All0809/8/7 is a DevBCA-like ABC-type efflux pump required for diazotrophic growth in Anabaena sp. PCC 7120.
All0809/8/7 is a DevBCA-like ABC-type efflux pump required for diazotrophic growth in Anabaena sp. PCC 7120.
复制标题
All0809/8/7 是鱼腥藻固氮生长所需的类似 DevBCA 的 ABC 型外排泵。
作者：
P. Staron;I. Maldener
外排泵通过革兰氏阴性细胞壁输出多种蛋白质和非蛋白质底物。对于丝状蓝藻Anabaena sp.菌株PCC 7120， atp驱动的糖脂外排泵DevBCA-TolC已被证明是将N(2)固定异囊从光合活性营养细胞分化的关键。在本研究中，描述了一个同源系统。All0809/8/7-TolC形成典型的atp驱动外排泵，如表面等离子体共振所示。这个假定的出口商也参与了重氮营养生长的鱼腥鱼sp. pcc7120。编码泵的质周膜融合蛋白的all0809突变体在没有组合氮的情况下无法生长。尽管该突变体的异囊在光镜和电子显微镜下与野生型没有区别，但它们在提供N(2)固定所需的微氧环境方面受到损害。对all0809转录本的RT-PCR和All0807-GFP的定位研究表明，all0809 /8/7在异泡成熟过程中最初下调，在异泡形成后期上调。外排泵的底物不能在ATP水解实验中被确定。我们讨论了All0809/8/7-TolC在维持外周质连续性中的作用，以及这对异囊分化的特殊重要性。
Efflux pumps export a wide variety of proteinaceous and non-proteinaceous substrates across the Gram-negative cell wall. For the filamentous cyanobacterium Anabaena sp. strain PCC 7120, the ATP-driven glycolipid efflux pump DevBCA-TolC has been shown to be crucial for the differentiation of N(2)-fixing heterocysts from photosynthetically active vegetative cells. In this study, a homologous system was described. All0809/8/7-TolC form a typical ATP-driven efflux pump as shown by surface plasmon resonance. This putative exporter is also involved in diazotrophic growth of Anabaena sp. PCC 7120. A mutant in all0809 encoding the periplasmic membrane fusion protein of the pump was not able to grow without combined nitrogen. Although heterocysts of this mutant were not distinguishable from those of the wild-type in light and electron micrographs, they were impaired in providing the microoxic environment necessary for N(2) fixation. RT-PCR of all0809 transcripts and localization studies on All0807-GFP revealed that All0809/8/7 was initially downregulated during heterocyst maturation and upregulated at later stages of heterocyst formation in all cells of the filament. A substrate of the efflux pump could not be identified in ATP hydrolysis assays. We discuss a role for All0809/8/7-TolC in maintaining the continuous periplasm and how this would be of special importance for heterocyst differentiation.
影响因子：
2.8
作者：
Davidson, RC;Blankenship, JR;Heitman, J
通讯作者：
Heitman, J
影响因子：
5.6
作者：
Fokina, Oleksandra;Chellamuthu, Vasuki-Ranjani;Forchhammer, Karl
通讯作者：
Forchhammer, Karl