p17

p17 is a designation used in molecular biology to refer to a protein with an approximate molecular mass of 17 kilodaltons. The label is widely used when naming small viral and cellular proteins and is not indicative of a single, universal function; the specific identity and role of a p17 protein depend on the organism and gene from which it is derived.

In HIV-1, p17 denotes the matrix protein encoded by the gag gene. The mature p17 protein is about 132 amino acids in length and is N-terminally myristoylated at glycine-2. This lipid modification promotes membrane association, an essential step in virion assembly. The matrix forms a layer beneath the viral envelope and participates in genome packaging and virus budding, coordinating interactions with the capsid protein p24 and the envelope glycoprotein gp41 after proteolytic processing of the Gag polyprotein. p17 is produced during maturation and is immunogenic, occasionally targeted by host immune responses.

Outside HIV-1, p17 has been used to label other 17-kDa proteins found in different species, including various viruses and bacteria. These proteins are not necessarily homologous to HIV-1 p17 and may have distinct functions. Because the same designation is used for different molecules, precise identification requires reference to the organism, gene name, and experimental context.

See also: protein naming conventions; Gag p17; matrix proteins.