A SACCHAROMYCES-CEREVISIAE MUTANT WITH ECHINOCANDIN-RESISTANT 1,3-BETA-D-GLUCAN SYNTHASE
A SACCHAROMYCES-CEREVISIAE MUTANT WITH ECHINOCANDIN-RESISTANT 1,3-BETA-D-GLUCAN SYNTHASE
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DOI：
10.1128/jb.176.18.5686-5696.1994
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发表时间：
1994-09-01
影响因子：
3.2
通讯作者：
KURTZ, MB
中科院分区：
文献类型：
--
作者：
DOUGLAS, CM;MARRINAN, JA;KURTZ, MB
一种新型强效半合成肺菌素L-733,560用于分离酿酒酵母的耐药突变体。这种化合物，像其他肺菌素和棘白菌素一样，抑制白色念珠菌的1,3- β - d -葡聚糖合成酶（F.A. Bouffard， R.A. zamdas， 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和D.M. Schmatz， J. Med. Chem. 37:22 22-225, 1994）。酿酒葡萄球菌突变体R560-1C粗膜催化合成葡聚糖具有抗L-733,560抑制作用。对葡聚糖合成酶50%的抑制浓度增加了近50倍，这与全细胞抗性的增加是相称的。R560-1C对其他白色念珠菌1,3- β - d -葡聚糖合成酶抑制剂（阿库leacin A、二氢丘疹霉素等）有交叉耐药，但对不同作用模式的化合物无交叉耐药。遗传分析表明，酶和全细胞耐药是由一个突变基因etgl- 1（棘白菌素靶基因1）引起的，该基因在杂合二倍体中为半显性。etgl- 1突变没有增强代谢L-733,560的能力，也没有对膜结合酶几丁质合成酶I和角鲨烯合成酶产生影响。由R560-1C粗粒体合成的碱溶性β -葡聚糖与野生型产品无明显区别。用NaCl和tergiitol NP-40分离R560-1C的1,3- β - d -葡聚糖合成酶活性；用野生型膜的组分进行重构，发现耐药性与不溶性膜组分有关。我们提出，etgl- 1突变基因编码1,3- β - d -葡聚糖合成酶复合物的一个亚基。
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, and D.M. Schmatz, J. Med. Chem. 37:222-225, 1994). Glucan synthesis catalyzed by a crude membrane fraction prepared from the S. cerevisiae mutant R560-1C was resistant to inhibition by L-733,560. The nearly 50-fold increase in the 50% inhibitory concentration against glucan synthase was commensurate with the increase in whole-cell resistance. R560-1C was cross-resistant to other inhibitors of C. albicans 1,3-beta-D-glucan synthase (aculeacin A, dihydropapulacandin, and others) but not to compounds with different modes of action. Genetic analysis revealed that enzyme and whole-cell pneumocandin resistance was due to a single mutant gene, designated etgl-l (echinocandin target gene 1), which was semidominant in heterozygous diploids. The etgl-l mutation did not confer enhanced ability to metabolize L-733,560 and had no effect on the membrane-bound enzymes chitin synthase I and squalene synthase. Alkali-soluble beta-glucan synthesized by crude microsomes from R560-1C was indistinguishable from the wild-type product. 1,3-beta-D-Glucan synthase activity from R560-1C was fractionated with NaCl and Tergitol NP-40; reconstitution with fractions from wild-type membranes revealed that drug resistance is associated with the insoluble membrane fraction. We propose that the etgl-l mutant gene encodes a subunit of the 1,3-beta-D-glucan synthase complex.