Isolation and characterization of myrmexins, six isoforms of venom proteins with anti-inflammatory activity from the tropical ant, Pseudomyrmex triplarinus

• Published in: Toxicon (Oxford) 2000-10, Vol.38 (10), p.1403-1413
• Main Authors: Pan, Jingzhi, Hink, W.F.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; amino acid sequences; animal proteins; Animals; Ant Venoms - chemistry; Ant Venoms - isolation & purification; Ant Venoms - pharmacology; Anti-Inflammatory Agents - isolation & purification; Anti-Inflammatory Agents - pharmacology; biochemical polymorphism; Carrageenan; Chromatography, High Pressure Liquid; Edema - chemically induced; Edema - prevention & control; Electrophoresis, Polyacrylamide Gel; Formicidae; high performance liquid chromatography; Hindlimb - drug effects; Hindlimb - pathology; inflammation; inhibition; Male; mass spectrometry; Molecular Sequence Data; molecular weight; myrmexins; polyacrylamide gel electrophoresis; Pseudomyrmex triplarinus; Rats; Rats, Sprague-Dawley; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Tropical Climate; venoms
• ISSN: 0041-0101; 1879-3150
• DOI: 10.1016/S0041-0101(99)00233-0

Venom from the tropical ant, Pseudomyrmex triplarinus, has anti-inflammatory properties demonstrated by the carrageenin-induced edema animal mode. A multi-protein complex that inhibits edema was isolated from the venom and was further characterized by high performance liquid chromatography (HPLC), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) and amino acid sequencing. Although the complex exhibited a single band in SDS-PAGE electrophoresis, six proteins (isoforms) were resolved and purified to homogeneity and were designated myrmexin I–VI. They have very similar molecular masses between 6998 and 7142 Da. Each myrmexin is a heterodimer consisting of a small subunit (SS1 or SS2 or SS3) disulfide-linked to a larger, quite structurally unrelated subunit (LS1 or LS2). Thus, the myrmexin complex consists of six isoforms of venom proteins: myrmexin I (SS1/LS2), myrmexin II (SS1/LS1), myrmexin III (SS2/LS2), myrmexin IV (SS3/LS2), myrmexin V (SS2/LS1), myrmexin VI (SS3/LS1). Subunit SS1 is highly homologous to SS2 (96% of identity) and SS3 (87% of identity) and LS1 is highly homologous to LS2 (79% of identity). Our study suggests that myrmexins may represent a new class of anti-inflammatory proteins.