Interactions between paralogous bacterial enhancer-binding proteins enable metal-dependent regulation of alternative nitrogenases in Azotobacter vinelandii.
Interactions between paralogous bacterial enhancer-binding proteins enable metal-dependent regulation of alternative nitrogenases in Azotobacter vinelandii.
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副亲缘细菌增强子结合蛋白之间的相互作用使金属依赖性调节替代氮酶在黄氏固氮菌。
DOI：
10.1111/mmi.14955
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发表时间：
2022-07
影响因子：
3.6
通讯作者：
Dixon, Ray
中科院分区：
文献类型：
--
作者：
Appia-Ayme, Corinne;Little, Richard;Chandra, Govind;Martins, Carlo de Oliveira;Batista, Marcelo Bueno;Dixon, Ray
关键词：
到目前为止分离的所有重氮菌和古生菌都利用活性部位含有钼的固氮酶辅助因子将大气中的氮素固定为氨。然而，除了依赖钼的固氮酶外，一些固氮原核生物还表达遗传上截然不同的替代固氮酶同工酶，即依赖于V的固氮酶和仅含Fe的固氮酶。固氮酶同工酶根据金属的可获得性和催化效率分级表达。在蛋白质细菌中，这种层级结构是通过专门的细菌增强子结合蛋白(BEBPs)对基因簇进行严格的转录调控来维持的。模型固氮菌VnfA含有两个类似的钒固氮酶激活剂VnfA，命名为VnfA2和VnfA3，功能未知。在这里，我们证明了VnfA1和VnfA3的bEBPs与棕色固氮菌基因组中相同的目标启动子结合，并在缺乏V的情况下共同激活一组基因，包括只有铁的固氮酶的结构基因。共激活被V的存在所抑制，并且依赖于与VnfA3共表达的辅助蛋白VnfZ。我们的研究揭示了固氮所需的bEBPs之间的过量相互作用，揭示了微调替代固氮酶的表达以响应金属可用性的前所未有的潜力。除了使用常规的钼固氮酶来固定大气中的氮外，一些重氮菌还编码另一种固氮酶同工酶，分别命名为依赖钒的固氮酶和仅铁的固氮酶。在这里，我们揭示了一个复杂的金属依赖的调控网络，它通过细菌增强蛋白之间的相互作用来控制棕色固氮菌中替代固氮酶的分层表达，从而微调基因表达的调节。
All diazotrophic bacteria and archaea isolated so far utilise a nitrogenase enzyme‐containing molybdenum in the active site co‐factor to fix atmospheric dinitrogen to ammonia. However, in addition to the Mo‐dependent nitrogenase, some nitrogen‐fixing prokaryotes also express genetically distinct alternative nitrogenase isoenzymes, namely the V‐dependent and Fe‐only nitrogenases, respectively. Nitrogenase isoenzymes are expressed hierarchically according to metal availability and catalytic efficiency. In proteobacteria, this hierarchy is maintained via stringent transcriptional regulation of gene clusters by dedicated bacterial enhancer‐binding proteins (bEBPs). The model diazotroph Azotobacter vinelandii contains two paralogs of the vanadium nitrogenase activator VnfA (henceforth, VnfA1), designated VnfA2 and VnfA3, with unknown functions. Here we demonstrate that the VnfA1 and VnfA3 bEBPs bind to the same target promoters in the Azotobacter vinelandii genome and co‐activate a subset of genes in the absence of V, including the structural genes for the Fe‐only nitrogenase. Co‐activation is inhibited by the presence of V and is dependent on an accessory protein VnfZ that is co‐expressed with VnfA3. Our studies uncover a plethora of interactions between bEBPs required for nitrogen fixation, revealing the unprecedented potential for fine‐tuning the expression of alternative nitrogenases in response to metal availability. In addition to using the conventional molybdenum nitrogenase to fix atmospheric nitrogen, some diazotrophic bacteria encode alternative nitrogenase isoenzymes, named the vanadium‐dependent and iron‐only nitrogenases respectively. Here we uncover a complex metal‐dependent regulatory network, which controls hierarchical expression of the alternative nitrogenases in Azotobacter vinelandii, through interactions between bacterial enhancer proteins that fine‐tune regulation of gene expression.
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DOI：
10.1007/978-1-61779-194-9_6
发表时间：
2011-01-01
期刊：
NITROGEN FIXATION: METHODS AND PROTOCOLS
影响因子：
--
作者：
Dos Santos, Patricia C.
通讯作者：
Dos Santos, Patricia C.
影响因子：
3.2
作者：
FRISE, E;GREEN, A;DRUMMOND, M
通讯作者：
DRUMMOND, M
影响因子：
3.2
作者：
Hamilton, Trinity L.;Ludwig, Marcus;Peters, John W.
通讯作者：
Peters, John W.
影响因子：
48
作者：
Gibson, Daniel G.;Young, Lei;Smith, Hamilton O.
通讯作者：
Smith, Hamilton O.
DOI：
10.1111/j.1432-1033.1993.tb18003.x
发表时间：
1993-07-01
期刊：
EUROPEAN JOURNAL OF BIOCHEMISTRY
影响因子：
--
作者：
GOLLAN, U;SCHNEIDER, K;KLIPP, W
通讯作者：
KLIPP, W