title: Quinolinol and peptide inhibitors of zinc protease in botulinum neurotoxin A: effects of zinc ion and peptides on inhibition.
abstract: Quinolinol derivatives were found to be effective inhibitors of botulinum neurotoxin serotype A (BoNT/A). Studies of the inhibition and binding of 7-(phenyl(8-quinolinylamino)methyl)-8-quinolinol (QAQ) to the light chain domain (BoNT/A LC) showed that QAQ is a non-competitive inhibitor for the zinc protease activity. Binding and molecular modeling studies reveal that QAQ binds to a hydrophobic pocket near the active site. Its inhibitor effect does not involve the removal of zinc ion from the light chain. A 24-mer SNAP-25 peptide containing E183 to G206 with Q197C mutation (Peptide C) binds to BoNT/A LC with an unusually slow second order binding rate constant of 76.7M(-1)s(-1). QAQ binds to Zn(2+)-free BoNT/A LC with a K(D) of 0.67microM and to Peptide C-BoNT/A LC complex with a K(D) of 2.33microM. The insights of the interactions of quinolinols and peptides with the zinc protease of BoNT/A should aid in the development of inhibitors of metalloproteases.
authors.affiliation: Department of Chemistry, Georgetown University, Washington, DC 20057, USA.
authors.forename: Huiguo
authors.initials: H
authors.lastname: Lai
authors.forename: Minghao
authors.initials: M
authors.lastname: Feng
authors.forename: Virginia
authors.initials: V
authors.lastname: Roxas-Duncan
authors.forename: Sivanesan
authors.initials: S
authors.lastname: Dakshanamurthy
authors.forename: Leonard A
authors.initials: LA
authors.lastname: Smith
authors.forename: David C H
authors.initials: DC
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D000634:Aminoquinolines / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D019274:Botulinum Toxins, Type A / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D020134:Catalytic Domain; D002614:Chelating Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006912:Hydroxyquinolines / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D007700:Kinetics; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D017434:Protein Structure, Tertiary; D013050:Spectrometry, Fluorescence; D013696:Temperature; D015032:Zinc / Q000378:metabolism*
chemical_list: C545211:7-(phenyl(8-quinolinylamino)methyl)-8-quinolinol; D000634:Aminoquinolines; D002614:Chelating Agents; D006912:Hydroxyquinolines; D010455:Peptides; D011480:Protease Inhibitors; D008666:Metalloendopeptidases; D019274:Botulinum Toxins, Type A; D015032:Zinc