Blumenthal T, Douglass J, Smith D
Proc Natl Acad Sci U S A. 1977 Aug;74(8):3264-7. doi: 10.1073/pnas.74.8.3264.
Alterations of the structure of EF-Tu have been investigated by using the rate of EF-Tu cleavage by trypsin as a conformational probe. The presence of EF-Ts bound to EF-Tu results in a 10-fold increase in the cleavage rate. The antibiotic kirromycin, which inhibits protein synthesis by virtue of its interaction with EF-Tu, mimics this effect of EF-Ts. Both kirromycin and EF-Ts also facilitate the exchange of free GDP with GDP bound to EF-Tu. The results suggest that EF-Ts and kirromycin induce a similar conformational change in EF-Tu, thereby "opening" the guanine nucleotide binding site. The trypsin-cleaved EF-Tu still can bind GDP and EF-Ts and can function in Qbeta replicase, but it no longer spontaneously renatures following denaturation in urea.
通过使用胰蛋白酶切割EF-Tu的速率作为构象探针，对EF-Tu的结构改变进行了研究。与EF-Tu结合的EF-Ts的存在导致切割速率增加10倍。抗生素奇霉素通过与EF-Tu相互作用抑制蛋白质合成，模拟了EF-Ts的这种作用。奇霉素和EF-Ts都还促进游离GDP与结合在EF-Tu上的GDP的交换。结果表明，EF-Ts和奇霉素在EF-Tu中诱导了类似的构象变化，从而“打开”了鸟嘌呤核苷酸结合位点。经胰蛋白酶切割的EF-Tu仍然可以结合GDP和EF-Ts，并能在Qβ复制酶中发挥作用，但在尿素中变性后它不再能自发复性。
