文章基本信息

标题：Global investigation of an engineered nitrogen-fixing Escherichia coli strain reveals regulatory coupling between host and heterologous nitrogen-fixation genes
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作者：Zhimin Yang ; Yunlei Han ; Yao Ma 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2018
卷号：8
期号：1
页码：10928
DOI：10.1038/s41598-018-29204-0
语种：English
出版社：Springer Nature
摘要：Transfer of nitrogen fixation (nif) genes from diazotrophs to amenable heterologous hosts is of increasing interest to genetically engineer nitrogen fixation. However, how the non-diazotrophic host maximizes opportunities to fine-tune the acquired capacity for nitrogen fixation has not been fully explored. In this study, a global investigation of an engineered nitrogen-fixing Escherichia coli strain EN-01 harboring a heterologous nif island from Pseudomonas stutzeri was performed via transcriptomics and proteomics analyses. A total of 1156 genes and 206 discriminative proteins were found to be significantly altered when cells were incubated under nitrogen-fixation conditions. Pathways for regulation, metabolic flux and oxygen protection to nitrogenase were particularly discussed. An NtrC-dependent regulatory coupling between E. coli nitrogen regulation system and nif genes was established. Additionally, pentose phosphate pathway was proposed to serve as the primary route for glucose catabolism and energy supply to nitrogenase. Meanwhile, HPLC analysis indicated that organic acids produced by EN-01 might have negative effects on nitrogenase activity. This study provides a global view of the complex network underlying the acquired nif genes in the recombinant E. coli and also provides clues for the optimization and redesign of robust nitrogen-fixing organisms to improve nitrogenase efficiency by overcoming regulatory or metabolic obstacles.