TY  - JOUR
AU  - Duy, C.
AU  - Fitter, J.
TI  - How aggregation and conformational scrambling of unfolded states govern fluorescence emission spectra
JO  - Biophysical journal
VL  - 90
SN  - 0006-3495
CY  - New York, NY
PB  - Rockefeller Univ. Press
M1  - PreJuSER-51328
SP  - 3704 - 3711
PY  - 2006
N1  - Record converted from VDB: 12.11.2012
AB  - In a case study on five homologous alpha-amylases we analyzed the properties of unfolded states as obtained from treatments with GndHCl and with elevated temperatures. In particular the wavelength of the tryptophan fluorescence emission peak (lambda(max)) is a valuable parameter to characterize properties of the unfolded state. In all cases with a typical red shift of the emission spectrum occurring during structural unfolding we observed a larger magnitude of this shift for GndHCl-induced unfolding as compared to thermal unfolding. Although a quantitative relation between aggregation and reduction of the unfolding induced red shifts cannot be given, our data indicate that protein aggregation contributes significantly to smaller magnitudes of red shifts as observed during thermal unfolding. In addition, other properties of the unfolded states, most probable structural compactness or simply differences in the conformational scrambling, also affect the magnitude of red shifts. For the irreversible unfolding alpha-amylases studied here, transition temperatures and magnitudes of red shifts are strongly depending on heating rates. Lower protein concentrations and smaller heating rates lead to larger red shifts upon thermal unfolding, indicating that under these conditions the protein aggregation is less pronounced.
KW  - Dimerization
KW  - Multiprotein Complexes: analysis
KW  - Multiprotein Complexes: chemistry
KW  - Protein Conformation
KW  - Protein Denaturation
KW  - Protein Folding
KW  - Spectrometry, Fluorescence: methods
KW  - Structure-Activity Relationship
KW  - Temperature
KW  - alpha-Amylases: analysis
KW  - alpha-Amylases: chemistry
KW  - Multiprotein Complexes (NLM Chemicals)
KW  - alpha-Amylases (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:16500981
C2  - pmc:PMC1440751
UR  - <Go to ISI:>//WOS:000236901400033
DO  - DOI:10.1529/biophysj.105.078980
UR  - https://juser.fz-juelich.de/record/51328
ER  -