Download MendeleyStructure of amyloid beta fragments in aqueous environments
Takano, K., Endo, S., Mukaiyama, A., Chon, H., Matsumura, H., Koga, Y., Kanaya, S.(2006) FEBS J 273: 150-158
- PubMed: 16367755
- DOI: https://doi.org/10.1111/j.1742-4658.2005.05051.x
- Primary Citation of Related Structures:
1X1P - PubMed Abstract:
Conformational studies on amyloid beta peptide (Abeta) in aqueous solution are complicated by its tendency to aggregate. In this study, we determined the atomic-level structure of Abeta(28-42) in an aqueous environment. We fused fragments of Abeta, residues 10-24 (Abeta(10-24)) or 28-42 (Abeta(28-42)), to three positions in the C-terminal region of ribonuclease HII from a hyperthermophile, Thermococcus kodakaraensis (Tk-RNase HII). We then examined the structural properties in an aqueous environment. The host protein, Tk-RNase HII, is highly stable and the C-terminal region has relatively little interaction with other parts. CD spectroscopy and thermal denaturation experiments demonstrated that the guest amyloidogenic sequences did not affect the overall structure of the Tk-RNase HII. Crystal structure analysis of Tk-RNase HII(1-197)-Abeta(28-42) revealed that Abeta(28-42) forms a beta conformation, whereas the original structure in Tk-RNase HII(1-213) was alpha helix, suggesting beta-structure formation of Abeta(28-42) within full-length Abeta in aqueous solution. Abeta(28-42) enhanced aggregation of the host protein more strongly than Abeta(10-24). These results and other reports suggest that after proteolytic cleavage, the C-terminal region of Abeta adopts a beta conformation in an aqueous environment and induces aggregation, and that the central region of Abeta plays a critical role in fibril formation. This study also indicates that this fusion technique is useful for obtaining structural information with atomic resolution for amyloidogenic peptides in aqueous environments.
Organizational Affiliation:
Department of Material and Life Science, Osaka University, Suita, Japan. ktakano@mls.eng.osaka-u.ac.jp
