Proceedings book download - 5Z.com

Proceedings of the 31 st European Peptide SymposiumMichal Lebl, Morten Meldal, Knud J. Jensen, Thomas Hoeg-Jensen (Editors)European Peptide Society, 2010Synthesis of a PEG Conjugated HIV Gp41 MPER Fragment:A New Gp41 Helix Bundle MimicManuela Grimaldi 1 , Antonia Mastrogiacomo 1 , Daniela Eletto 1 ,Mario Scrima 1 , Simone Giannecchini 2 , Fabio Rizzolo 3,4 ,Paolo Rovero 3,4 , and Anna M. D'Ursi 11 Department of Pharmaceutical Science, University of Salerno, Fisciano, I- 84084, Italy;2 Department of Public Health, Firenze, I-50134, Italy; 3 Department of PharmaceuticalScience, University of Firenze, Sesto Fiorentino, I-50019, Italy; 4 Laboratory of Peptide &Protein Chemistry & Biology, Univeristy of Firenze, I-50019, Sesto Fiorentino, ItalyIntroductionHuman Immunodeficiency Virus (HIV), responsible for acquired immunodeficiencysyndrome (AIDS), perform cell entry via a molecular mechanism involving viral Envglycoproteins with the final fusion mediated by the surface glycoproteins Gp41. The globalarchitecture of Gp41 consists of a transmembrane (TM) region separating the cytoplasmicdomain from the ectodomain enclosing the membrane-proximal external regions (MPER)directly involved in the virus cell fusion. In particular the fusion mechanism occurs throughconformational changes of three Gp41 with the interaction of three Gp41 N-terminalhelices forming a highly stable six helix bundle and the MPER effecting the events thatoccur after merging of the viral and cell membrane. Peptides deriving from MPER in theectodomain of TM glycoprotein are able to prevent HIV cell membrane fusion [1], and oneof these, formerly peptide T-20, is clinically used as anti HIV fusion inhibitors [2]. It wasrecently shown that polyethylene glycol (PEG) conjugated dimeric and trimeric fusioninhibitors, selected from a combinatorial peptide database, to mimic the Gp41 trimerichelix bundle, were characterized by a significant increased in antiviral potency [3]. Werecently synthesized and tested for antiviral activity, EPK249 a Trp rich peptidecorresponding to residues 666-681 of Gp41 MPER. EPK249 displayed weak in vitroantiviral activity.Here we present the synthesis of PEG conjugated dimers and trimers of EPK249designed in the attempt to achieve, according to the previous reported strategy, animprovement in the antiviral, fusion inhibitory activity.Results and DiscussionAccording to the approach experimented by Welch [3], we first used the followingsynthetic strategy (Scheme 1):Scheme 1. Synthesis strategy of Welch.The synthetic procedure was repeated several times by slightly changing the experimentalconditions. The different experiments showed that the major obstacle to the success of thereaction was the hydrophobicity of EPK249 sequence. Therefore we designed a syntheticscheme that did not start by the central peptide (EPKK249), but starting by EPK249-PEG(see Scheme 3). This synthetic strategy allowed the obtaining of dimer (Scheme 2) andtrimer (Scheme 4) EPK249 with a high purity.344