HIV-1 is composed of two copies of single-stranded RNA enclosed by a conical capsid comprising the viral protein p24, typical of lentiviruses. As a component of the HIV-virus particle there are approximately 2000 molecules per virus particle, or at a molecule weight of 24 kDa, about 10^4 virus particles per picogram of p24. HIV gag (group-specific antigen): codes for the Gag polyprotein, which is processed during maturation to MA (matrix protein, p17), CA (capsid protein, p24), SP1 (spacer peptide 1, p2), NC (nucleocapsid protein, p7), SP2 (spacer peptide 2, p1) and p6. Alternative Names: gp41 glycoprotein antigen, HIV-1 gp41 antigen, HIV 1 gp41, HIV1 gp41 antigen, HIV-1 gp41 protein, HIV-1 gp41, Glycoprotein 41 antigen, gp41 antigen, SU antigen, HIV 1 gp41 antigen, gp41 antigen, HIV 1 gp41 protein, HIV1 gp41, Surface protein antigen, Envelope surface glycoprotein gp41 antigen, Human Immunodeficiency Virus 1 antigen