Effect of shortening Ω-loop D on 3D domain swapping in cytochrome <i>c</i>

Abstract Three-dimensional domain swapping (3D-DS) properties of wild-type human cyt c and its variants, in which one to five residues were deleted from Ω-loop D, were investigated. The cyt c dimer stability generally decreased as more amino acids were deleted from Ω-loop D. However, the del82-85 dimer exhibited a relatively small dissociation rate constant and hydrodynamic size, indicating that protein–protein interactions between the functional globular units play a crucial role in determining the stability of the 3D-DS dimer.