During domain swapping, proteins mutually interconvert structural elements to
form a di-/oligomer. Engineering this process by design is important for
creating a higher order protein assembly with minimal modification. Herein, a
simple design strategy is shown for domain-swapping formation by loop deletion
and insertion of a polyproline rod. Crystal structures revealed the formation of
the domain-swapped dimers and polyproline portion formed a polyproline II
(PPII) structure. Small-angle X-ray scattering demonstrated that an extended
orientation of domain-swapped dimer was retained in solution. It is found that a
multiple of three of inserting proline residue is favored for domain swapping
because of the helical nature of PPII. The rigid nature of the polyproline rod
enables precise control of the interdomain distance and orientation.
Links
