Binding studies of antimicrobial lipopeptide Bacillomycin D homologues to model membranes with varying sterol content

AGUSTIN LUNA BULBARELA; SABINA MATÉ; SATHISHKUMAR MUNUSAMY; VANESA HERLAX; CARLOS MUÑOZ-GARAY; ROMINA VAZQUEZ; LEOBARDO SERRANO CARREON

Puebla

Congreso; XX Congreso de Bioenergética y Biomembranas; 2017

Sociedad Mexicana de Bioquímica

This study was designed to examine the interactions between Bacillomycin D homologues with model membrane of different sterol content. Bacillomycin D homologues are cyclic lipopeptides containing seven α-amino acids and a β-amino fatty acid linked by amide bond to the constituent amino acid residue Among the several Bacillomycin D homologues, the ones containing C14 (BC14) and C16 (BC14) β-amino fatty acids are believed to have more antifungi activity. In this context we studied calcein release from liposomes composed by PC:Cho and PC:ergosterol in presence of both lipopeptides. We also explore the capacity of both lipopeptides to form monolayers in water-air interface and the ability of them to insert into monolayer composed by PC: Cho and PC:ergosterol.. On the other hand, the binding efficiency of Bacillomycin analogs was studied by measuring the intrinsic fluorescence of the lipopeptides bound to liposomes of different composition. Further binding information was obtained by quenching experiments with acrylamide. Results obtained from calcein release from liposomes treated with both lipopetides, indicate that lipopeptides are more active in liposomes composed by PC: ergosterol than in those composed by PC and PC:Cho, being BC16 the most active This is in concordance with monolayer experiments where BC16 insert more into monolayers composed by PC:ergosterol than PC:cho and PC.