Figure 7

Cartoon of the complex of Vpr and CypA. The cartoon shows the 30 KDa complex of CypA with full-length Vpr where selected residues of the cooperative N- and C-terminal binding domains of Vpr and the two binding sites of CypA suggested by Demange et al. are high-lighted [30]. Residues Pro-35 and Arg-80 of Vpr are highlighted in yellow. Leu-122 of the Pro-dependent S1' subsite and Arg-148 of the Pro-independent S2'-S3' subsite of CypA are highlighted in green [30]. The structures of CypA and Vpr used in the model of the complex are derived from the pdb files of the X-ray structure of CypA at 1.63 Å resolution [51] and the NMR structure of Vpr obtained in aqueous 30% acetonitrile solution at low pH [45]. At physiological pH Vpr is mainly structured in a membranous environment and exhibits a more flexible structure under hydrophilic solution which is similar to the experimental conditions used in the SPR experiments (aqueous buffer pH 7.4) [8, 53].