A Guanidine-Degrading Enzyme Controls Genomic Stability of Ethylene-Producing Cyanobacteria

Bo Wang, Yao Xu, Xin Wang, Joshua Yuan, Carl Johnson, Jamey Young, Jianping Yu

Research output: Contribution to journalArticlepeer-review

15 Scopus Citations


Recent studies have revealed the prevalence and biological significance of guanidine metabolism in nature. However, the metabolic pathways used by microbes to degrade guanidine or mitigate its toxicity have not been widely studied. Here, via comparative proteomics and subsequent experimental validation, we demonstrate that Sll1077, previously annotated as an agmatinase enzyme in the model cyanobacterium Synechocystis sp. PCC 6803, is more likely a guanidinase as it can break down guanidine rather than agmatine into urea and ammonium. The model cyanobacterium Synechococcus elongatus PCC 7942 strain engineered to express the bacterial ethylene-forming enzyme (EFE) exhibits unstable ethylene production due to toxicity and genomic instability induced by accumulation of the EFE-byproduct guanidine. Co-expression of EFE and Sll1077 significantly enhances genomic stability and enables the resulting strain to achieve sustained high-level ethylene production. These findings expand our knowledge of natural guanidine degradation pathways and demonstrate their biotechnological application to support ethylene bioproduction.

Original languageAmerican English
Article numberArticle No. 5150
Number of pages13
JournalNature Communications
Issue number1
StatePublished - 1 Dec 2021

Bibliographical note

Publisher Copyright:
© 2021, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.

NREL Publication Number

  • NREL/JA-2700-79641


  • ammonia
  • cyanobacteria
  • ethylene
  • guanidine
  • urea


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