Enhanced H2 production by deletion of the Tfx family DNA-binding protein in the hyperthermophilic archaeon Thermococcus onnurineus NA1

A gene encoding an archaeal transcription regulator (TON_1525) homologous to the Tfx family DNA-binding protein has been identified to affect gene expression of carbon monoxide metabolism in the hyperthermophilic archaeon Thermococcus onnurineus NA1. To broadly understand gene regulation by the TON_1525 gene, a gene deletion mutant (D1525) was constructed and transcriptome changes were investigated. A total of 351 genes were found to be differentially expressed in the D1525 mutant. The expression levels of the hydrogenase genes were significantly changed; mbh (membrane-bound hydrogenase) and mch (membrane-bound carbon monoxide-dependent hydrogenase) genes were increased, and mfh2 (membrane-bound formate-dependent hydrogenase) and soluble hydrogenase genes were decreased. The D1525 mutant was cultured in a medium supplemented with maltodextrin or carbon monoxide to investigate whether changes in gene expression lead to physiological changes. The maximum H2 production rates of the D1525 mutant were significantly enhanced on both substrates compared to the wild-type strain. These results indicate that the TON_1525 gene can affect the expression of various genes including mbh and mch, consequently regulating the metabolism of T. onnurineus NA1. This study expands our understanding of the functional role of the Tfx family DNA-binding proteins. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The archaeal transcription regulator gene TON_1525 affects carbon monoxide metabolism in Thermococcus onnurineus NA1 by regulating the expression of various genes, including hydrogenase genes. A gene deletion mutant (D1525) showed differential expression of 351 genes, with increased expression of mbh and mch genes. The H2 production rates of D1525 mutant were significantly enhanced on maltodextrin and carbon monoxide substrates.