Tichi Mary A, Tabita F Robert
Department of Microbiology and Plant Molecular Biology/Biotechnology Program, The Ohio State University, Columbus, Ohio 43210-1292, USA.
J Bacteriol. 2002 Apr;184(7):1905-15. doi: 10.1128/JB.184.7.1905-1915.2002.
Various mutant strains were used to examine the regulation and metabolic control of the Calvin-Benson-Bassham (CBB) reductive pentose phosphate pathway in Rhodobacter capsulatus. Previously, a ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO)-deficient strain (strain SBI/II) was found to show enhanced levels of cbb(I) and cbb(II) promoter activities during photoheterotrophic growth in the presence of dimethyl sulfoxide. With this strain as the starting point, additional mutations were made in genes encoding phosphoribulokinase and transketolase and in the gene encoding the LysR-type transcriptional activator, CbbR(II). These strains revealed that a product generated by phosphoribulokinase was involved in control of CbbR-mediated cbb gene expression in SBI/II. Additionally, heterologous expression experiments indicated that Rhodobacter sphaeroides CbbR responded to the same metabolic signal in R. capsulatus SBI/II and mutant strain backgrounds.
利用各种突变菌株来研究荚膜红细菌中卡尔文-本森-巴斯姆(CBB)还原性戊糖磷酸途径的调控和代谢控制。此前,发现一种1,5-二磷酸核酮糖羧化酶/加氧酶(RubisCO)缺陷型菌株(SBI/II菌株)在存在二甲基亚砜的光异养生长过程中,cbb(I)和cbb(II)启动子活性水平增强。以该菌株为起点,在编码磷酸核糖激酶和转酮醇酶的基因以及编码LysR型转录激活因子CbbR(II)的基因中进行了额外的突变。这些菌株表明,磷酸核糖激酶产生的一种产物参与了SBI/II中CbbR介导的cbb基因表达的控制。此外,异源表达实验表明,球形红细菌CbbR在荚膜红细菌SBI/II和突变菌株背景中对相同的代谢信号作出反应。