Fig. 4: Competitive inhibition of FCN2 binding to PMOXA- and PEOXA-coated NPs by monosaccharides and amides.

a Localization of the three S2 sites for acetylated compounds, in the trimeric -COOH terminal binding domain of FCN2 (left) and superimposition of pig (green) and human (blue) S2 sites (right). b Two binding modes of N-acetyl-D-glucosamine (GlcNAc) to the S2 binding site of human FCN2, schematically highlighting the substrate coordination by hydrogen bonds and the insertion of hydrophobic aliphatic groups into the two hydrophobic pockets present in the site. c Effect of monosaccharide inhibitors on the binding of FCN2 to PMOXA- and PEOXA-coated NPs. NPs were incubated with PS alone or in the presence of 100 mM GlcNAc (a natural substrate of FCN2), d-mannose (Man), a natural substrate of mannose-binding lectin, and d-galactose (Gal), as negative control. NPs were recovered, washed and FCN2 was identified based on SDS-PAGE mobility (green arrow, representative gel). The histogram represents the inhibition of FCN2 corona abundancy (densitometry of SDS-PAGE) in the presence of monosaccharides (mean ± SD; n = 7 independent experiments). Significant p values (<0.05) are derived from Brown-Forsythe and Welch’s ANOVA and Dunnett’s T3 tests. Source data are provided as Source Data file. d Dose response SDS-PAGE analysis of the amount of pig FCN2 bound to PMOXA-coated NPs after incubation in PS alone or in the presence of increasing doses of GlcNAc, Man, and Gal, as indicated. The IC50% value of GlcNac is shown. Source data are provided as Source Data file. e Effect of amide inhibitors on the binding of FCN2 to PMOXA- and PEOXA-coated NPs. FCN2 (green arrow in a representative gel) was quantified (histogram of band densitometry) in the corona of NPs incubated in PS as in c in the presence of different amides (100 mM): N, N-dimethylpropionamide (DMNPr), N, N-dimethylacetamide (DMNAc), N, N-dimethylformamide (DMNF), N-formamide (MNF) and formamide (NF). The gel is representative and the data of the histogram are mean ± SD (n = 5 for PMOXA-ctrl, n = –4 for other samples). Significant p values (<0.05) are derived from Brown-Forsythe and Welch’s ANOVA and Dunnett’s T3 tests. The structures of amides are shown, revealing overlap with PEOXA monomer (DMNPr) or PMOXA monomer (DMNAc). f Dose response SDS-PAGE analysis of the amount of pig FCN2 bound to PMOXA- and PEOXA-coated NPs after incubation in PS alone or in the presence of increasing doses of dimethylacetamide (DMNAc) and N,N-dimethylpropionamide (DMNPr). The IC50% values are shown. Source data are provided as Source Data file.