Fig. 4.

Speculative dissociation mechanism of the proposed RNase A minor trimer. A model for the RNase A minor trimer was constructed, with its threefold axis replacing the twofold axis in the major dimer. During dissociation, one subunit (blue) departs the trimer molecule and refolds into the monomer, whereas the other two subunits (red and green) form the major dimer. Because the proposed model of the minor trimer is symmetric, the dissociation of the green or red subunit will result in the same products. The figure was created using Raster 3D (Merritt and Bacon 1997).