosome sourcesa: C. albicans C. krusei C. parapsilosis C. albicans 4 13 5 C. krusei 79 96 100 C. parapsilosis 80 98 100 ↵a Remaining protein synthesis activity in the presence of 0.5 μg of sordarin per ml. Each percentage is calculated with respect to the activity in the absence of sordarin for each reconstituted system.
