Fig. 2: Resurrection and characterization of ancestral nitrogenases.
From: Resurrected nitrogenases recapitulate canonical N-isotope biosignatures over two billion years
a schematic of methods used to insert ancestral genes into the host A. vinelandii genome37 b Nitrogenase structure and core nif operon, visualized with Mol*64. c Root mean square deviation (RMSD) of atoms in predicted structures versus amino acid sequence identity (%). d Sequence alignment of residues within 5 Å of the FeMo-cofactor of NifD. Residue numbering is based on WT A. vinelandii NifD. e Growth curves of cultures under nitrogen-fixing conditions. A smoothed curve is shown along with the individual data points of five biological replicates per strain. f in vivo ethylene production rates, presented as log2 fold change relative to WT rates. Bars represent mean ± standard error. g In vitro specific activity of purified nitrogenases for H+, C2H2, and N2 substrates. Bars represent mean ± standard deviation.
