Multiple sequence alignment of SAM decarboxylases. Sequences are denoted by gene and species name. A: Decarboxylase alignment – the residues underlined on the top line are those involved in SAM-binding, enzyme self-processing, and catalysis. Residues are highlighted according to the amino acid properties with designations as in Figure 2. B: Superimposition of the conserved residues in SAMdc from T. maritima (PDB structure 1TLU), human (PDB structure 1I7B) and potato (PDB structure 1MHM) are shown on cartoon representation of T. maritima structure (gray). Blue – Ser; Red – Ser and Ser converted into pyruvoyl group (or pyruvoyl group with covalently bound S-adenosylmethionine methyl ester); Orange – His; Cyan – Cys.