Anborgh P H, Parmeggiani A
CNRS, Laboratoire de Biochimie, Ecole Polytechnique, Palaiseau, France.
EMBO J. 1991 Apr;10(4):779-84. doi: 10.1002/j.1460-2075.1991.tb08009.x.
The new thiazolyl peptide antibiotic GE2270 A, isolated from Planobispora rosea strain ATCC 53773, is shown to inhibit bacterial protein biosynthesis in vitro by affecting specifically the GTP-bound form of elongation factor Tu (EF-Tu). The 'off' rate of EF-Tu.GTP is slowed down 400-fold, locking GTP on EF-Tu, whereas EF-Tu.GDP is unaffected. Therefore, on the EF-Tu.guanine nucleotide interaction, GE2270 A mimicks the effect of aa-tRNA. In line with this, the binding of aa-tRNA to EF-Tu.GTP is hindered by the antibiotic, as shown by the absence of a stable ternary complex and the inhibition of the enzymatic binding of aa-tRNA to the ribosome. This blocks the elongation cycle. GE2270 A does not essentially modify the intrinsic GTPase activity of EF-Tu, but impairs the stimulation by ribosomes of this reaction. The negative effect of GE2270 A on the EF-Tu.GTP interaction with aa-tRNA bears similarities with that of the structurally unrelated pulvomycin, whereas marked differences were found by comparing the effects of these two antibiotics on EF-Tu.GDP. This work emphasizes the varieties of the transitional conformations which tune the EF-Tu interaction with GTP and GDP.
从玫瑰双孢菌ATCC 53773菌株中分离出的新型噻唑基肽抗生素GE2270 A，在体外通过特异性影响延伸因子Tu（EF-Tu）的GTP结合形式来抑制细菌蛋白质生物合成。EF-Tu.GTP的“解离”速率减慢400倍，使GTP锁定在EF-Tu上，而EF-Tu.GDP不受影响。因此，在EF-Tu与鸟嘌呤核苷酸的相互作用上，GE2270 A模拟了氨酰-tRNA的作用。与此一致的是，如稳定三元复合物的缺失以及氨酰-tRNA与核糖体的酶促结合受到抑制所示，抗生素阻碍了氨酰-tRNA与EF-Tu.GTP的结合。这阻断了延伸循环。GE2270 A基本上不改变EF-Tu的内在GTP酶活性，但损害了核糖体对该反应的刺激作用。GE2270 A对EF-Tu.GTP与氨酰-tRNA相互作用的负面影响与结构不相关的普尔霉素相似，而通过比较这两种抗生素对EF-Tu.GDP的作用发现了明显差异。这项工作强调了调节EF-Tu与GTP和GDP相互作用的过渡构象的多样性。
