Clustal alignment of the predicted human protein with other eukaryotic L-threonine dehydrogenase (TDH) protein sequences and 2 UDP-galactose 4-epimerase sequences (GALE). The species and the derivation of the sequences are as follows: Homo sapiens, HsTDH, genomic DNA (accession No. AC011959); HsGALE, cDNA (NP_000394); Sus scrofa, (pig), Ss, cDNA (AY095535); Mus musculus, mouse, Mm, cDNA (AY116662); Danio rerio (zebrafish), Dr, ESTs (electronic contigous sequence); Takifugu rubripes (puffer fish), Tr, genomic DNA, (AF411956); Ciona intestinalis (a tunicate), Ci, ESTs; Drosophila melanogaster, Dm, genomic DNA gene CG5955 and ESTs; Caenorhabditis elegans, Ce, genomic DNA (U64847) and ESTs; Escherichia coli, EcTDH (P07913) and EcGALE (AAC73846). The locations of the exon/exon boundaries are shown on the translated protein as underlined residues. Conserved residues are indicated by a (*), strongly similar residues by a (:) and weakly similar residues by a (.). Residues that are common to at least two protein sequences are shown in bold. The in-frame stop codon in the human sequence is indicated by a red (#). Gale protein residues in contact with the ligand nicotinamide-adenine-dinucleotide are highlighted in green and those residues in contact with the sugar ligands, uridine-5'-diphosphate-mannose and uridine-5'-diphosphate-4-deoxy-4-fluoro-alpha-d-galactose are highlighted in yellow. Those residues that have been shown to contact both NAD and sugar are highlighted in light blue [26–29].