Tetrahedron
Letters
Tetrahedron Letters 45 (2004) 5371–5373
Structure and enantioselective synthesis of polyamine toxin
MG30 from the venom of the spider Macrothele gigas
Nahoko Yamaji,a,* Manabu Horikawa,a Gerardo Corzo,a Hideo Naoki,a Joachim Haupt,b
Terumi Nakajimaa and Takashi Iwashitaa
aSuntory Institute for Bioorganic Research, Instrumental analysis, 1-1-1 Wakayamadai,
Shimamoto-Cho, Mishima-Gun, Osaka 618-8503, Japan
bInstitute of Ecology, Technical University Berlin, 10623 Berlin, Germany
Received 13 April 2004; revised 12 May 2004; accepted 17 May 2004
Abstract—A novel polyamine toxin, named MG30, was isolated from the venom of the spider, Macrothele gigas, and its structure
was elucidated by two-dimensional NMR and mass analysis. In addition, the enantioselective synthesis of MG30 was achieved to
assign its absolute stereochemistry.
ꢀ 2004 Elsevier Ltd. All rights reserved.
1. Introduction
2. Results
Spider venom contains various kinds of compounds such
as proteins, peptides and polyamine toxins. These toxins
are of interest as tools for studying neurophysiology and
pharmacology. Particularly, polyamine toxins have
shown specific activity as glutamate receptor blockers.1–3
M. gigas venom was obtained by electrical stimulation
of field-collected spiders from the Sonai area in Irio-
mote, Japan. The crude venom was frozen and stored at
)20 ꢁC until use.
The crude venom (70 lL) was resuspended in 0.1%
aqueous trifluoroacetic acid (TFA) containing 10%
acetonitrile, and the insoluble materials were removed
by centrifugation at 14,000g for 5 min. The supernatant
was purified by the established high-performance liquid
chromatography method (C18 / 10 · 250 mm, linear
gradient with 0–60% acetonitrile/H2O in 0.1% TFA in
60 min, flow rate 2.0 mL/min, UV detection at 220 nm).
The polyamine, named MG30, was a major component
of the venom to yield 150 lg.
In the previous report, we described six peptide toxins
(Magi 1–6), isolated from the venom of the Hexathe-
lidae spider Macrothele gigas collected at Iriomote-
Island in Japan.4 We have also isolated an unknown
polyamine compound, named MG30, as a major com-
ponent of the same spider venom. We report here the
structure determination of MG30 using two-dimen-
sional NMR, MS analysis and the enantioselective
synthesis of (R) and (S)-MG30 to assign the absolute
configuration of the native MG30.
1
The H NMR spectrum of MG30 showed peculiar sig-
nals to an indole ring at the low-field region (H-1, 3, 4, 5
16 ,1 7
21 ,2 2
1
O
and 6). H–1H COSY, TOCSY and HMBC analysis of
3
6
12
8
7
2
10
N
NH2
MG30 easily gave the structural information on an
indole-3-lactyl part, and the HMBC peaks from H-12
(dH 3.05 and 3.17) to C-11 (dC 178.8) revealed that an-
other unit connected to the indole-3-lactyl moiety
N
4
9
N
H
15
18
20
23
25
5
1
OH
N
H
MG30 (1)
1
through an amide linkage. H–1H COSY spectra led to
the connectivities from C-12 to C-15, C-18 to C-20 and
C-23 to C-25. This was also supported by TOCSY and
HMBC data. The methyl protons of H-16, 17, 21 and 22
(dH 2.98 and 3.17) had cross-peaks with dC 53.2 or 53.3
Keywords: Spider; Polyamine toxin; Macrothele gigas.
* Corresponding author. Tel.: +81-75-962-6142; fax: +81-75-962-2115;
0040-4039/$ - see front matter ꢀ 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2004.05.076