Identification of lipid binding and lipoprotein lipase activation domains of human apoAV.
ApoAV, a newly discovered apolipoprotein, plays a key role in human triglyceride homeostasis; however, the structure-function correlation of apoAV is not clearly understood. To explore the relationship, wild type and six deletion mutants, that is (AV (Delta(1-51)), AV (Delta(51-128)), AV (Delta(132-188)), AV (Delta(192-238)), AV (Delta(246-299)), AV (Delta(301-343))), of human apoAV expressed in Escherichia coli were studied. All the deleted regions together encompass almost the entire 343 amino acid sequence of wild type apoAV. Circular dichroism spectroscopy showed that the alpha helical content of lipid-free wild type apoAV was 46%. In comparison with wild type apoAV, AV (Delta(192-238)) and AV (Delta(301-343)) displayed significantly decreased lipid binding activities, confirming the importance of these two regions in lipid binding function of apoAV. While, the LPL activation function of apoAV remarkably impaired after deletion of residues 192-238. These findings suggested that the domain (192-238) is absolutely necessary for apoAV in lipid binding and lipoprotein lipase activation.
Sun
Guotao
G
Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China.
Bi
Nan
N
Li
Guoping
G
Zhu
Xuewei
X
Zeng
Wuwei
W
Wu
Gang
G
Xue
Hong
H
Chen
Baosheng
B
D000818:Animals; D000072040:Apolipoprotein A-V; D001053:Apolipoproteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001054:Apolipoproteins A; D002417:Cattle; D002942:Circular Dichroism; D004789:Enzyme Activation; D015870:Gene Expression; D006801:Humans; D007700:Kinetics; D050356:Lipid Metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D011487:Protein Conformation
C437704:APOA5 protein, human; D000072040:Apolipoprotein A-V; D001053:Apolipoproteins; D001054:Apolipoproteins A; D008071:Lipoprotein Lipase