title: Rational design of novel peptidic DnaK ligands.
abstract: The hsp70 chaperone DnaK from E. coli plays a major role in cellular stress response and is involved in assisted protein folding in vivo. By screening a combinatorial peptide library, we identified several DnaK-specific peptide ligands with nanomolar affinities, which are able to inhibit the secondary amide peptide bond cis/trans isomerase (APIase) activity of DnaK, as well as DnaK/DnaJ/GrpE-assisted refolding of firefly luciferase. Our designed DnaK inhibitors have the capability to penetrate E. coli cells and feature a high protease resistance. Once inside the cell, they physically target DnaK. NMR-based (1)H/(15)N-HSQC experiments furthermore confirmed that the designed peptidic ligands all bind in an identical manner to the conventional peptide-binding site of DnaK. The subsequent blocking of DnaK function apparently results in the observed antibacterial effects on E. coli cells, with minimum inhibitory concentrations in the range of 100 microM.
authors.affiliation: Max Planck Research Unit for Enzymology of Protein Folding, Weinbergweg 22, 06120 Halle-Saale, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Liebscher
authors.forename: Katja
authors.initials: K
authors.lastname: Haupt
authors.forename: Chao
authors.initials: C
authors.lastname: Yu
authors.forename: Günther
authors.initials: G
authors.lastname: Jahreis
authors.forename: Christian
authors.initials: C
authors.lastname: Lücke
authors.forename: Cordelia
authors.initials: C
authors.lastname: Schiene-Fischer
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000494:pharmacology*; D001667:Binding, Competitive; D002463:Cell Membrane Permeability; D004926:Escherichia coli / Q000378:metabolism*; D004927:Escherichia coli Infections / Q000188:drug therapy*; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D020128:Inhibitory Concentration 50; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D019151:Peptide Library; D017510:Protein Folding
chemical_list: D023181:Antimicrobial Cationic Peptides; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D008024:Ligands; D019151:Peptide Library; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli