FIG. 1.

Construction of HIV-1 library. (A) Schematic of the HIV-1 library construction carrying a set of random combinations of zero to 11 amino acids. (B) Oligonucleotide sequences used for insertion of 12 nucleotide substitutions in protease. (The residue at position 82 contains two sequential nucleotide substitutions.) LTR, long terminal repeat. The 5′ ends of the oligonucleotides, except for those of PRL1 and PRL10, were chemically phosphorylated. W = A or T, R = A or G, and Y = C or T. The protease-encoding region is underlined.