Subunit structure and inhibition specificity of α-type phospholipase A2 inhibitor from Protobothrops flavoviridis

The alpha-type phospholipase A2 inhibitor (PLIalpha) in the plasma of the Habu snake, Protobothrop flavoviridis, was shown to be a trimer of two homologous subunits, PLIalpha-A and PLIalpha-B, each of which contains one C-type lectin-like domain (CTLD). Since one molecule of trimeric PLIalpha binds...

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Bibliographic Details
Published in:Toxicon (Oxford) 2008-04, Vol.51 (5), p.787-796
Main Authors: SHIMADA, Akiko, OHKURA, Naoki, HAYASHI, Kyozo, SAMEJIMA, Yuji, OMORI-SATOH, Tamotsu, INOUE, Seiji, IKEDA, Kiyoshi
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animal poisons toxicology. Antivenoms
Animals
Biological and medical sciences
Blood Proteins - chemistry
Blood Proteins - pharmacology
Medical sciences
Molecular Sequence Data
Phospholipases A2 - metabolism
Protein Binding
Protein Subunits
Time Factors
Toxicology
Viperidae - blood
Viperidae - metabolism
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Summary:The alpha-type phospholipase A2 inhibitor (PLIalpha) in the plasma of the Habu snake, Protobothrop flavoviridis, was shown to be a trimer of two homologous subunits, PLIalpha-A and PLIalpha-B, each of which contains one C-type lectin-like domain (CTLD). Since one molecule of trimeric PLIalpha 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 PLIalpha into four different trimeric subspecies, A3-PLIalpha, A2B-PLIalpha, AB2-PLIalpha, and B3-PLIalpha, with different combinations of the two subunits. The trimeric PLIalpha 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 PLIalpha-A homotrimer (A3-PLIalpha) was more specific than that of the PLIalpha-B homotrimer (B3-PLIalpha). This difference in inhibitory properties between the two homotrimers was probably caused by the amino acid differences at residues 10-37.
ISSN:0041-0101
1879-3150
DOI:10.1016/j.toxicon.2007.12.014