TY - JOUR
T1 - Synthesis and evaluation of fluorescent Pam3Cys peptide conjugates
AU - Gential, Geoffroy P.P.
AU - Ho, Nataschja I.
AU - Chiodo, Fabrizio
AU - Meeuwenoord, Nico
AU - Ossendorp, Ferry
AU - Overkleeft, Herman S.
AU - van der Marel, Gijs A.
AU - Filippov, Dmitri V.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - Chirally pure R- and S-epimers of TLR2 ligand Pam3CysSK4were prepared and separately conjugated to an OVA model epitope, in which lysine was replaced by azidonorleucine. The azide function in the conjugate permitted labelling with different fluorophores by use of strain-promoted 3+2 cycloaddition. The R-epimer of the labelled conjugates induced TLR2-dependent DC maturation, while S-epimer proved to be inactive. Combining the lipophilicity of Pam3CysSK4ligand with fluorophores influenced the solubility of the resulting conjugates in an unpredictable way and only the conjugates labelled with Cy-5 were suitable for confocal fluorescence microscopy experiments. It was shown that both epimers of the Cy-5 labelled lipopeptides were internalized equally well, indicating TLR2-independent cellular uptake. The presented results demonstrate the usefulness of strain-promoted azide-alkyne cycloaddition in the labelling of highly lipophilic lipopeptides without disturbing the in vitro activity of these conjugates with respect to activation of TLR-2.
AB - Chirally pure R- and S-epimers of TLR2 ligand Pam3CysSK4were prepared and separately conjugated to an OVA model epitope, in which lysine was replaced by azidonorleucine. The azide function in the conjugate permitted labelling with different fluorophores by use of strain-promoted 3+2 cycloaddition. The R-epimer of the labelled conjugates induced TLR2-dependent DC maturation, while S-epimer proved to be inactive. Combining the lipophilicity of Pam3CysSK4ligand with fluorophores influenced the solubility of the resulting conjugates in an unpredictable way and only the conjugates labelled with Cy-5 were suitable for confocal fluorescence microscopy experiments. It was shown that both epimers of the Cy-5 labelled lipopeptides were internalized equally well, indicating TLR2-independent cellular uptake. The presented results demonstrate the usefulness of strain-promoted azide-alkyne cycloaddition in the labelling of highly lipophilic lipopeptides without disturbing the in vitro activity of these conjugates with respect to activation of TLR-2.
KW - Fluorescent labeling
KW - Lipopeptides
KW - Strain promoted cycloaddition
KW - Toll-like receptor 2
UR - http://www.scopus.com/inward/record.url?scp=84973484161&partnerID=8YFLogxK
U2 - 10.1016/j.bmcl.2016.05.094
DO - 10.1016/j.bmcl.2016.05.094
M3 - Article
C2 - 27289322
AN - SCOPUS:84973484161
VL - 26
SP - 3641
EP - 3645
JO - Bioorganic and Medicinal Chemistry Letters
JF - Bioorganic and Medicinal Chemistry Letters
SN - 0960-894X
IS - 15
ER -