Citation

Tsai IH, Chang HC, Chen JM, Cheng AC, Khoo KH. FEBS J. 2012; 279(15): 2672-2682.

Affiliation

Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.

Copyright

(Copyright © 2012, John Wiley and Sons)

DOI

10.1111/j.1742-4658.2012.08648.x

PMID

22630045

Abstract

Most of the phospholipases A(2) (PLA(2) s) variants isolated so far from snake venoms are non-glycosylated enzymes. We herein purified an active glycosylated PLA(2) and an inactive non-glycosylated Lys49-like PLA(2) from two geographic venom samples of Tropidolaemus. The PLA(2) variants from the two samples have rather different N-terminal sequences, implying that the samples were probably derived from two species (T. subannulatus and T. wagleri). The active PLA(2) s from Sulawesi and Sumatra venoms were designated as Tsu-E6 and Twa-E6, respectively, due to the presence of their conserved Glu6 residue. Tsu-E6 inhibited ADP-induced aggregation of mouse and human platelets. Twa-E6, however, stimulated the aggregation of mouse platelets but inhibited the aggregation of human platelets. Both of the PLA(2) s were found to be glycosylated at Asn14. Using MALDI-TOF analysis, the released glycans were shown to be complex type oligosaccharides without sialylation. This is the first glycan structure of the snake venom PLA(2) solved. Furthermore, the enzymatic removal of glycans from both the PLA(2) s did not significantly alter their effects on lipid hydrolysis and platelet aggregation. The thermostability of glycosylated Twa-E6 was also found to be as good as those of other homologous PLA(2) s. The presence of these oligosaccharides on the PLA(2) s warrants further analyses which may provide useful insights into the functional regulation of these biomolecules.

Language: en