Midterm #3: Viral Genome Part 2 Flashcards Preview

Medchem 570 > Midterm #3: Viral Genome Part 2 > Flashcards

Flashcards in Midterm #3: Viral Genome Part 2 Deck (11):

Drug Targets in HIV Lifecyle

  • Receptor Binding
  • Membrane Fusion
  • RT (RNA to DNA)
  • DNA integration
  • Polyprotein proteolysis 

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HIV has 3 stages of Attachement

  • Heparan sulfate for initial adhesion
  • CD4 Receptor binding for intial triggering
  • Chemokine coreceptor binding for fusion inititation 
    • CCR5 (predominantly) 
    • CXCR-4

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  • Inhibits HIV entry
    • Binds CCR5 and prevents its interaction with the gp120 subunit of HIV Env (the viruses cell entry machienary)
    • Not effective for CXCR4-tropic HIV

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HIV Entry/Fusion Inhibitor

  • Target the HIV envelope protein (gp120/gp41)
  • Prevent env, specifically gp41 subunit from carrying out fusion of the virus and host membrane 



  • Fuzeon ®
  • Roche ®
  • Entry/Fusion inhibitor
  • Binds to transient prehairpin intermediate coformation of gp41 during fusion

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Nucleoside RT Inhibitors

  • Target drug to dNTP active site, just as with nucleoside inhibitor such as acyclovir and herpesvirus DNA polymerase


Non-Nucleoside RT Inhibitor

  • bind to an allosteric site of RT and decrease RT activity 


HIV Reverse Transcriptase

  • Transcribes RNA genome into DNA so that it can be incorporated into the host genome and passed onto all progeny cells
  • Analgous to DNA polymerase, however, RNA template instead of DNA template
  • Mutations are introduced at the RNA-->DNA step



  • Inhibit HIV DNA viral integration
  • Isentress ®
  • Targets HIV integrase enzyme
    • drops viral loads by 2x vs standard (2NRTI) alone


Protease Inhibitors

  • HIV protease is homodimeric aspartyl protease
  • Cleaves gag and pol polyproteins into functional subunits to produce mature HIV particles
    • gag: into capsid, matric, nucleocapsid
    • pol: into protease, reversetranscriptase, integrase

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Examples of Herpes Virus dsDNA

  • (+)RNA made from dsDNA by host polymerase
  • Virally genomic DNA by viral DNA polymerase
    • Can target specically with antiviral drugs that have specificity for viral polymerase over host polymerase
    • Not the case for pappilomavirus or polyomaviruses