PEPTIDOMIC CHARACTERIZATION OF THE VENOM FROM

PEPTIDOMIC CHARACTERIZATION OF THE VENOM FROM THE
COLOMBIAN SCORPION Centruroides margaritatus
Guerrero-Vargas, J.A .1,2, Fontes, W.1, Sousa, M.V.1, Castro, M.S.1,3
1
Centro Brasileiro de Serviços e Pesquisas em Proteínas, Instituto de Ciências
Biológicas, Universidade de Brasília, Brasília/DF, Brasil; 2 Grupo de
Investigaciones Herpetológicas y Toxinológicas, Universidad del Cauca,
Popayán, Colombia; 3Laboratório de Toxinologia Instituto de Ciências
Biológicas, Universidade de Brasília/DF, Brasil
Scorpion venoms are a complex mixture of peptides that exert their
action via ion-channel modulation in biological membranes. In the present
report we describe the first peptidomic characterization of the venom from the
Colombian scorpion Centruroides margaritatus. This species is capable of
producing moderate accidents and serious complications in humans, but little
information is available related to its components. The crude venom was
fractioned by RP-HPLC using a C8 column (4.6 x 250 mm) and 43 fractions
were collected and vacuum dried. All these fractions were analyzed by
MALDI-TOF MS and 91 distinct compounds had their molecular masses
characterized. The venom of C. margaritatus exhibits 54% of their toxins in the
molecular mass range from 2.5 to 6.0 kDa that probably includes short-chain K+
channel blockers; 13% of the total are in the range from 6.5 to 8.0 kDa and may
include long-chain Na + channel toxins. Finally, 33% of the components present
in C. margaritatus venom are peptides smaller than 2.0 KDa, a group rarely
described in scorpions venoms. Two purified peptides with molecular masses of
2.6 kDa and 3.3 kDa were sequenced using automated Edman degradation.
The first toxin was called MgTx2 and exhibits similarities to other scorpions
K+-blocking neurotoxins, and the second peptide was called MgTx3 and no
significant sequence similarity to other neurotoxins was detected.
KEYWORDS
Scorpion, Centruroides margaritatus, Colombia, MALDI-TOF/MS, Peptidomic
characterization, Edman degradation.
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