title: The insect antimicrobial peptide, L-pyrrhocoricin, binds to and stimulates the ATPase activity of both wild-type and lidless DnaK.
abstract: Recent reports have indicated that insect antimicrobial peptides kill bacteria by inhibiting the molecular chaperone DnaK. It was proposed that the antimicrobial peptide, all-L-pyrrhocoricin (L-PYR), binds to two sites on DnaK, the conventional substrate-binding site and the multi-helical C-terminal lid, and that inhibition of DnaK comes about from the lid mode of binding. In this report, we show using two different assays that L-PYR binds to and stimulates the ATPase activity of both wild-type and a lidless variant of DnaK. Our study shows that L-PYR interacts with DnaK much like the all-L NR (NRLLLTG) peptide, which is known to bind in the conventional substrate-binding site of DnaK. L-PYR antimicrobial activity is thus a consequence of the competitive inhibition of bacterial DnaK.
authors.affiliation: Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA.
authors.forename: Liudmila S
authors.initials: LS
authors.lastname: Chesnokova
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Slepenkov
authors.forename: Stephan N
authors.initials: SN
authors.lastname: Witt
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000494:pharmacology; D001665:Binding Sites; D004305:Dose-Response Relationship, Drug; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D019476:Insect Proteins; D007313:Insecta; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013050:Spectrometry, Fluorescence; D013696:Temperature; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D018840:HSP70 Heat-Shock Proteins; D019476:Insect Proteins; D010455:Peptides; C087710:pyrrhocoricin protein, Pyrrhocoris apterus; D000251:Adenosine Triphosphatases