Shewanella oneidensis MR-1 shows remarkable respiratory versatility with a large variety of extracellular electron acceptors (termed extracellular electron transfer, EET). To utilize the various electron acceptors, the bacterium must employ complex regulatory mechanisms to elicit the relevant EET pathways. To investigate the relevant mechanisms, we integrated EET genes and related transcriptional factors (TFs) into transcriptional regulatory modules (TRMs) and showed that many bridge proteins in these modules were signal proteins, which generally contained one or more signal processing domains (eg, GGDEF, EAL, PAS, etc.). Since Shewanella has to respond to diverse environmental conditions despite encoding few EET-relevant TFs, the overabundant signal proteins involved in the TRMs can help decipher the mechanism by which these microbes elicit a wide range of condition-specific responses. By combining proteomic data and protein bioinformatic analysis, we demonstrated that diverse signal proteins reconciled the different EET pathways, and we discussed the functional roles of signal proteins involved in the well-known MtrCAB pathway. Additionally, we showed that the signal proteins SO_2145 and SO_1417 played central roles in triggering EET pathways in anaerobic environments. Taken together, our results suggest that signal proteins have a profound impact on the transcriptional regulation of EET genes and thus have potential applications in microbial fuel cells.

中文翻译：

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转录调节模块分析表明，桥梁蛋白调和细胞外电子转移途径中的多个信号。

沙瓦氏菌（Shewanella oneidensis）MR-1具有多种细胞外电子受体（称为细胞外电子转移，EET），显示出显着的呼吸多功能性。为了利用各种电子受体，细菌必须采用复杂的调节机制来引发相关的EET途径。为了研究相关机制，我们将EET基因和相关的转录因子（TFs）整合到转录调节模块（TRMs）中，发现这些模块中的许多桥蛋白都是信号蛋白，通常包含一个或多个信号处理域（例如，GGDEF ，EAL，PAS等）。由于Shewanella尽管编码了与EET相关的TF很少，但仍必须对各种环境条件做出响应，TRM中涉及的过量信号蛋白可以帮助破译这些微生物引发广泛的条件特异性反应的机制。通过结合蛋白质组学数据和蛋白质生物信息学分析，我们证明了多种信号蛋白可调节不同的EET途径，并且我们讨论了信号蛋白参与著名的MtrCAB途径的功能作用。此外，我们证明了信号蛋白SO_2145和SO_1417在厌氧环境中触发EET途径中起着核心作用。两者合计，我们的结果表明，信号蛋白对EET基因的转录调控具有深远的影响，因此在微生物燃料电池中具有潜在的应用。我们证明了多种信号蛋白可以调节不同的EET途径，并且我们讨论了信号蛋白参与众所周知的MtrCAB途径的功能作用。此外，我们证明了信号蛋白SO_2145和SO_1417在厌氧环境中触发EET途径中起着核心作用。两者合计，我们的结果表明，信号蛋白对EET基因的转录调控具有深远的影响，因此在微生物燃料电池中具有潜在的应用。我们证明了多种信号蛋白可以调节不同的EET途径，并且我们讨论了信号蛋白参与众所周知的MtrCAB途径的功能作用。此外，我们证明了信号蛋白SO_2145和SO_1417在厌氧环境中触发EET途径中起着核心作用。两者合计，我们的结果表明，信号蛋白对EET基因的转录调控具有深远的影响，因此在微生物燃料电池中具有潜在的应用。