KstDs with shorter sequences lacking the 'loop' aggregated solely into ReKstD1-like clade which contained mostly actinobacteria such as KstD from Mycobacterium spp. The AcmB-like clade was mostly composed of sequences from proteobacteria, while in the case of the AcmB2-like clade, we identified numerous members of actinobacteria and less numerous firmicutes and proteobacteria. Interestingly, the KstD2 from Mycobacterium smegmatis was classified as a phylogenetically different sequence indicating the existence of yet another phylogenetic clade that was not represented by our selection of sequences.