Inhibition of citrate synthase thermal aggregation in vitro by recombinant small heat shock proteins.
Small heat shock proteins (sHSPs) function as molecular chaperones that protect cells against environmental stresses. In the present study, the genes of hsp17.6 and hsp17.7, cytosolic class I sHSPs, were cloned from a tropical plant, Ageratina adenophorum. Their C-terminal domains were highly conserved with those of sHSPs from other plants, indicating the importance of the C-terminal domains for the structure and activity of sHSPs. The recombinant HSP17.6 and HSP17.7 were applied to determine their chaperone function. In vitro, HSP17.6 and HSP17.7 actively participated in the refolding of the model substrate citrate synthase (CS) and effectively prevented the thermal aggregation of CS at 45 degrees C and the irreversible inactivation of CS at 38 degrees C at stoichiometric levels. The prior presence of HSP17.7 was assumed to suppress the thermal aggregation of the model substrate CS. Therefore, this report confirms the chaperone activity of HSP17.6 and HSP17.7 and their potential as a protectant for active proteins.
Gong
Weina
W
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Yue
Ming
M
Xie
Bingyan
B
Wan
Fanghao
F
Guo
Jianying
J
D036603:Ageratina / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D002950:Citrate (si)-Synthase / Q000737:chemistry* / Q000378:metabolism; D017124:Conserved Sequence; D004926:Escherichia coli / Q000378:metabolism; D050888:Heat-Shock Proteins, Small / Q000737:chemistry / Q000502:physiology*; D018869:Heat-Shock Response; D006358:Hot Temperature; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000502:physiology; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D013552:Swine
D050888:Heat-Shock Proteins, Small; D010940:Plant Proteins; D011994:Recombinant Proteins; D002950:Citrate (si)-Synthase