The morphology of virus particles. Classification of viruses

Norrby, Erling

This chapter focuses on the studies on morphology of virus particles and their classification. The composition of a conventional virus can be described as follows. Centrally, the particle contains nucleic acid of varying quantity. This nucleic acid is either RNA or DNA but never both kinds simultaneously. Only certain non-enveloped virions can be crystallized. The availability of viral crystals has facilitated three-dimensional analyses by aid of X-ray diffraction. Through earlier studies, it has been possible to shed light upon the interaction between virus nucleic acid and capsid protein. A single-stranded nucleic acid can direct the synthesis of a protein that has a size corresponding to about 1/7 of its molecular weight. Nature generally utilizes symmetrical building principles in the construction of more comprehensive three-dimensional structures. The name of Coronavirus has been given to designate the pattern of the club-like peplomers that radiate from the envelope.