Structure based sequence alignment of MAT from different domains of life. Shown are Tk MAT, Ss MAT (PDB-ID 4HPV), Ec MAT (PDB-ID 1RG9) and Hs MAT (PDB-ID 2P02). Similar amino acids are highlighted with shades of blue. Active site residues are marked as follows: catalytic histidine (A), π-π-interaction (π), stabilisation of ribose hydroxyls (R), hydrophobic interaction (H), stabilisation of carbonyl (c [Ec MAT, Hs MAT], C [Tk MAT, Ss MAT]), interaction with adenine amino group (n [Ec MAT, Hs MAT], N [Tk MAT, Ss MAT]). Secondary structure elements for Tk MAT are shown under the sequence alignment (rounded rectangles: α-helices; arrows: β-strands; grey β-strands are only present in archaeal MATs). Domains:- N-terminal: red; central: blue; C-terminal: cyan; flexible helix: orange (the extension of the flexible helix differs slightly in the single MATs, the core region is delimited by the unbroken line). The alignment was prepared using STRAP (Interactive Structure based Sequence Alignment Program;
http://www.bioinformatics.org/strap/) and annotated using Jalview (http://www.jalview.org).