Structural requirements for the edema-inducing and hemolytic activities of mastoparan B isolated from the hornet (Vespa basalis) venom.

Abstract

Mastoparan B (MP-B) is a cationic tetradecapeptide isolated from the black-bellied hornet (Vespa basalis) venom. It has a primary structure (LKLKSIVSWAKKVL-CONH2) distinct from other vespine mastoparans. The peptide caused a dose-dependent swelling in rat hind paw and showed a potent hemolytic activity in guinea pig red blood cells. Studies on the structure activity relationship of the peptide showed that replacing lysine at position 2 (Lys2) by asparagine (Asn) in the MP-B sequence caused about 40% decrease in its edema-inducing activity at 50 micrograms/paw and 90% decrease in hemolytic activity at 30 microM of the peptide, while the same substitution at Lys4 did not cause a significant change in either activity. Replacing either Lys11 or Lys12 by leucine (Leu) caused little or no decrease in the edema-inducing and hemolytic activities. Decreases in both activities were observed when both Lys11 and Lys12 were replaced by Leu. On the other hand, replacing tryptophan at position 9 (Trp9) by tyrosine or phenylalanine in MP-B sequence almost abolished its hemolytic activity, while the edema-inducing activity was only partially inhibited. Circular dichroism spectra of the peptides measured in 20% trifluoro-ethanol revealed that substitution of Lys and Trp did not cause a significant change in the conformation of MP-B. it appears that Lys2 is crucial for both hemolytic and edema-inducing activities of MP-B, while Trp9 is of special importance to the hemolytic activity of MP-B. Lys11 and Lys12 in MP-B probably play a lesser role in both activities.

• Authors: C L Ho, Y L Lin, W C Chen, L L Hwang, H M Yu, K T Wang
• Journal: Toxicon : official journal of the International Society on Toxinology (Toxicon) Vol. 34 Issue 9 Pg. 1027-35 (Sep 1996) ISSN: 0041-0101 [Print] England
• PMID: 8896194 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Intercellular Signaling Peptides and Proteins
• Peptides
• Tryptamines
• Wasp Venoms
• mastoparan B
• tryptamine
• Lysine

Topics

• Amino Acid Sequence
• Animals
• Circular Dichroism
• Dose-Response Relationship, Drug
• Edema (chemically induced)
• Erythrocytes (drug effects)
• Guinea Pigs
• Hemolysis (drug effects)
• Intercellular Signaling Peptides and Proteins
• Lysine (metabolism)
• Peptides (chemistry, isolation & purification, toxicity)
• Rats
• Rats, Wistar
• Structure-Activity Relationship
• Tryptamines (metabolism)
• Wasp Venoms (chemistry, isolation & purification, toxicity)