Condensed phylogenetic tree for single domain GRXs from UNIPROT database. Panel A: Global tree. The outgroup on the lower left of the tree is composed of TRX single domain proteins (in yellow). All major divisions between clusters have bootstrap values of 100%, indicated by the "100" label. The CGFS class of GRXs is depicted on the upper branchs [in green]. Sequences are more homogeneous on this class. The mid-lower branches depict CPYC class GRXs [in mauve]. There is a wider variability in the sequences of this class. The clusters identified with the tag "Bacteria*" include almost all non-proteobacteria GRX domains. These include domains from Actinobacteria, Deinnococcus, Planktomycetes, Green sulfur bacteria, Green non sulfur bacteria, Thermotoga, Aquifaceae, and Flavobacteria. The cluster identified with the tag "Bacteria**" include mostly proteobacteria GRX domains. GRX domains from Cyanobacteria and Spirochaetes are also present in this cluster. Panel B: Condensed phylogenetic tree of single domain GRXs in archaea. Panel C: Phylogenetic tree of GRX proteins for bacteria. CGFS class GRXs [Cluster 1] have less variability in their sequence than CPYC class GRXs [other clusters]. Some GRX-like proteins have lost their active site [XXXX in Cluster 2]. Panel D: Phylogenetic tree of GRX proteins for eukaryotes. CGFS GRXs [in green] have less variability in their sequence than CPYC GRXS [in mauve]. Nevertheless, the variability in the sequence of the active site for CGFS GRXs is far greater than that found in bacteria [compare to panel C].