Fig. 1. Bacterial genomes encode a protein (tadA) related to Tad2p of S.cerevisiae. Multiple sequence alignment of E.coli tadA, yeast Tad2p and putative tadA sequences from different bacteria. Residues conserved in >83% of the proteins are shown in black, similar amino acids in gray. The three putative Zn2+-chelating residues (diamond) and the glutamate thought to mediate proton transfer (bullet) are marked. The position of the point mutation (D64E) in the tadA mutant NWL37 is indicated by an asterisk. The alignment was generated with the Clustal_W software at the European Bioinformatics Institute (Thompson et al., 1994).