Viral capsid protein

A **viral capsid protein** is a structural component forming the protective shell—called a *capsid*—that surrounds and safeguards a virus's genetic material. The primary functions are to protect the nucleic acid from environmental hazards such as enzymes, pH changes, temperature extremes, and radiation; facilitate delivery and release of the genome into host cells; mediate interactions with host cell receptors during infection; and assist in packaging newly formed genomes during replication cycles[1][3][5]. Capsids can be composed of one or several types of repeating subunits called *capsomeres*, which assemble into various geometric structures—most commonly helical rods or icosahedral spheres—with remarkable stability due to extensive inter-subunit interactions[2]. The major classification criterion for many viruses is their type and arrangement of these structural proteins. Some antiviral strategies aim at disrupting these processes by targeting specific steps in assembly/disassembly unique to each virus family. The term "viral capsid protein" does not refer to a single molecule but rather a class/family found across diverse viruses. Each individual virus encodes its own distinct set(s) of these proteins—for example, VP1–VP4 in poliovirus—or major/minor forms like Vp54 in PBCV‑1[2]. Thus, while "viral capsid protein" is an essential therapeutic target class for infectious disease intervention strategies against many pathogenic viruses, it must always be specified further by particular species/virus context when considering drug development or diagnostics.

Other names

Capsid proteinViral coat proteinMajor capsid protein (MCP)Coat protein (CP)Capsomer (when referring to the structural subunit)

Mechanisms depend on the drug and virus but include: - Inhibition of capsid assembly or disassembly, preventing proper formation or uncoating of the virion. - Stabilization or destabilization of the capsid structure, blocking release or entry of genetic material.