title: Identification of small-molecule inhibitors against SecA by structure-based virtual ligand screening.
abstract: The rapid rise of antibiotic-resistant bacteria is one of the major concerns in modern medicine. Therefore, to treat bacterial infections, there is an urgent need for new antibacterials-preferably directed against alternative bacterial targets. One such potential target is the preprotein translocation motor SecA. SecA is a peripheral membrane ATPase and a key component of the Sec secretion pathway, the major route for bacterial protein export across or into the cytoplasmic membrane. As SecA is essential for bacterial viability, ubiquitous and highly conserved in bacteria, but not present in eukaryotic cells, it represents an attractive antibacterial target. Using an in silico approach, we have defined several potentially druggable and conserved pockets on the surface of SecA. We show that three of these potentially druggable sites are important for SecA function. A starting collection of ~500 000 commercially available small-molecules was virtually screened against a predicted druggable pocket in the preprotein-binding domain of Escherichia coli SecA using a multi-step virtual ligand screening protocol. The 1040 top-scoring molecules were tested in vitro for inhibition of the translocation ATPase activity of E. coli SecA. Five inhibitors of the translocation ATPase, and not of basal or membrane ATPase, were identified with IC50 values <65 μm. The most potent inhibitor showed an IC50 of 24 μm. The antimicrobial activity was determined for the five most potent SecA inhibitors. Two compounds were found to possess weak antibacterial activity (IC50 ~198 μm) against E. coli, whereas some compounds showed moderate antibacterial activity (IC50 ~100 μm) against Staphylococcus aureus.
authors.affiliation: Laboratory of Molecular Bacteriology, Rega Institute for Medical Research, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.
authors.forename: Evelien
authors.initials: E
authors.lastname: De Waelheyns
authors.affiliation: Laboratory of Molecular Bacteriology, Rega Institute for Medical Research, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Segers
authors.affiliation: Laboratory of Molecular Bacteriology, Rega Institute for Medical Research, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.
authors.forename: Marios Frantzeskos
authors.initials: MF
authors.lastname: Sardis
authors.affiliation: Laboratory of Molecular Bacteriology, Rega Institute for Medical Research, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.
authors.forename: Jozef
authors.initials: J
authors.lastname: Anné
authors.affiliation: Cardiovascular Research Institute Maastricht, Department of Biochemistry, Maastricht University, Maastricht, The Netherlands.
authors.forename: Gerry A F
authors.initials: GA
authors.lastname: Nicolaes
authors.affiliation: Laboratory of Molecular Bacteriology, Rega Institute for Medical Research, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.|Institute of Molecular Biology and Biotechnology-FoRTH, Department of Biology-University of Crete, Iraklio, Crete, Greece.
authors.forename: Anastassios
authors.initials: A
authors.lastname: Economou
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors*; D004353:Drug Evaluation, Preclinical; D008024:Ligands; D026901:Membrane Transport Proteins; D000069816:SEC Translocation Channels; D000081416:SecA Proteins
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D008024:Ligands; D026901:Membrane Transport Proteins; D000069816:SEC Translocation Channels; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins