A Saccharomyces cerevisiae mutant with echinocandin-resistant 1,3-beta-D-glucan synthase.

摘要: A novel, potent, semisynthetic pneumocandin, L-733,560, was used to isolate a resistant mutant in Saccharomyces cerevisiae. This compound, like other pneumocandins and echinocandins, inhibits 1,3-beta-D-glucan synthase from Candida albicans (F.A. Bouffard, R.A. Zambias, J. F. Dropinski, J.M. Balkovec, M.L. Hammond, G.K. Abruzzo, K.F. Bartizal, J.A. Marrinan, M. B. Kurtz, D.C. McFadden, K.H. Nollstadt, M.A. Powles, D.M. Schmatz, Med. Chem. 37:222-225, 1994). Glucan synthesis catalyzed by crude membrane fraction prepared the S. cerevisiae R560-1C inhibition L-733,560. The nearly 50-fold increase 50% inhibitory concentration against glucan commensurate with whole-cell resistance. cross-resistant inhibitors of C. (aculeacin A, dihydropapulacandin, others) but not compounds different modes action. Genetic analysis revealed that enzyme pneumocandin resistance due single gene, designated etg1-1 (echinocandin target gene 1), which semidominant heterozygous diploids. mutation did confer enhanced ability metabolize L-733,560 had no effect on membrane-bound enzymes chitin I squalene synthase. Alkali-soluble beta-glucan synthesized microsomes indistinguishable wild-type product. 1,3-beta-D-Glucan activity fractionated NaCl Tergitol NP-40; reconstitution fractions membranes drug is associated insoluble fraction. We propose encodes subunit complex.