Transient non-native secondary structures during the refolding of alpha-lactalbumin detected by infrared spectroscopy.
Stopped-flow Fourier-transform infrared spectroscopy (SF-FTIR) was used to identify native as well as non-native secondary structures during the refolding of the calcium-binding protein alpha-lactalbumin. Infrared absorbance spectra were recorded in real time after a pH jump induced refolding of the protein. In the presence of calcium, the refolding is fast with concerted appearance of secondary structures; in its absence, folding is much slower and intricate, with transient formation and disappearance of non-native beta-sheet. The possibility of detecting native as well as non-native structures at the same time is especially valuable in providing insight into the complexity of the refolding process of a protein.
Troullier
A
A
Laboratoire de Biophysique Moléculaire et Cellulaire, URA CNRS 520, Département de Biologie Moléculaire et Structurale, CEA-Grenoble, 17 av. des Martyrs, 38054 GRENOBLE Cedex 09, France.
Reinstädler
D
D
Dupont
Y
Y
Naumann
D
D
Forge
V
V
D000818:Animals; D001059:Apoproteins / Q000737:chemistry / Q000378:metabolism; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D002417:Cattle; D003080:Cold Temperature; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007768:Lactalbumin / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D011489:Protein Denaturation; D017510:Protein Folding; D020673:Protein Renaturation / Q000187:drug effects; D017433:Protein Structure, Secondary / Q000187:drug effects; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
D001059:Apoproteins; D007768:Lactalbumin; D002118:Calcium