Formation of Nitrogenase NifDK Tetramers in the Mitochondria of Saccharomyces cerevisiae.
Stefan BurénEric M YoungElizabeth A SweenyGema Lopez-TorrejónMarcel VeldhuizenChristopher A VoigtLuis Manuel RubioPublished in: ACS synthetic biology (2017)
Transferring the prokaryotic enzyme nitrogenase into a eukaryotic host with the final aim of developing N2 fixing cereal crops would revolutionize agricultural systems worldwide. Targeting it to mitochondria has potential advantages because of the organelle's high O2 consumption and the presence of bacterial-type iron-sulfur cluster biosynthetic machinery. In this study, we constructed 96 strains of Saccharomyces cerevisiae in which transcriptional units comprising nine Azotobacter vinelandii nif genes (nifHDKUSMBEN) were integrated into the genome. Two combinatorial libraries of nif gene clusters were constructed: a library of mitochondrial leading sequences consisting of 24 clusters within four subsets of nif gene expression strength, and an expression library of 72 clusters with fixed mitochondrial leading sequences and nif expression levels assigned according to factorial design. In total, 29 promoters and 18 terminators were combined to adjust nif gene expression levels. Expression and mitochondrial targeting was confirmed at the protein level as immunoblot analysis showed that Nif proteins could be efficiently accumulated in mitochondria. NifDK tetramer formation, an essential step of nitrogenase assembly, was experimentally proven both in cell-free extracts and in purified NifDK preparations. This work represents a first step toward obtaining functional nitrogenase in the mitochondria of a eukaryotic cell.
Keyphrases
- saccharomyces cerevisiae
- gene expression
- poor prognosis
- cell free
- oxidative stress
- cell death
- binding protein
- genome wide
- reactive oxygen species
- dna methylation
- endoplasmic reticulum
- cancer therapy
- escherichia coli
- long non coding rna
- genome wide identification
- cell therapy
- human health
- transcription factor
- bone marrow
- drug delivery
- heat stress