枯草芽孢杆菌中一个受二硫键还原剂诱导并与伸长因子Tu同源的蛋白质

IDENTIFICATION OF A SULFHYDRYL-REDUCING AGENTINDUCIBLE PROTEIN HIGHLY HOMOLOGOUS TO PROTEIN SYNTHESIS ELONGATION FACTOR Tu IN BACILLUS SUBTILIS

分析了β-巯基乙醇（β-ME）和二硫苏糖醇（DTT）对枯草芽孢杆菌（Bacillussubtilis细胞蛋白质组分的影响。在LB培养基中，β-ME和DTT处理能诱导一个50kD蛋白质（P50）的合成。在正常生长条件下P50是一个组成性（constitutive）成的细胞质蛋白质。热激也能诱寻P50，但是孢子形成（sporulation）不能诱导P50。在Schaeffer孢子形成培养基中，β-ME和DTT都不能诱导P5O，表明二硫键还原剂诱导P50的能力依赖于特定的生理条件。用VS蛋白酶有限降解P50，得到4个主要的多肽片段，测定了其中两个片段的N-端氨基酸序列。同源性检索发现P50高度同源于蛋白质合成的伸长因子Tu。

It was examined that the effect of β-mereaptoethanol and dithiothreitoltreatments, which should affect disulfide bond formation of proteins, on cellularprotein components of Bacillus subtilis. In LB medium, the treatments induced thesynthesis of a 50kD protein (P50), which is synthesized constitutively under normalgrowth condition and is a major cytoplasmic protein. P50 was also induced by heatshock, but not by sporulation. In Schaeffer's sporulation medium, however, P50 wasnot induced by the sulfhydryl-reducing agents. This suggests that thesulfhydryl-reducing agent-inducibility of P50 might depent on specific physiologicalcondition(s). The amino terminal sequences of two of the four main V8 proteasefragments of P50 were determined. A search in databases revealed that P50 washighly homologous to protein synthesis elongation factor Tu of B. subtilis.