PUL ID

PUL0399

PubMed

22006318, Proc Natl Acad Sci U S A. 2011 Oct 25;108(43):17785-90. doi: 10.1073/pnas.1114152108. Epub 2011 Oct 17.

Characterization method

microarray

Genomic accession number

CP000033.3

Nucelotide position range

1437361-1453914

Substrate

beta-galactooligosaccharide

Loci

LBA1457-LBA1469

Species

Lactobacillus acidophilus/1579

Degradation or Biosynthesis

degradation

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

galM 1 - 987 (-) CDS No
galT 989 - 2452 (-) CDS No
galK 2472 - 3635 (-) CDS No
- 3852 - 4871 (-) CDS No
- 5036 - 5665 (-) CDS No
lacZ 5787 - 7790 (-) CAZyme: GH42 Yes
lacS 7801 - 9720 (-) TC: gnl|TC-DB|P43466|2.A.2.2.2 Yes
- 9917 - 11074 (-) other Yes
lacR 11427 - 12434 (-) TF: DBD-Pfam|LacI,DBD-SUPERFAMILY|0044558 Yes
lacL 12660 - 14546 (+) CAZyme: GH2 Yes
lacM 14530 - 15480 (+) CDS No
galE 15562 - 16554 (+) CDS No

PUL ID

PUL0399

PubMed

22006318, Proc Natl Acad Sci U S A. 2011 Oct 25;108(43):17785-90. doi: 10.1073/pnas.1114152108. Epub 2011 Oct 17.

Title

Transcriptional and functional analysis of galactooligosaccharide uptake by lacS in Lactobacillus acidophilus.

Author

Andersen JM, Barrangou R, Abou Hachem M, Lahtinen S, Goh YJ, Svensson B, Klaenhammer TR

Abstract

Probiotic microbes rely on their ability to survive in the gastrointestinal tract, adhere to mucosal surfaces, and metabolize available energy sources from dietary compounds, including prebiotics. Genome sequencing projects have proposed models for understanding prebiotic catabolism, but mechanisms remain to be elucidated for many prebiotic substrates. Although beta-galactooligosaccharides (GOS) are documented prebiotic compounds, little is known about their utilization by lactobacilli. This study aimed to identify genetic loci in Lactobacillus acidophilus NCFM responsible for the transport and catabolism of GOS. Whole-genome oligonucleotide microarrays were used to survey the differential global transcriptome during logarithmic growth of L. acidophilus NCFM using GOS or glucose as a sole source of carbohydrate. Within the 16.6-kbp gal-lac gene cluster, lacS, a galactoside-pentose-hexuronide permease-encoding gene, was up-regulated 5.1-fold in the presence of GOS. In addition, two beta-galactosidases, LacA and LacLM, and enzymes in the Leloir pathway were also encoded by genes within this locus and up-regulated by GOS stimulation. Generation of a lacS-deficient mutant enabled phenotypic confirmation of the functional LacS permease not only for the utilization of lactose and GOS but also lactitol, suggesting a prominent role of LacS in the metabolism of a broad range of prebiotic beta-galactosides, known to selectively modulate the beneficial gut microbiota.