title: Ligand binding specificity of the Escherichia coli periplasmic histidine binding protein, HisJ.
abstract: The HisJ protein from Escherichia coli and related Gram negative bacteria is the periplasmic component of a bacterial ATP-cassette (ABC) transporter system. Together these proteins form a transmembrane complex that can take up L-histidine from the environment and translocate it into the cytosol. We have studied the specificity of HisJ for binding L-His and many related naturally occurring compounds. Our data confirm that L-His is the preferred ligand, but that 1-methyl-L-His and 3-methyl-L-His can also bind, while the dipeptide carnosine binds weakly and D-histidine and the histidine degradation products, histamine, urocanic acid and imidazole do not bind. L-Arg, homo-L-Arg, and post-translationally modified methylated Arg-analogs also bind with reasonable avidity, with the exception of symmetric dimethylated-L-Arg. In contrast, L-Lys and L-Orn have considerably weaker interactions with HisJ and methylated and acetylated Lys variants show relatively poor binding. It was also observed that the carboxylate group of these amino acids and their variants was very important for proper recognition of the ligand. Taken together our results are a key step towards designing HisJ as a specific protein-based reagentless biosensor.
authors.affiliation: Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Alberta, T2N 1N4, Canada.
authors.forename: Subrata
authors.initials: S
authors.lastname: Paul
authors.affiliation: Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Alberta, T2N 1N4, Canada.
authors.forename: Sambuddha
authors.initials: S
authors.lastname: Banerjee
authors.affiliation: Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Alberta, T2N 1N4, Canada.
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Vogel
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D006639:Histidine / Q000031:analogs & derivatives* / Q000378:metabolism*; D008024:Ligands; D033902:Periplasmic Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D029968:Escherichia coli Proteins; D008024:Ligands; D033902:Periplasmic Binding Proteins; C018963:histidine-binding protein; D006639:Histidine
keywords: HisJ; biosensor; ligand binding; periplasmic protein