Phylograms and putative remnant bacterial SECIS-like structures in two Cys-containing sequences evolved from Sec-containing homologs. In the phylograms, organisms containing the Sec-containing sequences are shown in red, and organisms containing the Cys-containing homologs are shown in blue. In the bacterial SECIS-like structures, codons for Cys are shown in green and the conserved G in the apical loop is shown in red. (a) Mannheimia succiniciproducens FdhA. (b) Desulfitobacterium hafniense HesB-like protein. C, Cys-containing; SECIS, selenocysteine insertion sequence; U, Sec-containing.