Structural elements of Trimeresurus flavoviridis serum inhibitors for recognition of its venom phospholipase A2 isozymes.
Five inhibitors (PLI-I-V) against Trimeresurus flavoviridis (Tf, habu snake, Crotalinae) venom phospholipase A2 (PLA2) isozymes have been isolated from its serum. PLI-I, which is composed of two repeated three-finger motifs, and PLI-IV and PLI-V, which contain a sequence similar to the carbohydrate recognition domain (CRD) of C-type lectins, were expressed in the forms fused with glutathione S-transferase (GST). The resulting GST-PLIs showed ability to bind to three Tf venom PLA2 isozymes. The binding study with the truncated forms indicated that one of two three-finger motifs of PLI-I was able to bind to PLA2 isozymes. The N-terminal 37-amino acid fragment and the CRD-like domain of PLI-IV and PLI-V were bound to PLA2 isozymes. On the other hand, their C-terminal 12-amino acid segment also associated with PLA2 isozymes. When either of two units of a hydrophobic tripeptide in this sequence was replaced by trialanine, the binding was completely abolished, indicating that the C-terminal hydrophobic cores of PLI-IV and PLI-V were critically responsible for the binding to venom PLA2 isozymes.
Nobuhisa
I
I
Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka, Japan.
Chiwata
T
T
Fukumaki
Y
Y
Hattori
S
S
Shimohigashi
Y
Y
Ohno
M
M
D000818:Animals; D001798:Blood Proteins / Q000378:metabolism / Q000494:pharmacology*; D003435:Crotalid Venoms / Q000201:enzymology*; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D010446:Peptide Fragments / Q000378:metabolism / Q000494:pharmacology; D010741:Phospholipases A / Q000037:antagonists & inhibitors*; D054467:Phospholipases A2; D011485:Protein Binding; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D017841:Trimeresurus
D001798:Blood Proteins; D003435:Crotalid Venoms; D007527:Isoenzymes; D010446:Peptide Fragments; D010741:Phospholipases A; D054467:Phospholipases A2