title: Effect of antimicrobial peptides on ATPase activity and proton pumping in plasma membrane vesicles obtained from mycobacteria.
abstract: The potential usefulness of antimicrobial peptides (AMPs) as antimycobacterial compounds has not been extensively explored. Although a myriad of studies on AMPs from different sources have been done, some of its mechanisms of action are still unknown. Maganins are of particular interest since they do not lyse non-dividing mammalian cells. In this work, AMPs with well-recognized activity against bacteria were synthesized, characterized, purified and their antimycobacterial activity and influence on ATPase activity in mycobacterial plasma membrane vesicles were assessed. Using bioinformatics tools, a magainin-I analog peptide (MIAP) with improved antimicrobial activity was designed. The influence of MIAP on proton (H(+)) pumping mediated by F(1)F(0)-ATPase in plasma membrane vesicles obtained from Mycobacterium tuberculosis was evaluated. We observed that the antimycobacterial activity of AMPs was low and variable. However, the activity of the designed peptide MIAP against M. tuberculosis was 2-fold higher in comparison to magainin-I. The basal ATPase activity of mycobacterial plasma membrane vesicles decreased approximately 24-30% in the presence of AMPs. On the other hand, the MIAP peptide completely abolished the F(1)F(0)-ATPase activity involved in H(+) pumping across M. tuberculosis plasma membranes vesicles at levels similar to the specific inhibitor N,N' dicyclohexylcarbodiimide. These finding suggest that AMPs can inhibit the H(+) pumping F(1)F(0)-ATPase of mycobacterial plasma membrane that potentially interferes the internal pH and viability of mycobacteria.
authors.affiliation: Chemistry Department, Faculty of Sciences, Universidad Nacional de Colombia, Bogotá, Colombia.
authors.forename: Paola
authors.initials: P
authors.lastname: Santos
authors.forename: Aldemar
authors.initials: A
authors.lastname: Gordillo
authors.forename: Luis
authors.initials: L
authors.lastname: Osses
authors.forename: Luz-Mary
authors.initials: LM
authors.lastname: Salazar
authors.forename: Carlos-Yesid
authors.initials: CY
authors.lastname: Soto
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000302:isolation & purification / Q000494:pharmacology*; D025243:Bacterial Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D052978:Disk Diffusion Antimicrobial Tests; D008969:Molecular Sequence Data; D020102:Mycobacterium smegmatis / Q000187:drug effects / Q000201:enzymology*; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000201:enzymology*; D017433:Protein Structure, Secondary; D013347:Subcellular Fractions / Q000187:drug effects / Q000201:enzymology
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D025243:Bacterial Proton-Translocating ATPases