NMR spectroscopy of HIV-1 gp120 outer domain

Background The outer domain (OD) of HIV-1 gp120 has been proposed as a minimal immunogen to elicit broadly neutralizing antibodies. However, OD is heavily glycosylated, contains many flexible regions, and immunization with a number of different OD variants has thus far failed to elicit neutralizing antibodies. An understanding of the conformational space sampled by the OD in its unliganded state, however, may assist in the use of OD as an immunogen.