Figure 2.
The mel operon structure and MelB involvement in galactinol, melibiose, and RFO consumption. a, atu4660-atu4665 genes belong to the same transcription unit (operon prediction by Westover et al. (22) that we called the mel operon). The mel promoter Pmel indicates the gene transcription direction. Both atu4660 and atu4665 genes are annotated as two α-galactosidases, atu4661 as the PBP MelB and atu4662-atu4664 genes as the associated ABC transporter. Comparison is between the mel operon genes and their homologues in E. meliloti 1021 (13, 14). the percentages of sequence identity between each homologous protein are indicated; for example, the PBPs AgpA and MelB share 73% sequence identity. b, 2.5 days growth (A at 600 nm) of A. fabrum C58 WT strain (in white) and the C58ΔmelB mutant (in black) in AT minimal medium supplemented with different carbon sources. Standard deviations were calculated from five technical and two biological replicates. Asterisks indicated significant differences (Mann-Whitney p value = 0.05).