Domain structure of the human immunodeficiency virus reverse transcriptase

The spatial arrangement of subunits p51 and p66 of the HIV‐1 reverse transcriptase and the position of the RNase H containing domain, p15, have been determined by means of neutron small‐angle scattering. The reverse transcriptase (p66/p51) is a flat molecule, which can be approximated by an ellipsoid with the half axes of 5.2 nm, 4.8 nm and 1.4 nm. The two subunits p51 and p66 having a centre‐to‐centre distance of 3.3 +/− 0.3 nm are attached at their flat sides, slightly shifted sideways. The p15 domain is located at the long axis of the ellipsoidal reverse transcriptase having a distance of 5.0 +/− 0.5 nm to the centre of the p51d domain, which is part of the p66 subunit, and a distance of 5.3 +/− 1.2 nm to the centre of the neighbouring p51s subunit.