RNA control of HIV-1 particle size polydispersity.

HIV-1, an enveloped RNA virus, produces viral particles that are known to be much more heterogeneous in size than is typical of non-enveloped viruses. We present here a novel strategy to study HIV-1 Viral Like Particles (VLP) assembly by measuring the size distribution of these purified VLPs and subsequent viral cores thanks to Atomic Force Microscopy imaging and statistical analysis. This strategy allowed us to identify whether the presence of viral RNA acts as a modulator for VLPs and cores size heterogeneity in a large population of particles.

AFM investigation of Pseudomonas aeruginosa lectin LecA (PA-IL) filaments induced by multivalent glycoclusters.

Atomic force microscopy reveals that Pseudomonas aeruginosa LecA (PA-IL) and a tetra-galactosylated 1,3-alternate calix[4]arene-based glycocluster self-assemble according to an aggregative chelate binding mode to create monodimensional filaments. Lectin oligomers are identified along the filaments and defects in chelate binding generate branches and bifurcations. A molecular model with alternate 90° orientation of LecA tetramers is proposed to describe the organisation of lectins and glycoclusters in the filaments.