328
9 Toxic Proteins and Peptides
[74]. A toxin isolated from the snail-hunting species C. textile corresponds to the w-conotoxins of
the piscivore species in the position of the cysteine residues but is only effective against snails and
crustaceans [21].
The proboscis of many nemertines is equipped
with poison glands. In the hoplonemertines,
where the proboscis bears a stiletto, the glands
produce low molecular weight toxins. Only in the
case of the North Atlantic heteronemertine
Cerebratulus lacteus have toxic proteins been examined in detail and partly sequenced. Two groups
of small toxic proteins are found: the three A toxins consist of 93-98 amino acids and are strongly
cytolytic; toxin A-III, for example, is fourfold
more active than melittin in the haemolysis of
human blood. The four B toxins are significantly
smaller (49-56 amino acids) and have neurotoxin
activity, although only against crustacean neurons
[31]. The poison in the nematocysts of some Cnidarla is extraordinarily toxic with LDso values
against crustaceans of 1-2 flg/kg. Certain species,
e.g. the sea wasp Chironex fleckeri (Cubozoa),
can be dangerous for humans. The venom is again
a mixture of various pharmacologically or enzymatically active components. The acute pain arising from contact with the sea nettle Chrysaora is
produced by histamine, serotonin, prostaglandins
E and F, and kinin-like peptides [20]. The toxins
isolated from the nematocysts of different jellyfish vary greatly in both their action and structure;
they include proteins and peptides, ranging in size
from 3 to 240 kDa, which have cardio-, neuro- or
myotoxic activities. The best investigated are the
neurotoxins of the sea anemones, all of which act
by retarding the inactivation of sodium channels.
The proteins may be divided, according to structure, into at least two classes; within each class
they are homologous. One such class contains
proteins of 44-47 amino acids and includes, for
example, the components AsI, AsII and AsV of
Anemone sulcata, AxI of Anthopleura xanthogrammica, and RpII and RpIII from Radianthus
paumatoensis (Fig. 9.4c). A second class includes
peptides with a maximum of 31 amino acids, such
as AsIII and a toxin isolated from Parasicyonis
actinostoloides [45, 49,56]. The lethal haemolytic
toxins of various sea anemones have a different
sort of structure, e.g. cytolysin I-IV from Stoichactis helianthus (153-160 amino acids), tenebrosin C from Actinia tenebrosa (179 amino acids)
and equinatoxin from A. equina, but are very
similar to each other in sequence [61]. The main
constituent of the poison obtained from isolated
nematocysts of the Portuguese man-of-war Physalia physalis (Siphonophora) is a haemolytic glycoprotein of 240 kDa, composed of three different, as yet unsequenced, polypeptides of 125, 53
and 34 kDa.
References
1. Adams M. E. et al.: Omega-agatoxins: Novel calcium
channel antagonists of two subtypes from funnel web
spider (Agelenopsis aperta) venom. J. BioI. Chern.
265: 861-867 (1990)
2. Aird S. D. et al.: The amino acid sequence of the
acidic subunit B-chain of crotoxin. Biochim. biophys.
Acta 1040: 217-224 (1990)
3. Argiolas A. and Pisano J. J.: Bombolitins, a new class
of mast cell degranulating pep tides from the venom of
the bumblebee Megabombus pennsylvanicus. J. bioI.
Chern. 260: 1437-44 (1985)
4. Barra D. et al.: Rohdei-litorin: a new peptide from the
skin of Phyllomedusa rohdei. FEBS Letters 182: 53-56
(1985)
5. Bettini S. (ed.): Arthropod venoms. Hb. expo Pharmacol. Vol. 48. Springer, Berlin 1978
6. Bjarnason J. B. and Fox J. W.: Characterization of two
hemorrhagic zinc proteinases, toxin c and toxin d, from
western diamondback rattlesnake (Crotalus atrox)
venom. Biochim. biophys. Acta 911: 356-363 (1987)
7. Bouchier C. et al.: Cloning and sequencing of cDNAs
encoding the two subunits of crotoxin. Nucleic Acids
Res. 16: 9050 (1988)
8. Bougis P. E., Rochat H. and Smith L. A.: Precursors
of Androctonus australis scorpion neurotoxins. J. BioI.
Chern. 264: 19259-65 (1989)
9. Breckenridge R. and Dufton M. J.: The structural
evolution of cobra venom cytotoxins. J. mol. Evol. 26:
274-283 (1987)
10. Brown M. R. et al.: Amino acid sequence of versutoxin, a lethal neurotoxin from the venom of the funnel-web spider Atrax versutus. Biochem. J. 250:
401-405 (1988)
11. Corfield P. W R., Lee T. J. and Low B. W: The crystal
structure of erabutoxin a at 2.0 A resolution. J. BioI.
Chern. 264: 9239-42 (1989)
12. Dotimas E. M. et al.: Isolation and structure analysis
of bee venom mast cell degranulating peptide. Biochim. biophys. Acta 911: 285-293 (1987)
13. Dufton M. J.: Classification of elapid snake neurotoxins and cytotoxins according to chain length: evolutionary implications. J. mol. Evol. 20: 128-134 (1984)
14. Eitan M. et al.: A scorpion venom neurotoxin paralytic
to insects that affects sodium current inactivation:
Purification, primary structure, and mode of action.
Biochemistry 29: 5941-47 (1990)
15. Eng J. et al.: Purification and structure of exendin-3, a
new pancreatic secretagogue isolated from Heloderma
horridum venom. J. BioI. Chern. 265: 20259-62 (1990)
16. Erspamer V. et al.: Amino acid composition and
sequence of Crinia-angiotensin, an angiotensin-II-like
endecapeptide from the skin of the Australian frog Crinia georgiana. Experientia 35: 1132-33 (1979)
17. Farid T. M., Tu A. T. and EI-Asmar E: Characterization of cerastobin, a thrombin-like enzyme from Cerastes vipera. Biochemistry 28: 371-377 (1989)
9 Toxic Proteins and Peptides
[74]. A toxin isolated from the snail-hunting species C. textile corresponds to the w-conotoxins of
the piscivore species in the position of the cysteine residues but is only effective against snails and
crustaceans [21].
The proboscis of many nemertines is equipped
with poison glands. In the hoplonemertines,
where the proboscis bears a stiletto, the glands
produce low molecular weight toxins. Only in the
case of the North Atlantic heteronemertine
Cerebratulus lacteus have toxic proteins been examined in detail and partly sequenced. Two groups
of small toxic proteins are found: the three A toxins consist of 93-98 amino acids and are strongly
cytolytic; toxin A-III, for example, is fourfold
more active than melittin in the haemolysis of
human blood. The four B toxins are significantly
smaller (49-56 amino acids) and have neurotoxin
activity, although only against crustacean neurons
[31]. The poison in the nematocysts of some Cnidarla is extraordinarily toxic with LDso values
against crustaceans of 1-2 flg/kg. Certain species,
e.g. the sea wasp Chironex fleckeri (Cubozoa),
can be dangerous for humans. The venom is again
a mixture of various pharmacologically or enzymatically active components. The acute pain arising from contact with the sea nettle Chrysaora is
produced by histamine, serotonin, prostaglandins
E and F, and kinin-like peptides [20]. The toxins
isolated from the nematocysts of different jellyfish vary greatly in both their action and structure;
they include proteins and peptides, ranging in size
from 3 to 240 kDa, which have cardio-, neuro- or
myotoxic activities. The best investigated are the
neurotoxins of the sea anemones, all of which act
by retarding the inactivation of sodium channels.
The proteins may be divided, according to structure, into at least two classes; within each class
they are homologous. One such class contains
proteins of 44-47 amino acids and includes, for
example, the components AsI, AsII and AsV of
Anemone sulcata, AxI of Anthopleura xanthogrammica, and RpII and RpIII from Radianthus
paumatoensis (Fig. 9.4c). A second class includes
peptides with a maximum of 31 amino acids, such
as AsIII and a toxin isolated from Parasicyonis
actinostoloides [45, 49,56]. The lethal haemolytic
toxins of various sea anemones have a different
sort of structure, e.g. cytolysin I-IV from Stoichactis helianthus (153-160 amino acids), tenebrosin C from Actinia tenebrosa (179 amino acids)
and equinatoxin from A. equina, but are very
similar to each other in sequence [61]. The main
constituent of the poison obtained from isolated
nematocysts of the Portuguese man-of-war Physalia physalis (Siphonophora) is a haemolytic glycoprotein of 240 kDa, composed of three different, as yet unsequenced, polypeptides of 125, 53
and 34 kDa.
References
1. Adams M. E. et al.: Omega-agatoxins: Novel calcium
channel antagonists of two subtypes from funnel web
spider (Agelenopsis aperta) venom. J. BioI. Chern.
265: 861-867 (1990)
2. Aird S. D. et al.: The amino acid sequence of the
acidic subunit B-chain of crotoxin. Biochim. biophys.
Acta 1040: 217-224 (1990)
3. Argiolas A. and Pisano J. J.: Bombolitins, a new class
of mast cell degranulating pep tides from the venom of
the bumblebee Megabombus pennsylvanicus. J. bioI.
Chern. 260: 1437-44 (1985)
4. Barra D. et al.: Rohdei-litorin: a new peptide from the
skin of Phyllomedusa rohdei. FEBS Letters 182: 53-56
(1985)
5. Bettini S. (ed.): Arthropod venoms. Hb. expo Pharmacol. Vol. 48. Springer, Berlin 1978
6. Bjarnason J. B. and Fox J. W.: Characterization of two
hemorrhagic zinc proteinases, toxin c and toxin d, from
western diamondback rattlesnake (Crotalus atrox)
venom. Biochim. biophys. Acta 911: 356-363 (1987)
7. Bouchier C. et al.: Cloning and sequencing of cDNAs
encoding the two subunits of crotoxin. Nucleic Acids
Res. 16: 9050 (1988)
8. Bougis P. E., Rochat H. and Smith L. A.: Precursors
of Androctonus australis scorpion neurotoxins. J. BioI.
Chern. 264: 19259-65 (1989)
9. Breckenridge R. and Dufton M. J.: The structural
evolution of cobra venom cytotoxins. J. mol. Evol. 26:
274-283 (1987)
10. Brown M. R. et al.: Amino acid sequence of versutoxin, a lethal neurotoxin from the venom of the funnel-web spider Atrax versutus. Biochem. J. 250:
401-405 (1988)
11. Corfield P. W R., Lee T. J. and Low B. W: The crystal
structure of erabutoxin a at 2.0 A resolution. J. BioI.
Chern. 264: 9239-42 (1989)
12. Dotimas E. M. et al.: Isolation and structure analysis
of bee venom mast cell degranulating peptide. Biochim. biophys. Acta 911: 285-293 (1987)
13. Dufton M. J.: Classification of elapid snake neurotoxins and cytotoxins according to chain length: evolutionary implications. J. mol. Evol. 20: 128-134 (1984)
14. Eitan M. et al.: A scorpion venom neurotoxin paralytic
to insects that affects sodium current inactivation:
Purification, primary structure, and mode of action.
Biochemistry 29: 5941-47 (1990)
15. Eng J. et al.: Purification and structure of exendin-3, a
new pancreatic secretagogue isolated from Heloderma
horridum venom. J. BioI. Chern. 265: 20259-62 (1990)
16. Erspamer V. et al.: Amino acid composition and
sequence of Crinia-angiotensin, an angiotensin-II-like
endecapeptide from the skin of the Australian frog Crinia georgiana. Experientia 35: 1132-33 (1979)
17. Farid T. M., Tu A. T. and EI-Asmar E: Characterization of cerastobin, a thrombin-like enzyme from Cerastes vipera. Biochemistry 28: 371-377 (1989)