Publications

2024

• Mesure de la transparence cornéenne par l’analyse d’images oct
  
  • Plamann Karsten
  • Vilbert Maëlle
  • Bocheux Romain
  • Georgeon Cristina
  • Borderie Vincent
  • Pernot Pascal
  • Irsch Kristina
  Photoniques, EDP Sciences, 2024 (127), pp.46-51. La cornée est la première des deux lentilles de l’oeil. La transparence de la cornée saine est due à sa structure très régulière qui peut être perturbée en présence de pathologies. Pour diagnostiquer la transparence cornéenne, nous avons développé des méthodes basées sur l’analyse d’images obtenues par tomographie par cohérence optique (OCT) qui permettent d’obtenir des valeurs physiques comme le libre parcours moyen des photons et le pourcentage de transmission cohérente de la lumière, qui impactent la vision. (10.1051/photon/202412746)
  DOI : 10.1051/photon/202412746
• Structure of a DNA G-quadruplex that Modulates SP1 Binding Sites Architecture in HIV-1 Promoter
  
  • de Rache Aurore
  • Marquevielle Julien
  • Bouaziz Serge
  • Vialet Brune
  • Andreola Marie-Line
  • Mergny Jean-Louis
  • Amrane Samir
  Journal of Molecular Biology, Elsevier, 2024, 436 (2), pp.168359. Nucleic acid sequences containing guanine tracts are able to form non-canonical DNA or RNA structures known as G-quadruplexes (or G4s). These structures, based on the stacking of G-tetrads, are involved in various biological processes such as gene expression regulation. Here, we investigated a G4 forming sequence, HIVpro2, derived from the HIV-1 promoter. This motif is located 60 nucleotides upstream of the proviral Transcription Starting Site (TSS) and overlaps with two SP1 transcription factor binding sites. Using NMR spectroscopy, we determined that HIVpro2 forms a hybrid type G4 structure with a core that is interrupted by a single nucleotide bulge. An additional reverse-Hoogsteen AT base pair is stacked on top of the tetrad. SP1 transcription factor is known to regulate transcription activity of many genes through the recognition of Guanine-rich duplex motifs. Here, the formation of HIVpro2 G4 may modulate SP1 binding sites architecture by competing with the formation of the canonical duplex structure. Such DNA structural switch potentially participates to the regulation of viral transcription and may also interfere with HIV-1 reac- tivation or viral latency. (10.1016/j.jmb.2023.168359)
  DOI : 10.1016/j.jmb.2023.168359
• The control of nitric oxide dynamics and interaction with substituted zinc-phthalocyanines
  
  • Ben Brahim Nassim
  • Touaiti Sarra
  • Sellés Julien
  • Lambry Jean-Christophe
  • Negrerie Michel
  Dalton Transactions, Royal Society of Chemistry, 2024, 53 (2), pp.772-780. Phthalocyanines are artificial macrocycles that can harbour a central metal atom with four symmetric coordinations. Similar to metal-porphyrins, metal-phthalocyanines (M-PCs) may bind small molecules, especially diatomic gases such as NO and O2. Furthermore, various chemical chains can be grafted at the periphery of the M-PC macrocycle, which can change its properties, including the interaction with diatomic gases. In this study, we synthesized Zn-PCs with two different substituents and investigated their effects on the interaction and dynamics of nitric oxide (NO). Time-resolved absorption spectroscopy from picosecond to millisecond revealed that NO dynamics dramatically depends on the nature of the groups grafted to the Zn-PC macrocycle. These experimental results were rationalized by DFT calculations, which demonstrate that electrostatic interactions between NO and the quinoleinoxy substituent modify the potential energy surface and decrease the energy barrier for NO recombination, thus controlling its affinity. (10.1039/d3dt03356b)
  DOI : 10.1039/d3dt03356b