Alignment of GlyR1, GlyR2, GlyR3, and LacI. The putative DNA-binding domain of GlyR3 is underlined, and the putative sugar-binding domain is in bold type. Asterisks indicate identical residues, colons indicate conserved residues, and single dots indicate semiconserved residues, according to the convention of the European Bioinformatics Institute (www.ebi.ac.uk/clustalw). GenBank accession numbers for the sequences are as follows: ZP_00509723 (GlyR1), ZP_00503684 (GlyR2), and ZP_00504673 (GlyR3).