Virus Structure - Homa Flashcards
Viral genomes are always surrounded by…
A protein capsid
The viral genome enclosed within a capsid is called…
Nucleocapsid
What is a capsomere
A clustering of capsid proteins visualized by EM.
Which structures do neutralizing antibodies target on enveloped and non-enveloped viruses.
For enveloped viruses, neutralizing antibodies target proteins on the envelope surface (usually glycoproteins). For non-enveloped viruses, antibodies target capsid proteins.
Which type of symmetry do most viruses utilize?
Helical and icosahedral
Most symmetrical viruses have ____ capsids.
Icosahedral
Viruses with helical capsids are always…
Enveloped
Metal shadowing and negative staining pros cons
High contrast
Dehydration of sample alters structure
Cryo EM pros and cons
No dehydration needed, structure preserved
Low contrast, higher noise
The highest resolution images of capsid structures are usually solved by
X-ray crystallography
The number of structural units per face of an icosahedron is called…
T-number
The minimum number of subunits per face on an icosahedral virus is
60 (T=1).
If the T-number of a virus with icosahedral symmetry = 3, what is the total number of subunits per face?
Total = 60T
60(3) = 180 subunits
Concerted assembly
Genome is packaged into the capsid as the capsid is assembled
Sequential assembly
Genome is packaged into a preformed capsid
Ex. herpesvirus
