Characterization of amyloidogenic intermediate states through a combined use of CD and NMR spectroscopy.
Characterization of amyloidogenic intermediate states is of central importance in understanding the molecular mechanism of amyloid formation. In this study, we utilized CD and NMR spectroscopy to investigate secondary structure of the monomeric amyloidogenic intermediate of a beta-structured SH3 domain, which was induced by trifluoroethanol (TFE). The combined biophysical studies showed that the native state SH3 domain is gradually converted to the amyloidogenic intermediate state at TFE concentrations of 20-26% (v/v) and the aggregation-prone state contains substantial amount of the beta-sheet conformation ( approximately 30%) with disordered (54%) and some helical characters (16%). Under weaker amyloidogenic conditions of higher TFE concentrations (>40%), the beta-sheet structures were gradually changed to helical conformations and the relative content of the helical and beta-sheet conformations was highly correlated with the aggregation propensity of the SH3 domain. This indicates that the beta-sheet characters of the amyloidogenic states may be critical to the effective amyloid formation.
Lim
Kwang Hun
KH
Department of Chemistry, East Carolina University, Greenville, NC 27858, United States. limk@ecu.edu
Le
Yen T H
YT
Collver
Hilary H
HH
Putnam-Evans
Cindy
C
Kenney
John M
JM
D058227:Amyloidogenic Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D019906:Nuclear Magnetic Resonance, Biomolecular; D019869:Phosphatidylinositol 3-Kinases / Q000737:chemistry; D017433:Protein Structure, Secondary; D018909:src Homology Domains
D058227:Amyloidogenic Proteins; D019869:Phosphatidylinositol 3-Kinases