FIG 1.

An amino acid alignment of the primer-binding regions. Residue numbering is based on the full-length But protein sequence from Roseburia intestinalis L1-82 GenBank accession no. EEV00989. Functionally confirmed sequences occupy the top green-bordered box. Sequences with little activity are bordered by the red box. The glycine at position 234 of this alignment is conserved in all highly active sequences. Amino acid residues are colored according to the RasMol convention. 4hbt, 4-hydroxybutyryl-CoA:acetate-CoA transferase (outgroup).