FIG. 1.

Structures of the CA recombinants and mutants used in this study. (A) Construction of CA recombinants NL-SC1, NL-SC2, and NL-SC3. Three restriction enzymes (NsiI, SpeI, and XbaI from left to right in the schema) were used to make these recombinants. Two translationally silent mutations were introduced to generate a NsiI site in MA239 CA and a XbaI site in NL432 CA. The SpeI site is commonly present in authentic NL432 CA and MA239. Structural characteristics are indicated on the upper part. Numbers represent amino acid numbers of NL432 CA. MHR, major homology region in CA (32). (B) Amino acid sequences of deletion and insertion mutants of NL432 CA. The sequences of the mutants were compared to those of MA239 and NL432. The CyPA-binding loop of HIV-1 (14) is underlined. The structures of the CA recombinants and mutants in the figure were confirmed by nucleotide sequencing.