Biophysical characterization of purified o-gp140SF162ΔV2 using TDA system. (A) Relative responses obtained for light scattering (LS), refractive index detector (RI), and viscometer (DP) analyses for o-gp140SF162ΔV2. The majority of the purified protein is homogeneous. (B) Summary of biophysical properties, including molecular weight, intrinsic viscosity and hydrodynamic radius, of o-gp140SF162ΔV2 compared to gp120SF162ΔV2.