Disease relevance of lacS

• The lacS gene also appears similar to the partially sequenced lactose transport gene of Lactobacillus bulgaricus (lacL; greater than 60% similarity) [1].
• The gene responsible for the transport of lactose into Streptococcus thermophilus (lacS) was cloned in Escherichia coli as a 4.2-kilobase fragment from an EcoRI library of chromosomal DNA by using the vector pKK223-3 [1].
• Little homology was found between the lactose permease of L. bulgaricus and E. coli, but the residues which are involved in the binding and the transport of lactose are conserved [2].

High impact information on lacS

• Lactose transport is affected by the phosphorylation state of HPr through changes in the activity of the LacS protein as well as expression of the lacS gene [3].
• The link between transport capacity and lacS expression levels and LacS phosphorylation are discussed [3].
• The role of the LacS protein was confirmed by uptake assays in which substantial uptake of radiolabeled lactose or galactose was observed with L. lactis or S. thermophilus plasmids harboring an intact lacS gene [4].
• The lacS gene was cloned in an E. coli-Streptococcus shuttle vector and was expressed both in a lacS deletion derivative of S. thermophilus and in a pNZ63-cured strain, L. lactis NZ6091 [4].
• The lacS gene was separated from the downstream beta-galactosidase genes (lacLM) by 2 kb of DNA containing an IS3-like insertion sequence, which is a novel arrangement for lac genes in comparison with that in other lactic acid bacteria [4].

Chemical compound and disease context of lacS

• The first 460 amino acids of the lactose permease shows homology to the melibiose transport protein of E. coli [2].

Biological context of lacS

• The nucleotide sequence of lacS and 200 to 300 bases of 3' and 5' flanking regions were determined [1].
• One of these ORFs codes for the lactose permease gene, and the other codes for the beta-galactosidase gene [2].

References