Crotamine
Encyclopedia
Crotamine is a toxin
present in the venom
of the South America
n rattlesnake
(Crotalus durissus terrificus). It was first isolated and purified by Brazilian scientist José Moura Gonçalves
, and later intensively studied by his group of collaborators at the Medical School of Ribeirão Preto
of the University of São Paulo
(C.R. Laure, A. Haddad, F.L. De Lucca and J.R. Giglio, among others). It is a 42-long polypeptide containing 11 basic residues (9 lysine
s, 2 arginine
s) and 6 cysteine
s. It has also been isolated from the venom of North American prairie rattlesnake, Crotalus viridis viridis.
Crotamine has a number of biological actions: it acts on cell membrane's sodium channels, is slightly analgesic
and is myotoxic, i.e., it penetrates the cells of muscle
s and promotes necrosis
. Crotamine is homologous
with other venom myotoxin
s and is similar to α-,β-defensin
s.
The aminoacid sequence and the 3D molecular structure
of crotamine have already been determined.
YKQCHKKGGHCFPKEKICLPPSSDFGKMDCRWRWKCCKKGS—G
The gene
and chromosome
location responsible for its synthesis have been identified by the group led by Gandhi Rádis-Baptista, working at the Instituto Butantan
, in São Paulo, Brazil. The mRNA has about 340 nucleotide
s and codifies a pre-crotamine, including the signal peptide
, the mature crotamine, and a final lysine.
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
present in 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...
of the South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
n rattlesnake
Rattlesnake
Rattlesnakes are a group of venomous snakes of the genera Crotalus and Sistrurus of the subfamily Crotalinae . There are 32 known species of rattlesnake, with between 65-70 subspecies, all native to the Americas, ranging from southern Alberta and southern British Columbia in Canada to Central...
(Crotalus durissus terrificus). It was first isolated and purified by Brazilian scientist José Moura Gonçalves
José Moura Gonçalves
José Moura Gonçalves , Brazilian physician, biomedical scientist, biochemist and educator, one of the pioneers of biochemistry in the country....
, and later intensively studied by his group of collaborators at the Medical School of Ribeirão Preto
Faculdade de Medicina de Ribeirão Preto
Faculdade de Medicina de Ribeirão Preto is a medical school of the University of São Paulo located in the city of Ribeirão Preto, state of São Paulo, Brazil, founded 1952...
of the University of São Paulo
University of São Paulo
Universidade de São Paulo is a public university in the Brazilian state of São Paulo. It is the largest Brazilian university and one of the country's most prestigious...
(C.R. Laure, A. Haddad, F.L. De Lucca and J.R. Giglio, among others). It is a 42-long polypeptide containing 11 basic residues (9 lysine
Lysine
Lysine is an α-amino acid with the chemical formula HO2CCH4NH2. It is an essential amino acid, which means that the human body cannot synthesize it. Its codons are AAA and AAG....
s, 2 arginine
Arginine
Arginine is an α-amino acid. The L-form is one of the 20 most common natural amino acids. At the level of molecular genetics, in the structure of the messenger ribonucleic acid mRNA, CGU, CGC, CGA, CGG, AGA, and AGG, are the triplets of nucleotide bases or codons that codify for arginine during...
s) and 6 cysteine
Cysteine
Cysteine is an α-amino acid with the chemical formula HO2CCHCH2SH. It is a non-essential amino acid, which means that it is biosynthesized in humans. Its codons are UGU and UGC. The side chain on cysteine is thiol, which is polar and thus cysteine is usually classified as a hydrophilic amino acid...
s. It has also been isolated from the venom of North American prairie rattlesnake, Crotalus viridis viridis.
Crotamine has a number of biological actions: it acts on cell membrane's sodium channels, is slightly analgesic
Analgesic
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
and is myotoxic, i.e., it penetrates the cells of muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
s and promotes necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
. Crotamine is homologous
Homology (chemistry)
In chemistry, homology refers to the appearance of homologues. A homologue is a compound belonging to a series of compounds differing from each other by a repeating unit, such as a methylene group, a peptide residue, etcetera....
with other venom myotoxin
Myotoxin
Myotoxins are small, basic peptides found in snake venoms, such as in that of certain rattlesnakes. This involves a non-enzymatic mechanism that leads to severe muscle necrosis...
s and is similar to α-,β-defensin
Defensin
Defensins are small cysteine-rich cationic proteins found in both vertebrates and invertebrates. They have also been reported in plants. They are, and function as, host defense peptides. They are active against bacteria, fungi and many enveloped and nonenveloped viruses. They consist of 18-45 amino...
s.
The aminoacid sequence and the 3D molecular structure
Molecular structure
The molecular structure of a substance is described by the combination of nuclei and electrons that comprise its constitute molecules. This includes the molecular geometry , the electronic properties of the...
of crotamine have already been determined.
YKQCHKKGGHCFPKEKICLPPSSDFGKMDCRWRWKCCKKGS—G
The gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
and chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
location responsible for its synthesis have been identified by the group led by Gandhi Rádis-Baptista, working at the Instituto Butantan
Instituto Butantan
Instituto Butantan is a Brazilian biomedical research center affiliated to the São Paulo State Secretary of Health. It is located near the campus of the University of São Paulo, in the city of the same name.-History:...
, in São Paulo, Brazil. The mRNA has about 340 nucleotide
Nucleotide
Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...
s and codifies a pre-crotamine, including the signal peptide
Signal peptide
A signal peptide is a short peptide chain that directs the transport of a protein.Signal peptides may also be called targeting signals, signal sequences, transit peptides, or localization signals....
, the mature crotamine, and a final lysine.
External links
- Nucleotide sequence and translation for crotasin. Entrez Database. National Center for Biotechnology Information.