Emerging Viruses
Sue Delos CWA Jan 23, 30, and Feb 6 2018 Part I Introduc on to Virology
What is a virus? Viral Lifecycle Common Needs Unique solu ons Transmission Routes Classifica on Methods of Visualizing Virion Components Capsid Structures Viral Envelopes Func ons of Structural Proteins Func ons of Nonstructural Proteins Part II Virus-Host Interac ons, Vaccines and Ihibitors Part III Emerging Viruses
The Immune System Zoonoses and Why They Occur Innate Influenza, A Respiratory Virus Adap ve Ebola, A Blood-Borne Virus Viral Countermeasures Zika, A Mosquito Transmi ed Virus Vaccines Vaccines Improve Life Expectancy Dependence upon Herd Immunity Passive Vaccines Ac ve Vaccines Inac vated Virus Subunit Vaccines Subunit Vaccines An virals Requirements for success Poten al Targets The Path of Drug Discovery The HIV experience The HCV experience
Emerging Viruses
Part I Introduc on to Virology What is a Virus?
A virus is an organism with two phases. What would you do if you were a parasite that could only reproduce inside a cell?
Cell A Virus is an Organism with Two Phases Intracellular Extracellular
Disassembly Stable par cle Reproduc on New, stable par cle assembly and release Common Needs 2 phases of viral lifecycle: extracellular and intracellular
• Find permissive cell • Synthesize viral mRNA • Bind cell (transcrip on) • Penetrate membrane • Synthesize viral proteins • Uncoat (transla on) • • Reprogram Cell for own Replicate genome replica on • Assemble and mature • Establish replica on virion center • Release stable virion (lysis or budding)
Structural Protein Func ons Nonstructural Protein Func ons Unique Solu ons
ENTRY: • Uncoa ng • Mul ple receptors • Replica on site • Mul ple modes of entry • Assembly • Surface proteins • Egress • Site of membrane • (Cell-to-cell) penetra on transmission Sites of Viral Entry into the Host
V. Raconelli, MID 31 In humans
Viruses cause a wide range of misery
Image credit: "Preven on and treatment of viral infec ons: Figure 1, by OpenStax College, Biology, CC BY 4.0. Modifica on of original work by Mikael Häggström.
Viruses are Nature’s Nanopar cles
(too small to be observed by tradi onal microscope)
1 μM = 1000 nM The Tools of Viral Structural Biology
• X-ray Crystallography (must have crystals) • But most viruses and their proteins are flexible and do not crystallize
• Electron microscopy (can see par cles)
• CryoEM and Tomography (structures of flexible virions and proteins)
• NMR (structures of regions within protein) The Structural Proteins Capsid Func ons
• Encases and protects gene