Ferrous iron transport protein B gene (feoB1) plays an accessory role in magnetosome formation in Magnetospirillum gryphiswaldense strain MSR-1
Ferrous iron transport protein B gene (feoB1) plays an accessory role in magnetosome formation in Magnetospirillum gryphiswaldense strain MSR-1
复制标题
亚铁转运蛋白 B 基因 (feoB1) 在 Magnetospirillum gryphiswaldense 菌株 MSR-1 的磁小体形成中起辅助作用
DOI：
10.1016/j.resmic.2008.06.005
复制
发表时间：
2008-09-01
影响因子：
2.6
通讯作者：
Li, Jilun
中科院分区：
文献类型：
--
作者：
Rong, Chengbo;Huang, Yijun;Li, Jilun
为研究亚铁转运系统在磁小体形成中的作用，从趋磁细菌Gryphiswaldense菌株MSR-1中克隆了编码704个氨基酸的FeoB蛋白基因（feoB 1）。feoB 1与feoA 1构成一个假定的操纵子，两个基因之间的间隔为36个碱基对。构建了一个feoB 1缺陷型突变体（Delta feoB 1），并与野生型在铁吸收、铁含量和功能互补方面进行了比较。野生型的亚铁和三价铁的摄取分别是Delta feoB 1突变体的1.8倍和1.3倍。铁含量（w/w）的三角洲feoB 1突变体的细胞外铁浓度（亚铁或柠檬酸铁）增加，只有轻微的提高。而野生型的铁含量随着细胞外铁浓度从20 PM上升到80 PM而增加约2倍。透射电子显微镜显示，三角洲feoB 1细胞生长与亚铁或柠檬酸铁产生较少的磁小体，直径较小，与野生型细胞相比。FeoAB 1启动子-lacZ转录融合体的分析表明，当MSR-1细胞在富铁条件下生长时，FeoB 1推定操纵子下调。磁小体的形成减少，但没有取消的feoB 1突变体，表明FeoB 1蛋白在这一过程中起着重要的作用。推测其他铁转运系统参与MSR-1的铁摄取。(C)2009年Elsevier Masson SAS。All rights reserved.
To investigate the role of ferrous iron transport (Feo) systems in magnetosome formation, the gene for protein FeoB (feoB1), encoding 704 amino acids, was cloned front magnetotactic bacterium Magnetospirillum gryphiswaldense strain MSR-1. feoB1 constitutes a putative operon with feoA1, and the interval between the two genes is 36 base pairs. A feoB1-deficient mutant (Delta feoB1) was constructed, and compared with wild-type in terms of iron uptake, iron content and functional complementation. Ferrous iron and ferric iron uptake in wild-type were respectively 1.8-fold and 1.3-fold higher than in the Delta feoB1 mutant. Iron content (w/w) of Delta feoB1 mutant was enhanced only slightly as extracellular iron concentration (either ferrous or ferric citrate) increased. whereas iron content of wild-type increased about 2-fold as extracellular iron concentration rose from 20 to 80 PM. Transmission electron microscopy revealed that Delta feoB1 cells grown with either ferrous or ferric citrate produced fewer magnetosomes, with smaller diameter, compared to wild-type cells. Assay of feoAB1 promoter-lacZ transcriptional fusions indicated that FeoB1 Putative operon was downregulated when MSR-1 cells were grown under iron-rich condition. Magnetosome formation was reduced but not abolished in the feoB1 mutant, indicating that FeoB 1 protein plays a significant role in this process. Other iron transport systems are presumed to be involved in iron uptake in MSR-1. (C) 2009 Elsevier Masson SAS. All rights reserved.