The easiest and often most useful way to work with experimentally determined or computationally predicted structures of biomolecules is by viewing their three-dimensional (3D) shapes using a molecular visualization tool. Mol* was collaboratively developed by RCSB Protein Data Bank (RCSB PDB, RCSB.org) and Protein Data Bank in Europe (PDBe, PDBe.org) as an open-source, web-based, 3D visualization software suite for examination and analyses of biostructures. It is capable of displaying atomic coordinates and related experimental data of biomolecular structures together with a variety of annotations, facilitating basic and applied research, training, education, and information dissemination. Across RCSB.org, the RCSB PDB research-focused web portal, Mol* has been implemented to support single-mouse-click atomic-level visualization of biomolecules (e.g., proteins, nucleic acids, carbohydrates) with bound cofactors, small-molecule ligands, ions, water molecules, or other macromolecules. RCSB.org Mol* can seamlessly display 3D structures from various sources, allowing structure interrogation, superimposition, and comparison. Using influenza A H5N1 virus as a topical case study of an important pathogen, we exemplify how Mol* has been embedded within various RCSB.org tools-allowing users to view polymer sequence and structure-based annotations integrated from trusted bioinformatics data resources, assess patterns and trends in groups of structures, and view structures of any size and compositional complexity. In addition to being linked to every experimentally determined biostructure and Computed Structure Model made available at RCSB.org, Standalone Mol* is freely available for visualizing any atomic-level or multi-scale biostructure at rcsb.org/3d-view.

• Klíčová slova
• 3D biostructure, Protein Data Bank, global health, influenza A H5N1 virus, molecular visualization, open‐source, pandemic preparedness, viral pathogen, virus life cycle, web‐based,
• MeSH
• databáze proteinů MeSH
• konformace proteinů MeSH
• molekulární modely MeSH
• proteom * chemie   MeSH
• software * MeSH
• virové proteiny chemie   MeSH
• virus chřipky A, podtyp H5N1 * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• proteom * MeSH
• virové proteiny MeSH

Neuraminidase is the main target for current influenza drugs. Reduced susceptibility to oseltamivir, the most widely prescribed neuraminidase inhibitor, has been repeatedly reported. The resistance substitutions I223V and S247N, alone or in combination with the major oseltamivir-resistance mutation H275Y, have been observed in 2009 pandemic H1N1 viruses. We overexpressed and purified the ectodomain of wild-type neuraminidase from the A/California/07/2009 (H1N1) influenza virus, as well as variants containing H275Y, I223V, and S247N single mutations and H275Y/I223V and H275Y/S247N double mutations. We performed enzymological and thermodynamic analyses and structurally examined the resistance mechanism. Our results reveal that the I223V or S247N substitution alone confers only a moderate reduction in oseltamivir affinity. In contrast, the major oseltamivir resistance mutation H275Y causes a significant decrease in the enzyme’s ability to bind this drug. Combination of H275Y with an I223V or S247N mutation results in extreme impairment of oseltamivir’s inhibition potency. Our structural analyses revealed that the H275Y substitution has a major effect on the oseltamivir binding pose within the active site while the influence of other studied mutations is much less prominent. Our crystal structures also helped explain the augmenting effect on resistance of combining H275Y with both substitutions.

• Klíčová slova
• crystal structure, influenza neuraminidase, isothermal titration calorimetry, oseltamivir, resistance,
• MeSH
• antivirové látky farmakologie   MeSH
• chřipka lidská virologie   MeSH
• inhibitory enzymů farmakologie   MeSH
• kalorimetrie MeSH
• kinetika MeSH
• krystalizace MeSH
• lidé MeSH
• missense mutace MeSH
• neuraminidasa chemie   genetika   MeSH
• oseltamivir farmakologie   MeSH
• replikace viru MeSH
• substituce aminokyselin MeSH
• termodynamika MeSH
• virová léková rezistence genetika   MeSH
• virové proteiny chemie   genetika   MeSH
• virus chřipky A, podtyp H1N1 účinky léků   enzymologie   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antivirové látky MeSH
• inhibitory enzymů MeSH
• neuraminidasa MeSH
• oseltamivir MeSH
• virové proteiny MeSH