Viral protein

Overview

Diagram of a hexon protein structure

A viral protein is a protein encoded by a virus's genome. Viral proteins are essential for the virus's ability to infect and replicate within a host cell. These proteins can be structural, forming part of the virus's physical structure, or non-structural, playing roles in the virus's replication and interaction with the host's immune system.

Types of Viral Proteins

Viral proteins can be broadly categorized into structural and non-structural proteins.

Structural Proteins

Structural proteins are components of the virus particle, or virion. They include:

• Capsid proteins: These proteins form the protective shell around the viral nucleic acid. The capsid is crucial for protecting the viral genome and aiding in its delivery into host cells.

• Envelope proteins: Found in enveloped viruses, these proteins are embedded in the viral envelope and are involved in the attachment and entry of the virus into host cells.

• Matrix proteins: These proteins link the viral envelope with the capsid, providing structural integrity to the virion.

Non-Structural Proteins

Non-structural proteins are not part of the virion structure but are essential for viral replication and pathogenesis. They include:

• Enzymes: Such as RNA-dependent RNA polymerase and reverse transcriptase, which are crucial for the replication of the viral genome.

• Regulatory proteins: These proteins modulate the host's cellular machinery to favor viral replication and suppress the host's immune response.

• Accessory proteins: These proteins can have various functions, including modulating the host's immune response or enhancing viral replication.

Function of Viral Proteins

Viral proteins have diverse functions that are critical for the virus's life cycle. They are involved in:

• Attachment and entry: Viral proteins mediate the attachment of the virus to host cell receptors and facilitate entry into the cell.

• Replication: Enzymatic proteins are involved in the replication of the viral genome.

• Assembly and release: Structural proteins are involved in the assembly of new virions and their release from the host cell.

• Immune evasion: Some viral proteins help the virus evade the host's immune system, allowing for persistent infection.

Importance in Medicine

Viral proteins are targets for antiviral drugs and vaccines. Understanding the structure and function of these proteins can lead to the development of therapeutic interventions. For example, the hexon protein, depicted in the image, is a major capsid protein of adenoviruses and is a target for vaccine development.

Related Pages

• Virus
• Capsid
• Viral replication
• Antiviral drug
• Vaccine