141:, a known probe used to indicate the presence of certain potassium channels, over binding to synaptic membranes within rat brains. The binding sites of the toxin between Kv1.1, Kv1.2, and Kv1.3 were found to include three common amino acid residues: Lys-25, Tyr-26, and Ser-23. This combination appear to form the core residues that are the site of binding of all Kv1 channel blockers from sea anemones. In particular with Kv1.1, the major reason for BgK's affinity towards binding to this specific channel stems from an electrostatic connections between the side chain of Lys-25 and the carbonyl oxygens of the amino acids found within the channel's molecular filter. Another aspect of BgK's binding to Kv1.1 involves the hydrophobic reactions between Tyr-379 of Kv1.1 and the dyad of Tyr-26 and Phe-6 formed within BgK. Such interactions have been found to surround the Lys-25 and could potentially strengthen the electrostatic interactions that can form between this specific lysine and the oxygen atoms of the channel's filter.
101:. All three of these toxins have an affinity to dendrotoxin sensitive potassium channels that are found within rat brain membranes. BgK and ShK attenuate K channels in the neurons of rat dorsal ganglia, in vitro. AsKs stops potassium channel currents that are present in Xenopus oocytes. These toxins potentially represent a new structural type of potassium channel inhibitor. Compared to the short and well-studied scorpion toxins, these anemone toxins have comparable amino acid content (35-37 residues) and the same number of disulfide bridges (three). However, these anemone toxins do not share any sequential similarity. Specifically, the different position of the cysteine residues found within these toxins suggests that BgK, ShK, and AsKS are a new family of toxins.
68:
BgK can be found in the mucus of the
Bunodosoma granulifera, a common sea anemone found along the coasts of Cuba. Since it is a contracting sea anemone, it has two forms based on the position of its tentacles: open and closed. BgK is released when the anemone is in the closed form, a position it
463:
Braud, S; Belin, P; Dassa, J; Pardo, L; Mourier, G; Caruana, A; Priest, BT; Dulski, P; Garcia, ML; Ménez, A; Boulain, J-C; Gasparini, S (2004). "BgK, a disulfide-containing sea anemone toxin blocking K+ channels, can be produced in
Escherichia coli cytoplasm as a functional tagged protein".
104:
The only homology BgK shares is with a double-headed protease inhibitor found in sea turtles, however it is only limited to a part of the inhibitor, with the largest similarity found with the cysteine residues, which compose six of the eight conserved amino acids found in the two sequences.
69:
assumes during the day or during times of agitation. In this form, the anemone’s tentacles retract, releasing a mucus from a fibrous matrix found in the mesoglea, a space between the ectodermis and the gastrodermis. For every gram of freeze-dried mucus, there is 0.5 mg BgK.
203:
Aneiros, A; García, I; Martínez, JR; Harvey, AL; Anderson, AJ; Marshal, DL; Engstöm, Å; Hellman, U; Karlsson, E (1993). "A potassium channel toxin from the secretion of the sea anemone "Bunodosoma granulifera". Isolation, amino acid sequence and biological activity".
176:
as a functional protein, exhibiting all of the effects on potassium channels found with BgK isolated from its natural source, there has been no research into any potential therapeutic purpose so far, with most of its use being for research on potassium channels.
160:) of BgK for mice is 4.5 ng per gram. Symptoms observed include trembling of the tail, muscle twitch, salivation, and paralysis, which are the generally observed physical manifestation of
424:"Structure of the BgK-Kv1.1 complex based on distance restraints identified by double mutant cycles. Molecular basis for convergent evolution of Kv1 channel blockers"
60:) of the specific sea anemone from which the toxin was found, and the K standing for the chemical symbol for potassium owing to its observed effects on K channels.
376:
Alessandri-Haber, N; Lecoq, A; Gasparini, S; Grangier-MacMath, G; Jacquet, G; Harvey, AL; de Meiros, G; Rowan, EG; Gola, M; Ménez, A; Crest, M (1999-12-10).
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channels with similar affinities. IC50 is 6 nM for Kv1.1, 15 nM for Kv1.2, and 10 nM for Kv1.3. Meanwhile, tests on the Kv3 channel, specifically
256:, an inhibitor for Kv1 channels — revision of the amino acid sequence, disulfide-bridge assignment, Chemical Synthesis, and Biological Activity"
295:
Castaneda, Olga; et al. (1995). "Characterization of a potassium channel toxin from the
Caribbean Sea anemone Stichodactyla helianthus".
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bonds. The neurotoxin belongs to a family of toxins found within 3 different sea anemones. The two other anemone/toxin combinations are:
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250:
Cotton, Joel; Crest, M; Bouet, F; Alessandri, N; Gola, M; Forest, E; Karlsson, E; Castañeda, O; Harvey, AL; Vita, C; Ménez, A (1997).
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378:"Mapping the functional anatomy of BgK on Kv1.1, Kv1.2, and Kv1.3. Clues to design analogs with enhanced selectivity"
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332:"Kalicludines and kaliseptine. Two different classes of sea anemone toxins for voltage sensitive K+ channels"
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Gilquin, B; Racape, J; Wrish, A; Visan, V; Lecoq, A; Grissmer, S; Ménez, A; Gasparini, S (2002-07-19).
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Schweitz, H; Bruhn, T; Guillemare, E; Moinier, E; Lancelin, JM; Béress, L; Lazdunski, M (1995).
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129:, show that the ion channel exhibits an insensitivity of up to 0.125 μM BgK.
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The neurotoxin was named BgK, with the Bg representing the Latin taxonomy (
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Biochimica et
Biophysica Acta (BBA) - General Subjects
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BgK is composed of 37 amino acid residues, and three
252:"A potassium channel toxin from the sea anemone
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26:found within secretions of the sea anemone
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273:10.1111/j.1432-1033.1997.00192.x
260:European Journal of Biochemistry
37:voltage-gated potassium channels
172:While BgK has been produced in
1:
309:10.1016/0041-0101(95)00013-C
218:10.1016/0304-4165(93)90082-J
39:, thus inhibiting neuronal
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521:Potassium channel blockers
162:potassium channel blockers
478:10.1016/j.pep.2004.07.011
395:10.1074/jbc.274.50.35653
349:10.1074/jbc.270.42.25121
84:Stichodactyla helianthus
441:10.1074/jbc.M206205200
254:Bunodosoma granulifera
137:BgK competes with I-α-
466:Protein Expr. Purif
516:Sea anemone toxins
511:Ion channel toxins
151:median lethal dose
64:Sources in Nature
16:Sea anemone toxin
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434:(40): 37406–13.
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174:Escherichia coli
94:Anemonia viridis
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168:Therapeutic Use
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113:BgK blocks the
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133:Mode of Action
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506:Neurotoxins
428:J Biol Chem
382:J Biol Chem
336:J Biol Chem
139:dendrotoxin
58:granulifera
33:granulifera
500:Categories
181:References
54:Bunodosoma
29:Bunodosoma
24:neurotoxin
79:disulfide
73:Chemistry
47:Etymology
486:15477084
450:12133841
404:10585444
145:Toxicity
358:7559645
317:7660365
297:Toxicon
282:9063464
226:8098956
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121:, and
109:Target
127:Kv3.1
123:Kv1.3
119:Kv1.2
115:Kv1.1
22:is a
482:PMID
446:PMID
400:PMID
354:PMID
313:PMID
278:PMID
222:PMID
210:1157
149:The
99:AsKs
97:and
87:and
474:doi
436:doi
432:277
390:doi
386:274
344:doi
340:270
305:doi
268:doi
264:244
214:doi
89:ShK
20:BgK
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157:50
155:LD
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