title: Cross-talk between the L-sorbose and D-sorbitol (D-glucitol) metabolic pathways in Lactobacillus casei.
abstract: A gene encoding sorbitol-6-phosphate dehydrogenase (SorF) belonging to the sorbose operon (sorFABCDG) has been characterized in Lactobacillus casei. Inactivation of this gene revealed the presence of another sorbitol-6-phosphate dehydrogenase that was induced by D-sorbitol (D-glucitol). The gene encoding this activity (gutF) has also been isolated, sequenced and disrupted. The sorbitol-6-phosphate dehydrogenase genes (sorF, gutF) were required for growth on L-sorbose and D-sorbitol, respectively. Biochemical and transcriptional analyses of the wild-type and mutant strains demonstrated that L-sorbose and D-sorbitol induced sorF and the gene encoding the sorbose operon activator (sorR), while the expression of gutF was only activated by D-sorbitol. Furthermore, these studies indirectly suggested that a common metabolite of the L-sorbose and D-sorbitol metabolic pathways (probably D-sorbitol 6-phosphate) would act as the effector of SorR. The same effector would also be the inducer of gutF, although the two pathways seem to be subject to distinct regulatory mechanisms.
authors.affiliation: Departamento de Biotecnologı́a, Instituto de Agroquı́mica y Tecnologı́a de Alimentos, CSIC, Apdo. Correos 73, 46100 Burjassot, Spain1.
authors.forename: Marı A J
authors.initials: MAJ
authors.lastname: Yebra
authors.affiliation: Departamento de Biotecnologı́a, Instituto de Agroquı́mica y Tecnologı́a de Alimentos, CSIC, Apdo. Correos 73, 46100 Burjassot, Spain1.
authors.forename: Gaspar
authors.initials: G
authors.lastname: Pérez-Martı Nez
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D015964:Gene Expression Regulation, Bacterial; D007780:Lacticaseibacillus casei / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D008969:Molecular Sequence Data; D013012:Sorbitol / Q000378:metabolism*; D013013:Sorbose / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D013012:Sorbitol; D013013:Sorbose