Agelenin

Agelenin

Names
Other names U1-agatoxin-Aop1a, U1-AGTX-Aop1a
Identifiers
3D model (JSmol)	Interactive image
ChemSpider	none
KEGG	C20115
InChI InChI=1S/C160H259N51O46S6/c1-14-82(12)126(155(254)197-99(55-85-61-176-88-32-19-18-31-87(85)88)141(240)195-103(59-125(224)225)144(243)202-108(68-214)145(244)186-92(36-25-45-174-159(168)169)133(232)205-113(73-261)150(249)199-105(157(256)257)53-81(10)11)209-146(245)109(69-215)203-139(238)97(51-79(6)7)191-135(234)94(40-41-124(222)223)188-130(229)89(33-20-22-42-161)187-148(247)111(71-259)204-132(231)90(34-21-23-43-162)184-137(236)95(49-77(2)3)182-122(220)64-178-128(227)106(66-212)201-151(250)114(74-262)208-152(251)115(75-263)206-134(233)93(37-26-46-175-160(170)171)189-153(252)116-38-27-47-210(116)123(221)65-179-129(228)107(67-213)200-138(237)96(50-78(4)5)190-127(226)83(13)181-136(235)101(57-118(164)216)194-149(248)112(72-260)207-140(239)98(54-84-29-16-15-17-30-84)192-131(230)91(35-24-44-173-158(166)167)185-143(242)102(58-119(165)217)193-142(241)100(56-86-62-172-76-180-86)196-154(253)117-39-28-48-211(117)156(255)104(52-80(8)9)198-147(246)110(70-258)183-121(219)63-177-120(218)60-163/h15-19,29-32,61-62,76-83,89-117,126,176,212-215,258-263H,14,20-28,33-60,63-75,161-163H2,1-13H3,(H2,164,216)(H2,165,217)(H,172,180)(H,177,218)(H,178,227)(H,179,228)(H,181,235)(H,182,220)(H,183,219)(H,184,236)(H,185,242)(H,186,244)(H,187,247)(H,188,229)(H,189,252)(H,190,226)(H,191,234)(H,192,230)(H,193,241)(H,194,248)(H,195,240)(H,196,253)(H,197,254)(H,198,246)(H,199,249)(H,200,237)(H,201,250)(H,202,243)(H,203,238)(H,204,231)(H,205,232)(H,206,233)(H,207,239)(H,208,251)(H,209,245)(H,222,223)(H,224,225)(H,256,257)(H4,166,167,173)(H4,168,169,174)(H4,170,171,175)/t82-,83-,89-,90-,91-,92-,93-,94-,95-,96-,97-,98-,99-,100-,101-,102-,103-,104-,105-,106-,107-,108-,109-,110-,111-,112-,113-,114-,115-,116-,117-,126-/m0/s1 Key: ZUAKRHLBADVPFO-XJXDTQAOSA-N
SMILES NCC(=O)NCC(=O)N[C@@]([H])(CS)C(=O)N[C@@]([H])(CC(C)C)C(=O)N1[C@@]([H])(CCC1)C(=O)N[C@@]([H])(CC1=CN=C-N1)C(=O)N[C@@]([H])(CC(=O)N)C(=O)N[C@@]([H])(CCCNC(=N)N)C(=O)N[C@@]([H])(Cc1ccccc1)C(=O)N[C@@]([H])(CS)C(=O)N[C@@]([H])(CC(=O)N)C(=O)N[C@@]([H])(C)C(=O)N[C@@]([H])(CC(C)C)C(=O)N[C@@]([H])(CO)C(=O)NCC(=O)N1[C@@]([H])(CCC1)C(=O)N[C@@]([H])(CCCNC(=N)N)C(=O)N[C@@]([H])(CS)C(=O)N[C@@]([H])(CS)C(=O)N[C@@]([H])(CO)C(=O)NCC(=O)N[C@@]([H])(CC(C)C)C(=O)N[C@@]([H])(CCCCN)C(=O)N[C@@]([H])(CS)C(=O)N[C@@]([H])(CCCCN)C(=O)N[C@@]([H])(CCC(=O)O)C(=O)N[C@@]([H])(CC(C)C)C(=O)N[C@@]([H])(CO)C(=O)N[C@@]([H])([C@]([H])(CC)C)C(=O)N[C@@]([H])(CC(=CN2)C1=C2C=CC=C1)C(=O)N[C@@]([H])(CC(=O)O)C(=O)N[C@@]([H])(CO)C(=O)N[C@@]([H])(CCCNC(=N)N)C(=O)N[C@@]([H])(CS)C(=O)N[C@@]([H])(CC(C)C)C(=O)O
Properties
Molar mass	3500 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Agelenin (toxicologically named as U₁-agatoxin-Aop1a[1] and abbreviated as U₁-AGTX-Aop1a) is a neurotoxic peptide isolated from the venom of the spider Allagelena opulenta which consists of 35 amino acids. It is an antagonist of the presynaptic P-type calcium channel in insects.

Sources

Agelenin is an insecticidal toxin of the venom of the species Allagelena opulenta.[1] It was first discovered in 1990.[2]

Chemistry

Agelenin consists of a polypeptide chain of 35 amino acid residues.[2] It has a short anti-parallel β-sheet connected by three disulfide bonds and four β-turns that form the compact core structure. The three amino acid residues that are thought to be essential for the inhibiting activity of agelenin are Phe9, Ser28 and Arg33.[3]

The structure of agelenin is similar to the structure of ICK toxins like ω-Aga-IVA and ω-ACTXHv1a in that they all consist of three disulfide bonds with the same bonding pattern. An important difference between agelenin and ω-Aga-IVA and ω-ACTXHv1a is that ω-Aga-IVA and ω-ACTXHv1a have functional C-terminal tails.[3]

Agelenin belongs to toxin group of agatoxins.[1] The amino acid structure of agelenin is Gly-Gly-Cys-Leu-Pro-His-Asn-Arg-Phe-Cys-Asn-Ala-Leu-Ser-Gly-Pro-Arg-Cys-Cys-Ser-Gly-Leu-Lys-Cys-Lys-Glu-Leu-Ser-Ile-Trp-Asp-Ser-Arg-Cys-Leu (GGCLPHNRFCNALSGPRCCSGLKCKELSIWDSRCL).[3]

Target

Agelenin is directed against P-subtype calcium channels in insects.[4]

Toxicity

Agelenin is not toxic in mammals, but has a PD₅₀ of 291 pmol/g in crickets where it causes rapid, reversible paralysis.[3] In preparations of neuromuscular junctions of lobsters agelenin causes a non-reversible paralysis due to the suppression of excitatory postsynaptic potentials, presumably by inhibition of the presynaptic calcium influx.[2]

References

1. Institute for Molecular Bioscience. (2010) “U₂-agatoxin-Aop1a”, Arachnoserver. Accessed on: 11 October 2015.
2. Hagiwara, K., Sakai, T., Miwa, A., Kawai, N. and Nakajima, T. (1990). "Complete amino acid sequence of a new type of neurotoxin from the venom of the spider, Agelena opulenta". BioMed Research International. 11: 181–186. doi:10.2220/biomedres.11.181.
3. Yamaji, N., Sugase, K., Nakajima, T., Miki, T., Wakamori, M., More, Y. and Iwashita, T. (2007). "Solution structure of agelenin, an intisecticidal peptide isolated from the spider Agelena opulenta, and its structural similarities to insect-specific calcium channel inhibitors". FEBS Letters. 581 (20): 3789–3794. Bibcode:2007FEBSL.581.3789Y. doi:10.1016/j.febslet.2007.06.077. PMID 17644092.
4. Rash, L.D. and Hodgson, W.C. (2002). "Pharmacology and biochemistry of spider venoms". Toxicon. 40 (3): 225–254. Bibcode:2002Txcn...40..225R. doi:10.1016/S0041-0101(01)00199-4. PMID 11711120.