Mastoparans

Introduction

Mastoparans, first isolated from the venom of the wasp Vespula lewisii, owe the name to its function as a mast cell degranulating peptide. Mastoparans are a group of amphiphilic tetradecapeptides found to be the major component of wasp venoms. They were originally discovered as the agents that induce histamine release from mast cells and later found to possess a variety of biological activities, for instance, induction of degranulation and histamine release of mast cells, and activation of phospholipase A2, phospholipase C, G proteins, and guanylate cyclase. In addition, Mastoparans exhibit potent antimicrobial activity. Some of them also show hemolytic activity.

Mechanism of action

The biological activities of mastoparans have been ascribed to their ability to interact with the cell membrane surface, G proteins and calmodulin via the positively charged side of their amphipathic α-helical structure and these activities are associated with some types of post-transcriptional processing of their precursors, such as C-terminal amidation. This also occurs with other peptides, such as melittin, clavanin or penaeidins, etc. There are studies showing an increase in activity following amidation or, alternatively, an activity decrease when the amide is removed.

Application of Mastoparans

Owing to the emergence of antibiotic-resistant pathogenic bacteria, antimicrobial peptides have attracted more attention to be developed as a new class of antimicrobial agents. One study shows that MPs exhibit the effective antimicrobial activity against many bacteria at 32 μg/ml, but this concentration causes only slight hemolytic effects on the mammalian erythrocytes, implying that it is possible to be used in therapeutic application against microbial pathogens; in particular, used to treat sheep bacterial infection because MPs almost cause no damage to sheep erythrocytes even at a high concentration at 256 μg/ml. In addition, a number of discoveries have been made regarding the functions of this molecule in vivo and in vitro and it is known to act as an antitumor, cytolitic and insulinotropic agent.

References

1. ShengQuan Liu, FengWang, LinTang, WenJun Gui, Peng Cao, XiaoQin Liu, Alice Wing-Sem Poon, Pang-Chui Shaw, &Tao Jiang(2007). Crystal structure of mastoparan from Polistes jadwagae at 1.2 Å resolution. Journal of Structural Biology, 160(1), 28-34.
2. Chun-Hsien Lin, Jason T.C. Tzen, Ching-Lin Shyu, Mars J. Yang, &Wu-Chun Tu (2011). Structural and biological characterization of mastoparans in the venom of Vespa species in Taiwan. Peptides, 32(10), 2027-2036.