Beating the heat--fast scanning melts silk beta sheet crystals.
Sci Rep
; 3: 1130, 2013.
Article
in En
| MEDLINE
| ID: mdl-23350037
ABSTRACT
Beta-pleated-sheet crystals are among the most stable of protein secondary structures, and are responsible for the remarkable physical properties of many fibrous proteins, such as silk, or proteins forming plaques as in Alzheimer's disease. Previous thinking, and the accepted paradigm, was that beta-pleated-sheet crystals in the dry solid state were so stable they would not melt upon input of heat energy alone. Here we overturn that assumption and demonstrate that beta-pleated-sheet crystals melt directly from the solid state to become random coils, helices, and turns. We use fast scanning chip calorimetry at 2,000 K/s and report the first reversible thermal melting of protein beta-pleated-sheet crystals, exemplified by silk fibroin. The similarity between thermal melting behavior of lamellar crystals of synthetic polymers and beta-pleated-sheet crystals is confirmed. Significance for controlling beta-pleated-sheet content during thermal processing of biomaterials, as well as towards disease therapies, is envisioned based on these new findings.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Silk
Limits:
Animals
Language:
En
Journal:
Sci Rep
Year:
2013
Document type:
Article
Affiliation country:
United States