Fig. 3

Metabolism of galactose and lactose in S. thermophilus. A Schematic representation of the main steps of lactose and galactose catabolism in STH. LacEF, lactose/galactose PTS system; LacG, 6-phospho-beta-galactosidase; LacD, tagatose 1,6-biphosphate aldolase; LacC, tagatose-6-phosphate kinase; LacAB, galactose-6-phosphate isomerase subunits A and B; LacS, lactose permease; LacZ, beta-galactosidase; GalM, galactose mutarotase; LacX, aldolase 1-epimerase; GalK, galactokinase; GalT, galactose-1-phosphate uridylyltransferase; GalE, UDP-glucose 4-epimerase; PgmA, phosphoglucomutase. B Nucleotide sequences alignment of the galR-galK intergenic region of various STH strains. Promoter sequences were annotated according to Vaughan et al. (2001) and Vaillancourt et al. (2002). The start codon of both galR and galK is underlined. The − 35 and − 10 sequences are grey-boxed and the ribosome binding sites are in bold. The transcription starting sites are in red. Nucleotide substitutions and indels are yellow- and blue-boxed, respectively. Stars indicate point mutations in the galK promoter region of Gal+ mutants. 1: Promoter sequence of strains DGCC 7710, 05–34, C106, ND07, MN-BM-A02, ASCC 1275, N4L, MTH17CL396, JIM8232, CIRM-BIA1048, CIRM-BIA1049, ST109, CAG:236, CIRM-BIA1047, MTCC 5461 and CIRM-BIA772; 2: Promoter sequence of strain CIRM-BIA1121; 3: Promoter sequence of strain B59671; 4: Promoter sequence of strain TH982; 5: Promoter sequence of strain 1F8CT; 6: Promoter sequence of strains LMG 18311, BIO1488, KU30, KLDS3.1012, CIRM-BIA1125, CIRM-BIA1116, GABA, LMG S-29186, LMD-9, CIRM-BIA1051, CIRM-BIA1055, CIRM-BIA2101, CIRM-BIA67, CIRM-BIA1050, CIRM-BIA36, TH985, FAM 13496, CIRM-BIA16, IDCC2201, ACA-DC 2, CIRM-BIA18, CIRM-BIA32, CIRM-BIA1358, CIRM-BIA19, APC151, CIRM-BIA1122, MN-ZLW-002, ND03, SMQ-301, MN-BM-A01, and S9; 7: Promoter sequence of strain EPS; 8: Promoter sequence of strain CIRM-BIA65; 9: Promoter sequence of STH CNRZ1066; 10: Promoter sequence of S. thermophilus CS8; 11: Promoter sequence of strain CIRM-BIA1046; 12: Promoter sequence of strain TH1477; 13: Promoter sequence of strains CIRM-BIA23, CIRM-BIA29, CIRM-BIA30, and CIRM-BIA1035; 14: Promoter sequence of S. thermophilus KLDS SM; 15: Promoter sequence of S. thermophilus KLDS 3.1003; 16: Promoter sequence of strain ST3; 17: Promoter sequence of strain TH1436; 18: Promoter sequence of strains M17PTZA496, ATCC 19258, and NCTC12958; 19: Promoter sequence of strains JIM1081, CIRM-BIA961, CIRM-BIA967, JIM10116, and CIRM-BIA336; 20: Promoter sequence of strains CIRM-BIA368, CIRM-BIA956, and CIRM-BIA998. C Genetic organization of genes coding for the tagatose 6P pathway in strain JIM10116 and CIRM-BIA336. The lengths of genes (pentagons) and intergenic regions are drawn to scale. Blue-colored pentagons code for proteins involved in galactose/lactose assimilation. The underlined part of the cluster corresponds to the region with high nucleotide identity (> 96%) with gene clusters found in various Enterococcus and Lactococcus species