FIGURE 5.

The correlation between the lac repressor and the β-galactosidase allolactose synthesis motif in microbial genomes. The figure shows part of a larger tree of repressor sequences, restricted to the one branch of the tree where lac repressors were identified. A node label colored purple and preceded by a + symbol indicates that a β-galactosidase containing an allolactose synthesis motif was identified in the same genome. The node labels indicate genus, species, and repressor sequence accession number. Motif lists the residues that align with E. coli lac repressor residues in the order 79, 125, 149, 161, 193, 293, and 296. Those residues that are conserved with the E. coli protein are capitalized. Identity indicates the total number of the seven residues that are conserved with the E. coli lac repressor. The complete version of this tree shown in supplemental Fig. 2B, but note in this figure the node labels were colored by different criteria.