PEDS Advance Access originally published online on July 14, 2009
Protein Engineering Design and Selection 2009 22(8):531-536; doi:10.1093/protein/gzp037
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
This article appears in the following Protein Engineering issue: Amyloids Special Issue [View the issue table of contents]
Short protein segments can drive a non-fibrillizing protein into the amyloid state
1Departments of Biological Chemistry 2Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics, Howard Hughes Medical Institute, Molecular Biology Institute, UCLA, Box 951570, Los Angeles, CA 90095-1570, USA
3 To whom correspondence should be addressed. E-mail: david{at}mbi.ucla.edu
Protein fibrils termed amyloid-like are associated with numerous degenerative diseases as well as some normal cellular functions. Specific short segments of amyloid-forming proteins have been shown to form fibrils themselves. However, it has not been shown in general that these segments are capable of driving a protein from its native structure into the amyloid state. We applied the 3D profile method to identify fibril-forming segments within the amyloid-forming human proteins tau, alpha-synuclein, PrP prion and amyloid-beta. Ten segments, six to eight residues in length, were chosen and inserted into the C-terminal hinge loop of the highly constrained enzyme RNase A, and tested for fibril growth and Congo red birefringence. We find that all 10 unique inserts cause RNase A to form amyloid-like fibrils which display characteristic yellow to apple-green Congo red birefringence when observed with cross polarizers. These six to eight residue inserts can fibrillize RNase A and are sufficient for amyloid fibril spine formation.
Keywords: amyloid/domain swapping/functional networks/prion structure/protein interactions
Received June 11, 2009; revised June 11, 2009; accepted June 12, 2009.