Bovine pancreatic ribonuclease (RNase A) forms two types of dimers (a major and a minor component) upon concentration in mild acid. These two dimers exhibit different biophysical and biochemical properties. Earlier we reported that the minor dimer forms by swapping its N-terminal. alpha -helix with that of an identical molecule. Here we find that the major dimer forms by swapping its C-terminal beta -strand, thus revealing the first example of three-dimensional (3D) domain swapping taking place in different parts of the same protein. This feature permits RNase A to form tightly bonded higher oligomers. The hinge loop of the major dimer, connecting the swapped beta -strand to the protein core, resembles a short segment of the polar zipper proposed by Perutz and suggests a model for aggregate formation by 3D domain swapping with a polar zipper.
Titolo: | A domain-swapped RNase A dimer with implications for amyloid formation |
Autori: | |
Data di pubblicazione: | 2001 |
Rivista: | |
Handle: | http://hdl.handle.net/11562/307167 |
Appare nelle tipologie: | 01.01 Articolo in Rivista |