BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Short Talk 7\, Ryan Oliver - Integrative structural biology with c omplementary experimental methods to describe viral capsid protein self-as sembly DTSTART;VALUE=DATE-TIME:20191010T101000Z DTEND;VALUE=DATE-TIME:20191010T103000Z DTSTAMP;VALUE=DATE-TIME:20260525T152710Z UID:indico-contribution-138-765@lindico453.srv.lu.se DESCRIPTION:Speakers: Ryan Oliver (Dept of Biochemistry and Structural Bio logy)\nThe genetic code of viruses\, RNA or DNA\, are typically protected in an icosahedral capsid\, which is primarily\nassembled from over a hundr ed subunits of the same protein in a spontaneous self-assembly process. Si milar\nhighly efficient assembly processes are ubiquitous in biological sy stems\; viral capsids present a unique platform\nto exploit for therapeuti c advances in the targeted cellular delivery of cargo packaged within the capsid.\nOur research aims to provide a more detailed understanding of how this precise viral capsid protein assembly\nprocess occurs from a pool of single building blocks\, and additionally the effect and organization of nucleic\nacid present during assembly. Here\, we present results from smal l-angle neutron scattering experiments using\ncontrast variation to reveal the final assembled structural organization of both the protein and nucle ic\nacid components from recombinant Hepatitis B virus (HBV) capsid protei n and a synthetically prepared RNA\ncontaining the capsid protein binding domain. These data revealed that RNA was localized along the inner capsid\ nsurface. Time-resolved small-angle x-ray scattering (SAXS) experiments we re also used to determine the\nstructure during HBV capsid assembly in the presence and absence of RNA. We employed Bayesian statisticsbased\ncomput ational methods to extract kinetic parameters of assembly and the overall size and shape of the\ndominant structural intermediates from the SAXS dat a. Additional single-particle cryoEM reconstructions are\nprovided to asse ss the effect of RNA on the resulting assembled capsid structure. The comb ination of timeresolved\nscattering data\, Bayesian statistics\, and cryoE M structural analysis\, provides a framework which not\nonly describes the viral self-assembly process\, but can be extended to other hierarchical a ssemblies in biology.\n\nhttps://lindico453.srv.lu.se/event/125/contributi ons/765/ LOCATION:Kulturen Auditorium URL:https://lindico453.srv.lu.se/event/125/contributions/765/ END:VEVENT BEGIN:VEVENT SUMMARY:Short Talk 6\, Mikael B. L. Winkler - STRUCTURAL INSIGHT INTO EUKA RYOTIC STEROL TRANSPORT THROUGH NIEMANN-PICK TYPE C PROTEINS DTSTART;VALUE=DATE-TIME:20191010T091000Z DTEND;VALUE=DATE-TIME:20191010T093000Z DTSTAMP;VALUE=DATE-TIME:20260525T152710Z UID:indico-contribution-138-763@lindico453.srv.lu.se DESCRIPTION:Speakers: Mikael Winkler (Aarhus University)\nNiemann-Pick typ e C (NPC) proteins are essential for sterol homeostasis\, believed to driv e sterol integration into the vacuolar/lysosomal membrane before redistrib ution to other cellular membranes. Using a combination of crystallography\ , cryo-electronmicroscopy\, biochemical and in vivo studies on the Sacchar omyces cerevisiae NPC system\, NCR1/NPC2\, we recently generated a framewo rk for sterol membrane integration (Winkler et al.\, (2019)). Sterols are transferred between hydrophobic pockets of vacuolar NPC2 and membrane-prot ein NCR1. NCR1 has its N terminal domain (NTD) positioned to deliver a ste rol to a tunnel connecting NTD to the luminal membrane leaflet 50 Å away. A sterol is caught inside this tunnel during transport\, and a proton-rel ay network of charged residues in the transmembrane region is linked to th is tunnel supporting a proton-driven transport mechanism. We propose a mod el for sterol integration which clarifies the role of NPC proteins in this essential eukaryotic pathway and which rationalizes mutations in patients with Niemann-Pick disease Type C that I will present at the talk.\n\nWink ler et al\, Structural insight into eukaryotic sterol transport through Ni emann-Pick Type C proteins\, Cell (accepted\, 2019)\n\nhttps://lindico453. srv.lu.se/event/125/contributions/763/ LOCATION:Kulturen Auditorium URL:https://lindico453.srv.lu.se/event/125/contributions/763/ END:VEVENT BEGIN:VEVENT SUMMARY:Keynote 6\, Dr. Andrey Gruzinov: Small-angle X-ray scattering (SAX S) for integrative structural biology DTSTART;VALUE=DATE-TIME:20191010T093000Z DTEND;VALUE=DATE-TIME:20191010T101000Z DTSTAMP;VALUE=DATE-TIME:20260525T152710Z UID:indico-contribution-138-764@lindico453.srv.lu.se DESCRIPTION:Speakers: Andrey Gruzinov (EMBL c/o DESY\, Hamburg\, Germany)\ nSmall-angle X-ray scattering (SAXS) is a powerful method in the studies o f solutions of biological macromolecules and nanostructured systems [1] al lowing one to analyze the structure of native particles and complexes and to rapidly assess structural changes in response to variations in external conditions. Dedicated high brilliance synchrotron beamlines and novel dat a analysis methods [2] significantly enhanced resolution and reliability o f the structural models provided by SAXS. Very important is the ability of SAXS to quantitatively characterize complicated systems and mixtures in n ative environments and to see the biomolecules in action by rapidly observ ing responses to changing physical and chemical conditions (e.g. upon pH o r temperature changes\, ligand binding etc). \nGiven the limited informati on content in the scattering data\, robust data analysis and modelling met hods are of major importance for broad applications of solution SAXS in bi ology. To reduce the ambiguity of interpretation\, SAXS is often combined with other structural methods like crystallography\, NMR and electron micr oscopy\, and also with computational\, biophysical and biochemical techniq ues to build hybrid models. In classical applications\, SAXS generally yie lds low resolution quaternary structure but\, very importantly\, the metho d can also help to analyze equilibrium mixtures and to visualize flexible portions of the structures\, not seen by the high resolution methods. \nIn the present talk\, modern methods for SAXS data analysis will be presente d and illustrated by applications to characterize structures and conformat ional transitions of biological macromolecules in solution. Recent develop ments including\, in particular\, in-line chromatography approaches [3] wi ll be elucidated and perspectives of the synergistic use of SAXS for integ rative modeling utilizing complementary methods will be discussed.\n\nhttp s://lindico453.srv.lu.se/event/125/contributions/764/ LOCATION:Kulturen Auditorium URL:https://lindico453.srv.lu.se/event/125/contributions/764/ END:VEVENT END:VCALENDAR