Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Apdo. Postal 1622, Puebla, Puebla, Mexico.
Arch Microbiol. 2013 Jun;195(6):431-8. doi: 10.1007/s00203-013-0890-x. Epub 2013 Apr 28.
Gluconacetobacter diazotrophicus is a nitrogen-fixing bacterium and endophyte of sugarcane. We have cloned and sequenced the genes coding for the components of the iron ABC-type acquisition system of G. diazotrophicus. Sequence analysis revealed three ORFs, (feuA, feuB, and feuC) organized as an operon and encoding polypeptides of 346 (38 kDa), 342 (34.2 kDa), and 240 (26 kDa) amino acids, respectively. The deduced translation products of the feu operon showed similarity with a periplasmic solute-binding protein (FeuA), permease (FeuB), and ATPase (FeuC) involved in Fe transport. The role of FeuB in the survival of G. diazotrophicus under iron depletion was evaluated by comparing the ability of wild-type and FeuB-Km(R) -mutant strains in a medium without iron supplementation and in a medium containing 2, 2'-dipyridyl (DP). Growth of the mutant was affected in the medium containing DP. The operon was expressed at higher levels in cells depleted for iron than in those that contained the metal. A decrease in nitrogenase activity was observed with the FeuB-Km(R) -mutant strain that with the wild-type under iron deficiency conditions, suggesting that the Feu operon play role in Fe nutrition of G. diazotrophicus.
谷氨酸棒杆菌是一种固氮细菌和甘蔗内生菌。我们已经克隆和测序了编码谷氨酸棒杆菌铁 ABC 型摄取系统成分的基因。序列分析显示，有三个 ORF（feuA、feuB 和 feuC）组织成一个操纵子，并分别编码 346（38 kDa）、342（34.2 kDa）和 240（26 kDa）氨基酸的多肽。feu 操纵子的推断翻译产物与涉及 Fe 转运的周质溶质结合蛋白（FeuA）、渗透酶（FeuB）和 ATP 酶（FeuC）具有相似性。通过比较无铁补充培养基和含有 2,2'-二吡啶（DP）的培养基中野生型和 FeuB-Km(R)-突变株的生存能力，评估了 FeuB 在铁耗竭下谷氨酸棒杆菌存活中的作用。突变株在含有 DP 的培养基中的生长受到影响。与含有金属的细胞相比，在缺铁的细胞中，操纵子的表达水平更高。在缺铁条件下，与野生型相比，氮酶活性下降表明 Feu 操纵子在谷氨酸棒杆菌的铁营养中起作用。
