Conservation of inner domain modules in the surface envelope glycoproteins of an ancient rabbit lentivirus and extant lentiviruses and betaretroviruses.

The consensus sequence of endogenous lentiviral elements in the genome of European rabbits (RELIK) was used to extend a model of conserved lentiviral and betaretroviral surface envelope glycoprotein (SU) inner domain structures. Here it is shown that nearly all the inner domain elements of human and simian immunodeficiency virus gp120 mediating conformational changes upon CD4 binding were conserved in the SU of RELIK. Many of these inner domain elements and a carboxy-terminal region outside the gp120 core are also conserved in the SU of other lentiviruses and betaretroviruses, suggesting conserved mechanisms of SU conformational changes induced by receptor binding.