DOPC and DOPC/DHA lipid bilayers.

<p>(a) Height AFM images of DOPC (2.5×2.5 µm² 1024×1024px²) and DOPC/DHA (b) (2.5×2.5 512×512px²) lipid bilayers performed in tapping mode and in PBS. The bilayers cover 92% (DOPC) and 96% (DOPC/DHA) of the mica surface. On DOPC lipid particles collected at the border or within defects are due to incomplete bilayer formation or to defective rinsing.</p

Aβ(25-35) aggregation on DOPC/DHA lipid bilayer.

<p>(a-c) 5×2.2 µm² (1024×431px²) topographic AFM images of Aβ(25-35) aggregation on DOPC/DHA lipid bilayers. (d) Graph showing the increasing surface area covered by LA (blue line) and the lipid bilayer evolution over time (red line). LA structures were grown within the first 30 min of peptide deposition while the lipid surface area decreased slowly from 96% to 91%. Data were qualitatively fitted by rational and sigmoidal functions for the DOPC/DHA bilayer (Θ_DOPC/DHA) and the LA domains (Θ_P), respectively. Fitting curves act as guide-to-the-eye. (e) Height distribution histograms measured at t = 0 min (black), 30 min (red), 1 h (green), 1 h45 min (blue), 2 h (cyan) and 2 h20 min (magenta).</p

Aggregation of Aβ(25-35) on mica.

<p>Topographic AFM images of Aβ(25-35) aggregates grown on mica. Images were acquired in tapping mode and in PBS. (a) After 6 hours, Aβ(25-35) forms a smooth homogeneous layer without any well-formed aggregates (3×3 µm², 2459×2459px²). (b) On a smaller scale the peptide tends to organize into a texture with some discernible protrusions (white ellipse) (500×500 nm², 1228×1228px²).</p

Aβ(25-35) high resolution analysis.

<p>Topographic AFM images (a, c) and corresponding phase images (b, d) performed in PBS on the same area (360×360 nm², 1024×1024 px²) of Aβ(25-35) LA domains on the DOPC bilayer. Images were acquired with an average tip-sample force of 170pN by scanning from left to right (a, b) and from right to left (c, d). Topographies clearly show both globular aggregates (circled) and annular structures (squared). The complex LA aggregate (arrow) in the bottom right-hand corner and the globular aggregate in the top right-hand corner (insets) are perturbed by the tip movement. (e, f) Height (black) and phase (red) line profiles of globular (e) and annular structures (f) measured along the white dashed line in Fig. 6a and 6c. (g,h) Height images of a highly dense globular structure region (286×286 nm², 574×574px²) acquired with two different tip-sample forces. At 220 pN (g), the globular structures are not perturbed, while at 234 pN (h) they are mechanically removed leaving the underlying annular structures. (i, l) AFM height images (770×770 nm², 633×633 px²) of LA on two different regions of the DOPC/DHA bilayer. After 1 h45 min of peptide deposition (i) the LA presents a linear organization highlighted by grey fibres. After 2 h20 min (l) the LA forms a structured layer where linear organization is less visible though still distinguishable. In some locations, it is organized into annular structures (red circles) similar in dimension but more sporadic and of different nature compared to the ones observed on DOPC.</p

Structural Evidence of <i>N</i>6‑Isopentenyladenosine As a New Ligand of Farnesyl Pyrophosphate Synthase

<i>N</i>6-isopentenyladenosine (i6A), a modified nucleoside belonging to the cytokinin family, has shown in humans many biological actions, including antitumoral effects through the modulation of the farnesyl pyrophosphate synthase (FPPS) activity. To investigate the relationship between i6A and FPPS, we undertook an inverse virtual screening computational target searching, testing i6A on a large panel of 3D protein structures involved in cancer processes. Experimentally, we performed an NMR investigation of i6A in the presence of FPPS protein. Both inverse virtual screening and saturation transfer difference (STD) NMR outcomes provided evidence of the structural interaction between i6A and FPPS, pointing to i6A as a valuable lead compound in the search of new ligands endowed with antitumoral potential and targeting FPPS protein

Designed Glucopeptides Mimetics of Myelin Protein Epitopes As Synthetic Probes for the Detection of Autoantibodies, Biomarkers of Multiple Sclerosis

We previously reported that CSF114­(Glc) detects diagnostic autoantibodies in multiple sclerosis sera. We report herein a bioinformatic analysis of myelin proteins and CSF114­(Glc), which led to the identification of five sequences. These glucopeptides were synthesized and tested in enzymatic assays, showing a common minimal epitope. Starting from that, we designed an optimized sequence, SP077, showing a higher homology with both CSF114­(Glc) and the five sequences selected using the bioinformatic approach. SP077 was synthesized and tested on 50 multiple sclerosis patients’ sera, and was able to detect higher antibody titers as compared to CSF114­(Glc). Finally, the conformational properties of SP077 were studied by NMR spectroscopy and structure calculations. Thus, the immunological activity of SP077 in the recognition of specific autoantibodies in multiple sclerosis patients’ sera may be ascribed to both the optimized design of its epitopic region and the superior surface interacting properties of its C-terminal region