FIG 7.

The hydrodynamic radius, R_h, of rhTRIM5α B30.2 and CypA as a function of the concentration of HIV-1 capsid surrogates. R_h, as determined by 2fFCS (see Materials and Methods), is plotted against the concentration of capsid dimer (a), trimer (b), and hexamer (c). Insets show concentrations of up to 0.2 mM capsid monomer equivalents to highlight the difference between B30.2 and CypA binding. The data are fitted with equation 2 (solid lines). For CypA, the two processes contributing to an increase of R_h (capsid binding and viscosity increase) occur over well-separated capsid concentration ranges, allowing the reliable determination of R_h of the CypA-capsid complex and the capsid concentration-dependent increase in viscosity (see Materials and Methods). (d) R_h values determined for rhTRIM5α B30.2, CypA, and the rhTRIM5α/CypA-capsid complexes. Error bars indicate the standard deviation of three independent measurements. The R_h values of CypA and rhTRIM5α B30.2 are identical within error, justifying the assumptions described in Materials and Methods. The hydrodynamic radii of the rhTRIM5α B30.2-capsid surrogate complexes are assumed to be identical to those of the respective CypA-capsid surrogate complexes.