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Viruses are the intracellular obligate microorganisms having either DNA or RNA, but not the both. Viruses are the molecular nanomachine that comes in variety of shapes, size and require host machinery to complete its life cycle.
During the last couple of years after the concept given by Caspar and Klug regarding virus construction, high resolution structural studies using X-ray crystallography and cryo-EM techniques have build up the knowledge and understanding of structural organization in viruses.
Viruses are metastable macromolecular assemblies composed of the viral genome enclosed within a proteinaceous coat i.e. capsid. Irrespective of their shape and size, the ultimate motive of all the virus structure is designed to contain and protect the viral genome and deliver it to a specific host cell for subsequent replication of the virus. The viral genome, in addition to encoding the proteins that constitute the capsid, also encodes other proteins referred to as nonstructural proteins, so called because they are not part of the final capsid organization. These nonstructural proteins are essential for viral replication inside the host cell. In some viruses, particularly of bacterial origin, viral genome encodes a protein called scaffolding protein that may not be part of the mature capsid but may be a critical factor in facilitating the capsid assembly (Prasad et al. 2012).
The size of the virus is proportional to the size of the genome. But capsid proteins contribute more than viral genome towards total mass of the virion. Capsid formation involves both a single gene and multi gene products depending upon viruses. Studies on capsid assembly helps in designing various antiviral strategies.
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I am currently pursuing Ph.D in Animal Biotechnology from Indian Veterinary Research Institute