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Capsid

a protein coat that covers the nucleoprotein core or nucleic acid of a virion. Commonly shows icosahedral symmetry and may itself be enclosed in an envelope (as in the Togaviridae). The capsid is built up of subunits (some integer multiple of 60, the number required to give strict icosahedral symmetry) that self assemble in a pattern typical of a particular virus. The subunits are often packed, in smaller capsids, into 5 or 6 membered rings (pentamers or hexamers) that constitute the morphological unit (capsomere). The packing of subunits is not perfectly symmetrical in most cases and some units may have strained interactions and are said to have quasi equivalence of bonding to adjacent units. A variety of leaf bug.The outer covering of protein surrounding the nucleic acid of a virus.The protein coat that surrounds the dna or mrna of a virus.