1. Name the protein!

a. Host receptor involved in SARS-CoV-2 entry:

ACE2 (Angiotensin-Converting Enzyme 2)

b. Viral adhesion protein:

Spike (S) protein

c. Other important proteins involved:

• TMPRSS2 (host protease that primes Spike protein)
• RNA-dependent RNA polymerase (RdRp)
• Nucleocapsid (N) protein
• Membrane (M) protein
• Envelope (E) protein

2. Refer to your diagram. What steps would you target an antiviral drug against? Why? (List as many as you can!)

Targetable steps:

• Attachment/entry – block Spike-ACE2 binding (e.g. antibodies or entry inhibitors)
• Fusion and uncoating – prevent release of viral RNA
• RNA replication – inhibit RNA-dependent RNA polymerase (e.g. Remdesivir)
• Protease processing – block viral proteases needed to cleave polyproteins
• Assembly/release – disrupt packaging or budding (though harder to target specifically)

These steps are specific to the virus and avoid harming host cell processes.

3. Should we target translation for antiviral drugs as well?

No. Viruses use the host’s ribosomes to translate their proteins. Targeting translation would harm human cells too.

4. Do your antiviral targets change depending on the class of virus you are treating?

Yes. Different virus classes (e.g., DNA vs. RNA viruses, retroviruses, etc.) replicate in different ways and use different enzymes. For example:

• Retroviruses need reverse transcriptase
• RNA viruses use RNA-dependent RNA polymerase
• DNA viruses may rely more on host DNA replication machinery

So, drug targets must match the virus type and its life cycle.