Title
Heat-induced conformational changes of patatin, the major potato tuber protein
Author
Pots, A.M.
de Jongh, H.H.J.
Gruppen, H.
Hamer, R.J.
Voragen, A.G.J.
Centraal Instituut voor Voedingsonderzoek TNO
Publication year
1998
Abstract
This paper presents a first structural characterization of isolated patatin, the major potato tuber protein, at ambient and elevated temperatures. Isolated patatin at room temperature is a highly structured molecule at both secondary and tertiary levels. It is estimated from far-ultraviolet circular dichroism data that about 33% of the residues adopts an α-helical and 46% a β-stranded structure. Patatin is thermally destabilized at temperatures exceeding 28°C, as was indicated by near-ultraviolet circular dichroism. It was shown that parts of the α-helical contributions unfold in the 45-55°C region, whereas the β-stranded parts unfold more gradually at temperatures of 50-90°C. This was confirmed with Fourier-transform infrared spectroscopy. Differential scanning calorimetry indicated a cooperative transition between 50-60°C, most likely reflecting the unfolding of α-helical parts of the molecule. Furthermore, fluorescence spectroscopy confirmed a global unfolding of the protein between 45-55°C. The observed unfolding of the protein coincides with the inactivation of the patatin enzyme activity and with the precipitation as occurs in the potato fruit juice upon heating. At high temperatures, patatin still contains some helical and stranded structures. Upon cooling the protein partly refolds, it was observed that mainly α-helical structures were formed.
Subject
Nutrition
Conformational change
Patatin
Solanum tuberosum
Enzyme
Vegetable protein
Alpha helix
Circular dichroism
Conformational transition
Differential scanning calorimetry
Enzyme conformation
Enzyme inactivation
Fluorescence spectroscopy
Infrared spectroscopy
Nonhuman
Potato
Priority journal
Protein denaturation
Protein folding
Protein secondary structure
Temperature
Thermostability
Butyrates
Calorimetry, Differential Scanning
Carboxylic Ester Hydrolases
Circular Dichroism
Enzyme Stability
Esterases
Plant Proteins
Protein Conformation
Protein Folding
Protein Structure, Secondary
Protein Structure, Tertiary
Solanum tuberosum
Spectrometry, Fluorescence
Spectroscopy, Fourier Transform Infrared
Temperature
Tryptophan
Solanum tuberosum
Tuberosum
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TNO identifier
234374
ISSN
0014-2956
Source
European Journal of Biochemistry, 252 (1), 66-72
Document type
article