Structure and Anti-Stokes Luminescence of Yb-containing Glass Co-doped with Eu, Ho and Er

The aim of our work was synthesis of transparent silicious media high-doped with Yb–Er, Yb–Ho and Yb–Eu and determination of the media structure and spectral-luminescent properties in the anti-Stokes region at excitation through the Yb3+ ions

Structure and Anti-Stokes Luminescence of Yb-containing Glass Co-doped with Eu, Ho and Er

The aim of our work was synthesis of transparent silicious media high-doped with Yb–Er, Yb–Ho and Yb–Eu and determination of the media structure and spectral-luminescent properties in the anti-Stokes region at excitation through the Yb3+ ions

Optical Materials Activated with CeO2:Ln3+ Nanoparticles

Silica glasses and siliceous powders activated with CeO2:Ln3+ (Ln ¹ Ce) nanoparticles were synthesized by the sol-gel method and their structural and spectral-luminescent properties were investigated. It is shown that the main features of the Ln3+ ions are a high relative intensity of magnetic dipole transitions and sufficiently effective sensitization of their luminescence with labile photoreduced (Ce4+)- ions by means of superexchange mechanism or/and by transfer of electron

Optical Materials Activated with CeO2:Ln3+ Nanoparticles

Silica glasses and siliceous powders activated with CeO2:Ln3+ (Ln ¹ Ce) nanoparticles were synthesized by the sol-gel method and their structural and spectral-luminescent properties were investigated. It is shown that the main features of the Ln3+ ions are a high relative intensity of magnetic dipole transitions and sufficiently effective sensitization of their luminescence with labile photoreduced (Ce4+)- ions by means of superexchange mechanism or/and by transfer of electron

Molecular Basis of Spectral Diversity in Near-Infrared Phytochrome-Based Fluorescent Proteins

SummaryNear-infrared fluorescent proteins (NIR FPs) engineered from bacterial phytochromes (BphPs) are the probes of choice for deep-tissue imaging. Detection of several processes requires spectrally distinct NIR FPs. We developed an NIR FP, BphP1-FP, which has the most blue-shifted spectra and the highest fluorescence quantum yield among BphP-derived FPs. We found that these properties result from the binding of the biliverdin chromophore to a cysteine residue in the GAF domain, unlike natural BphPs and other BphP-based FPs. To elucidate the molecular basis of the spectral shift, we applied biochemical, structural and mass spectrometry analyses and revealed the formation of unique chromophore species. Mutagenesis of NIR FPs of different origins indicated that the mechanism of the spectral shift is general and can be used to design multicolor NIR FPs from other BphPs. We applied pairs of spectrally distinct point cysteine mutants to multicolor cell labeling and demonstrated that they perform well in model deep-tissue imaging

Inhibiting HIV-1 Entry Discovery of D-Peptide Inhibitors that Target the gp41 Coiled-Coil Pocket

AbstractThe HIV-1 gp41 protein promotes viral entry by mediating the fusion of viral and cellular membranes. A prominent pocket on the surface of a central trimeric coiled coil within gp41 was previously identified as a potential target for drugs that inhibit HIV-1 entry. We designed a peptide, IQN17, which properly presents this pocket. Utilizing IQN17 and mirror-image phage display, we identified cyclic, D-peptide inhibitors of HIV-1 infection that share a sequence motif. A 1.5 Å cocrystal structure of IQN17 in complex with a D-peptide, and NMR studies, show that conserved residues of these inhibitors make intimate contact with the gp41 pocket. Our studies validate the pocket per se as a target for drug development. IQN17 and these D-peptide inhibitors are likely to be useful for development and identification of a new class of orally bioavailable anti-HIV drugs

Structures of FOX-4 cephamycinase in complex with transition-state analog inhibitors

Boronic acid transition-state analog inhibitors (BATSIs) are partners with β-lactam antibiotics for the treatment of complex bacterial infections. Herein, microbiological, biochemical, and structural findings on four BATSIs with the FOX-4 cephamycinase, a class C β-lactamase that rapidly hydrolyzes cefoxitin, are revealed. FOX-4 is an extended-spectrum class C cephalosporinase that demonstrates conformational flexibility when complexed with certain ligands. Like other β-lactamases of this class, studies on FOX-4 reveal important insights into structure–activity relationships. We show that SM23, a BATSI, shows both remarkable flexibility and affinity, binding similarly to other β-lactamases, yet retaining an IC50 value < 0.1 μM. Our analyses open up new opportunities for the design of novel transition-state analogs of class C enzymes