FIGURE 3.
Hydrogenase gene clusters of bacterial and archaeal representatives. Only the gene clusters containing the structural genes for the large and small subunit of the [NiFe]-hydrogenases and the corresponding maturation proteins are shown. According to the classification of Sondergaard et al. (2016) the [NiFe]-hydrogenases of N. profundicola, H. crunogenus, and D. vulgaris belong to group 1b, that of A. aeolicus to group 1d and that of G. acetivorans to group 1k (cf. Figure 2). Genes are pictured as arrows in the direction of transcription. Arrows of the same color indicate the same function of the encoded protein as explained by the key legend. Gene (and protein) abbreviations follow the respective annotations in the publicly available databases.