Triflin
Encyclopedia
Triflin is a cysteine-rich secretory protein
(CRISP), which is excreted by the venom
gland of the Habu snake (Trimeresurus flavoviridis
). Triflin reduces high potassium-induced smooth muscle contraction, suggesting a blocking effect on L-type calcium channel
s.
Triflin is a toxin derived from snake venom. The toxin is produced in the gland of the Habu snake, Trimeresurus flavoviridis
.
Triflin weighs 25 kDa and consists of 221 amino-acid residues.
The first 163 residues of the N-teminal domain forms an α-β-α sandwich core. This domain is comparable with group 1 plant pathogenesis-related protein
(PR-1).
The C-terminal domain, has five disulfide bridges
. This domain is responsible for the selectivity of the protein and consists of two subdomains: N-terminal subdomain (Cys 167 to Cys 179) and C-terminal subdomain (42 amino-acids residues).
The N-terminal subdomain is connected with N-terminal domain through two main-chain hydrogen bond
s between β11 and β2 and is thereby part of the PR-1 domain.
The C-terminal subdomain is stabilized by three disulfide bridges and it is remarkable that this domain does not interact with either the PR-1 domain or the N-terminal sub-domain. The C-terminal subdomain consists of particles, including some hydrophobic residues that are exposed to the solvent. These hydrophobic residues might mediate the interaction with the target proteins and therefore receptor recognition.
There are some homologous toxins to Triflin with different percentages of amino-acid sequence similarity, such as Ablomin
, Latisemin
, Stecrip (88%), Helothermine (49%), Pseudechetoxin (62%), Pseudesin (61%). The snake venoms which belong to CRISP family seem to be homologous to each other, however there are differences in their protein targets.
s.
itself, has high affinity for Triflin, and may thus work as a defensive mechanism against accidental self-poisoning, suggesting a possible role for SSP-2 as an antidote to triflin.
Cysteine-rich secretory protein
Cysteine-rich secretory proteins, often abbreviated as CRISPs, are a group of glycoproteins found exclusively in vertebrates. They are a subgroup of the CRISP, antigen 5 and Pr-1 protein superfamily and are substantially implicated in the functioning of the mammalian reproductive system...
(CRISP), which is excreted by the venom
Venom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...
gland of the Habu snake (Trimeresurus flavoviridis
Trimeresurus flavoviridis
Trimeresurus flavoviridis is a venomous pitviper species found in Japan in the Ryukyu Islands. No subspecies are currently recognized.-Description:...
). Triflin reduces high potassium-induced smooth muscle contraction, suggesting a blocking effect on L-type calcium channel
L-type calcium channel
The L-type calcium channel is a type of voltage-dependent calcium channel. "L" stands for long-lasting referring to the length of activation. Like the others of this class, the α1 subunit is the one that determines most of the channel's properties....
s.
Source
Trimeresurus flavoviridis
Trimeresurus flavoviridis is a venomous pitviper species found in Japan in the Ryukyu Islands. No subspecies are currently recognized.-Description:...
.
Chemistry
Triflin is a cysteine-rich secretory protein, which means it belongs to the CRISP family. This is a group of single chain polypeptides found in various organisms.Triflin weighs 25 kDa and consists of 221 amino-acid residues.
The first 163 residues of the N-teminal domain forms an α-β-α sandwich core. This domain is comparable with group 1 plant pathogenesis-related protein
Pathogenesis-related protein
Pathogenesis-related proteins are proteins produced in plants in the event of a pathogen attack. They are induced as part of systemic acquired resistance.Many proteins found in wine are grape pathogen-related proteins...
(PR-1).
The C-terminal domain, has five disulfide bridges
Disulfide bond
In chemistry, a disulfide bond is a covalent bond, usually derived by the coupling of two thiol groups. The linkage is also called an SS-bond or disulfide bridge. The overall connectivity is therefore R-S-S-R. The terminology is widely used in biochemistry...
. This domain is responsible for the selectivity of the protein and consists of two subdomains: N-terminal subdomain (Cys 167 to Cys 179) and C-terminal subdomain (42 amino-acids residues).
The N-terminal subdomain is connected with N-terminal domain through two main-chain hydrogen bond
Hydrogen bond
A hydrogen bond is the attractive interaction of a hydrogen atom with an electronegative atom, such as nitrogen, oxygen or fluorine, that comes from another molecule or chemical group. The hydrogen must be covalently bonded to another electronegative atom to create the bond...
s between β11 and β2 and is thereby part of the PR-1 domain.
The C-terminal subdomain is stabilized by three disulfide bridges and it is remarkable that this domain does not interact with either the PR-1 domain or the N-terminal sub-domain. The C-terminal subdomain consists of particles, including some hydrophobic residues that are exposed to the solvent. These hydrophobic residues might mediate the interaction with the target proteins and therefore receptor recognition.
There are some homologous toxins to Triflin with different percentages of amino-acid sequence similarity, such as Ablomin
Ablomin
Ablomin is a toxin present in the venom of the Japanese Mamushi snake, which blocks L-type voltage-gated calcium channels.- Etymology :The protein ablomin is a component of the venom of the Japanese Mamushi snake, Gloydius blomhoffi...
, Latisemin
Latisemin
Latisemin is a cysteine-rich secretory protein that can be isolated from the venom of the Black-banded sea krait, a sea snake indigineous to the warmer waters of the western Pacific Ocean...
, Stecrip (88%), Helothermine (49%), Pseudechetoxin (62%), Pseudesin (61%). The snake venoms which belong to CRISP family seem to be homologous to each other, however there are differences in their protein targets.
Target
Triflin reduces high potassium induced smooth muscle contraction, suggesting a blocking effect on L-type calcium channelL-type calcium channel
The L-type calcium channel is a type of voltage-dependent calcium channel. "L" stands for long-lasting referring to the length of activation. Like the others of this class, the α1 subunit is the one that determines most of the channel's properties....
s.
Treatment
One of the small serum proteins (SSP-2), a substance produced by Trimeresurus flavoviridisTrimeresurus flavoviridis
Trimeresurus flavoviridis is a venomous pitviper species found in Japan in the Ryukyu Islands. No subspecies are currently recognized.-Description:...
itself, has high affinity for Triflin, and may thus work as a defensive mechanism against accidental self-poisoning, suggesting a possible role for SSP-2 as an antidote to triflin.
See also
- Other snake venom proteins in the CRISP family:
- PiscivorinPiscivorinPiscivorin is a component of snake venom secreted by the Eastern Cottonmouth . It is a member of the cysteine-rich secretory protein family, which blocks voltage-dependent calcium channels.- Etymology :...
from the Eastern Cottonmouth - LatiseminLatiseminLatisemin is a cysteine-rich secretory protein that can be isolated from the venom of the Black-banded sea krait, a sea snake indigineous to the warmer waters of the western Pacific Ocean...
from the Erabu snake - AblominAblominAblomin is a toxin present in the venom of the Japanese Mamushi snake, which blocks L-type voltage-gated calcium channels.- Etymology :The protein ablomin is a component of the venom of the Japanese Mamushi snake, Gloydius blomhoffi...
from the Mamushi snake - OphaninOphaninOphanin is a toxin found in the venom of the King Cobra , which lives throughout South East Asia. This toxin belongs to the cysteine-rich secretory protein family...
from the King Cobra
- Piscivorin