Figure 6

Characterization of CypA binding to N-terminal peptides of s Vpr. Synthetic Vpr^1-20(A), Vpr^21-40 (B), Vpr^25-40 (C), Vpr^1-40(D) and synthetic mutants carrying Pro to Asn exchanges at amino acid positions 5, 10 and 14(s Vpr^1-40P5,10,14N) (E) and at position 35 (s Vpr^1-40 P35N) (F) were tested for binding to immobilized recombinant CypA using a SPR biosensor system. A, B and C were injected at concentrations ranging from 0-400 μM over CM5 chip immobilized with 918 RU CypA, while D, E and F were injected at concentrations ranging from 0-200 μM. The curves A, B, C, D and E were best fit to a two state reaction model (Fig. 7). k_a1, k_a2, k_d1, k_d2 and K_D were calculated for respective sensograms (Table 1).