Association of heat-induced conformational change with activity loss of Rubisco.
Circular dichroism (CD), fluorescence, and differential scanning calorimetry (DSC) were used to investigate the thermal conformational change associated with the activity loss of spinach Rubisco. CD and intrinsic fluorescence demonstrated a three stage thermal unfolding of Rubisco. At 25-45 degrees C, the secondary structure did not change but the tertiary and/or quaternary structure changed obviously with increased temperature. In 45-60 degrees C, the secondary structure showed much change with increased temperature and the tertiary and/or quaternary structure changed much faster. Over 60 degrees C, whole conformation changed abruptly with increased temperature and finally unfolded completely. DSC, CD and activity assays after annealing showed that the conformational change and the activity loss of Rubisco were completely reversible if the heating temperature was below 45 degrees C, partly reversible between 45 and 60 degrees C, and irreversible beyond 60 degrees C.
Li
Guofu
G
State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University, Beijing, 100084, People's Republic of China.
Mao
Haibin
H
Ruan
Xiang
X
Xu
Qiang
Q
Gong
Yandao
Y
Zhang
Xiufang
X
Zhao
Nanming
N
D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D006358:Hot Temperature; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D012273:Ribulose-Bisphosphate Carboxylase / Q000737:chemistry* / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D018724:Spinacia oleracea / Q000201:enzymology*; D013329:Structure-Activity Relationship
D012273:Ribulose-Bisphosphate Carboxylase