title: Transport of glucose and mannose by a common phosphoenolpyruvate-dependent phosphotransferase system in Streptococcus mutans GS5.
abstract: Decryptified cells of Streptococcus mutans GS5 transport glucose, mannose, and fructose by constitutive phosphoenolpyruvate-dependent phosphotransferase systems (PTSs). Although the non-metabolizable glucose analog 2-deoxyglucose is transported by a PTS, alpha-methylglucose is not taken up by strain GS5. The transport of [14C]mannose and [14C]glucose was almost totally blocked by the heterologous sugars, indicating that these substrates may share a common PTS permease. [14C]fructose transport, however, was not inhibited by large excesses of glucose, indicating the existence of a separate fructose PTS. All "tight" glucose PTS- mutant clones studied were also unable to transport mannose, whereas some "leaky" glucose PTS- clones also were leaky for mannose phosphorylation. Fructose transport in most of these mutant strains was unimpaired, indicating that genetic lesions did not involve soluble (cytoplasmic) PTS components.
mesh_terms: D001667:Binding, Competitive; D001692:Biological Transport; D005632:Fructose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D008358:Mannose / Q000378:metabolism*; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000378:metabolism*; D013295:Streptococcus mutans / Q000235:genetics / Q000378:metabolism*
chemical_list: D005632:Fructose; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; D005947:Glucose; D008358:Mannose