ABSTRACT
The coding capacity of viral genomes varies from below 5 to over 100 genes. This in turn is reflected in the different complexities of virus particles and their respective replication cycles. Viral proteins are either structural (part of the virion architecture) or nonstructural and of these some are found in the virion (usually enzymes) while others are present only within infected cells. Nonstructural proteins can have a range of functions, often mimicking those of cellular enzymes, and many are multifunctional.
