Western blot analysis of envelope proteins incorporated into virions of ConB and alanine328 mutants. Viral lysates prepared from ConB, 328AV, 328AG, 328AK, and 328AE viruses were reacted with a HIV-1-positive human serum. Molecular mass markers, 97 kDa, 69 kDa, 46 kDa, 30 kDa, and 14 kDa are shown in lane MW.