Subunit structure and inhibition specificity of α-type phospholipase A2 inhibitor from Protobothrops flavoviridis
- 作者：Akiko Shimada ; Naoki Ohkura ; Kyozo Hayashi ; Yuji Samejima ; Tamotsu Omori-Satoh ; Seiji Inoue ; Kiyoshi Ikeda
- 关键词：Phospholipase A2 ; Phospholipase A2 inhibitor ; Inhibition specificity ; Snake plasma ; Trimeric structure ; C-type lectin-like domain
- 刊名：Toxicon
- 出版年：2008
- 期刊代码：50_00410101
- 类别：pha
- 出版时间：April 2008
- 卷：51
- 期：5
- 页码：787-796
- 文件大小：290 K
摘要
The 
-type phospholipase A2 inhibitor (PLI) in the plasma of the Habu snake, Protobothrop flavoviridis, was shown to be a trimer of two homologous subunits, PLI-A and PLI-B, each of which contains one C-type lectin-like domain (CTLD). Since one molecule of trimeric PLI binds stoichiometrically to one molecule of P. flavoviridis acidic phospholipase A2 (PLA2), the trimeric structure is critical for its inhibitory activity. Hydrophobic chromatography separated the purified P. flavoviridis PLI into four different trimeric subspecies, A3-PLI, A2B-PLI, AB2-PLI, and B3-PLI, with different combinations of the two subunits. The trimeric PLI could be reconstituted from the purified subunits, and the four different trimeric subspecies were formed through random association of the two subunits. The inhibitory activity of the PLI-A homotrimer (A3-PLI) was more specific than that of the PLI-B homotrimer (B3-PLI). This difference in inhibitory properties between the two homotrimers was probably caused by the amino acid differences at residues 10–37.
-type phospholipase A2 inhibitor (PLI) in the plasma of the Habu snake, Protobothrop flavoviridis, was shown to be a trimer of two homologous subunits, PLI-A and PLI-B, each of which contains one C-type lectin-like domain (CTLD). Since one molecule of trimeric PLI binds stoichiometrically to one molecule of P. flavoviridis acidic phospholipase A2 (PLA2), the trimeric structure is critical for its inhibitory activity. Hydrophobic chromatography separated the purified P. flavoviridis PLI into four different trimeric subspecies, A3-PLI, A2B-PLI, AB2-PLI, and B3-PLI, with different combinations of the two subunits. The trimeric PLI could be reconstituted from the purified subunits, and the four different trimeric subspecies were formed through random association of the two subunits. The inhibitory activity of the PLI-A homotrimer (A3-PLI) was more specific than that of the PLI-B homotrimer (B3-PLI). This difference in inhibitory properties between the two homotrimers was probably caused by the amino acid differences at residues 10–37.