由Tet(O)介导的核糖体对四环素的保护作用：Tet(O)与核糖体的相互作用是GTP依赖性的。

Ribosomal protection from tetracycline mediated by Tet(O): Tet(O) interaction with ribosomes is GTP-dependent.

作者信息

Trieber C A, Burkhardt N, Nierhaus K H, Taylor D E

机构信息

Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada.

出版信息

Biol Chem. 1998 Jul;379(7):847-55. doi: 10.1515/bchm.1998.379.7.847.

DOI:10.1515/bchm.1998.379.7.847

PMID:9705148

Abstract

Tet(O) mediates tetracycline resistance by protecting the ribosome from inhibition. A recombinant Tet(O) protein with a histidine tag was purified and its activity in protein synthesis characterized. Tetracycline inhibited the rate of poly(Phe) synthesis, producing short peptide chains. Tet(O)-His was able to restore the elongation rate and processivity. 70S ribosomes bound tetracycline with high affinity. Tet(O)-His in the presence of GTP, but not GDP or GMP, reduced the affinity of the ribosomes for tetracycline. Non-hydrolyzable GTP analogs in the presence of the factor were also able to interfere with tetracycline binding. Ribosomes increased the affinity of Tet(O)-His for GTPgammaS. Tet(O), 70S ribosomes and GTPgammaS formed a complex that could be isolated by gel filtration. The GTP conformer is the active form of Tet(O) that interacts with the ribosome. GTP binding is necessary for Tet(O) activity.

摘要

Tet(O) 通过保护核糖体免受抑制来介导四环素抗性。纯化了带有组氨酸标签的重组 Tet(O) 蛋白，并对其在蛋白质合成中的活性进行了表征。四环素抑制了聚（苯丙氨酸）的合成速率，产生了短肽链。Tet(O)-His 能够恢复延伸速率和持续合成能力。70S 核糖体与四环素具有高亲和力。在 GTP 存在下但不是 GDP 或 GMP 存在下的 Tet(O)-His 降低了核糖体对四环素的亲和力。在该因子存在下的不可水解 GTP 类似物也能够干扰四环素结合。核糖体增加了 Tet(O)-His 对 GTPγS 的亲和力。Tet(O)、70S 核糖体和 GTPγS 形成了一个可以通过凝胶过滤分离的复合物。GTP 构象体是与核糖体相互作用的 Tet(O) 的活性形式。GTP 结合是 Tet(O) 活性所必需的。