title: NMR structure of the enzyme GatB of the galactitol-specific phosphoenolpyruvate-dependent phosphotransferase system and its interaction with GatA.
abstract: The phosphoenolpyruvate-dependent carbohydrate transport system (PTS) couples uptake with phosphorylation of a variety of carbohydrates in prokaryotes. In this multienzyme complex, the enzyme II (EII), a carbohydrate-specific permease, is constituted of two cytoplasmic domains, IIA and IIB, and a transmembrane channel IIC domain. Among the five families of EIIs identified in Escherichia coli, the galactitol-specific transporter (II(gat)) belongs to the glucitol family and is structurally the least well-characterized. Here, we used nuclear magnetic resonance (NMR) spectroscopy to solve the three-dimensional structure of the IIB subunit (GatB). GatB consists of a central four-stranded parallel beta-sheet flanked by alpha-helices on both sides; the active site cysteine of GatB is located at the beginning of an unstructured loop between beta1 and alpha1 that folds into a P-loop-like structure. This structural arrangement shows similarities with other IIB subunits but also with mammalian low molecular weight protein tyrosine phosphatases (LMW PTPase) and arsenate reductase (ArsC). An NMR titration was performed to identify the GatA-interacting residues.
authors.affiliation: Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada. laurent.volpon@umontreal.ca
authors.forename: Laurent
authors.initials: L
authors.lastname: Volpon
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Young
authors.forename: Allan
authors.initials: A
authors.lastname: Matte
authors.forename: Kalle
authors.initials: K
authors.lastname: Gehring
mesh_terms: D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D004376:Galactitol / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits
chemical_list: D029968:Escherichia coli Proteins; D009097:Multienzyme Complexes; D021122:Protein Subunits; D004376:Galactitol; C515805:GatA protein, E coli; C515804:GatB protein, E coli; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System