胞质Ca2+通过从包涵体中释放来调节大肠杆菌中的蛋白质表达。
Cytosolic Ca2+ regulates protein expression in E. coli through release from inclusion bodies.
作者信息
Naseem Riffat, Davies Sally Rosser, Jones Helen, Wann Kenneth T, Holland I Barry, Campbell Anthony K
机构信息
Department of Medical Biochemistry and Immunology, Tenovus building, Cardiff University, Heath Park, Cardiff CF14 XN, UK.
出版信息
Biochem Biophys Res Commun. 2007 Aug 17;360(1):33-9. doi: 10.1016/j.bbrc.2007.05.223. Epub 2007 Jun 14.
The results here are the first clear demonstration of a physiological role for cytosolic Ca(2+) in Escherichia coli by releasing a Ca(2+) binding protein, apoaequorin, from inclusion bodies. In growth medium LB the cytosolic free Ca(2+) was 0.1-0.3 microM. Addition of EGTA reduced this to <0.1 microM, whereas addition of Ca(2+) (10mM) resulted in a cytosolic free Ca(2+) of 1-2 microM for at least 2h. Ca(2+) caused a 1.5- to 2-fold increase in the level of apoaequorin induced by IPTG. Whereas EGTA induced a 50% decrease. The effect of a Ca(2+) was explained by release of protein from the inclusion bodies, together with a stabilisation of apoaequorin against degradation. Ca(2+) also reduced the generation time by 4-5 min. These results have important implications for unravelling the physiological role of cytosolic Ca(2+) in bacteria, particularly where several species are competing for the same nutrients, such as in the gut.
通过从包涵体中释放钙结合蛋白脱辅基水母发光蛋白，此处的结果首次明确证明了大肠杆菌胞质中Ca(2+)的生理作用。在LB生长培养基中，胞质游离Ca(2+)为0.1 - 0.3微摩尔。添加乙二醇双四乙酸（EGTA）可将其降至<0.1微摩尔，而添加Ca(2+)（10毫摩尔）会使胞质游离Ca(2+)在至少2小时内达到1 - 2微摩尔。Ca(2+)使异丙基-β-D-硫代半乳糖苷（IPTG）诱导的脱辅基水母发光蛋白水平增加了1.5至2倍。而EGTA则使其降低了50%。Ca(2+)的作用可通过蛋白从包涵体中的释放以及脱辅基水母发光蛋白抗降解的稳定性来解释。Ca(2+)还使代时缩短了4 - 5分钟。这些结果对于阐明细菌胞质中Ca(2+)的生理作用具有重要意义，特别是在几种物种争夺相同营养物质的情况下，如在肠道中。
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