Fig. 3

Involvement of the three variable sub-regions of C2 in the modulation of Env functionality. In each panel, a schematic representation of the chimerical Env is provided on the left and the level of functionality on the right. Color code: Env A white, Env B grey, env G black. a, b Search for restoration of functionality starting from C2 chimeras. a Envelopes generated starting from the A C2G chimera by replacement of R1, R2, and R3 from isolate A. Percentages of functionality were calculated as for Fig. 1. n varies between 3 and 9, depending on the sample considered. b Envelopes generated starting from the B C2G chimera by replacement of R1, R2, and R3 from isolate B. n varies between 3 and 9, depending on the sample considered. c Env generated by inserting in wt B Env the sequence R1 from isolate G. The functionality of the B C2G chimera is given as reference on the left of the dotted line. n varies between 4 and 9, according to the sample considered