Melittin

Melittin is the main component (40–60% of the dry weight) and the major pain producing substance of honeybee (Apis mellifera) venom. Melittin is a basic peptide consisting of 26 amino acids.[2]

Melittin
PDB 2mlt EBI.jpg
Melittin
Identifiers
SymbolMelittin
PfamPF01372
InterProIPR002116
SCOP22mlt / SCOPe / SUPFAM
TCDB1.C.18
OPM superfamily151
OPM protein2mlt
Melittin[1]
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.157.496 Edit this at Wikidata
MeSH Melitten
UNII
  • InChI=1S/C131H229N39O31/c1-23-71(16)102(163-97(176)60-135)122(194)146-62-98(177)148-74(19)109(181)164-100(69(12)13)124(196)160-88(55-65(4)5)116(188)155-84(41-30-33-51-134)115(187)165-101(70(14)15)125(197)161-90(57-67(8)9)118(190)168-106(77(22)173)128(200)169-105(76(21)172)123(195)147-63-99(178)150-92(58-68(10)11)129(201)170-54-36-44-94(170)121(193)149-75(20)108(180)158-89(56-66(6)7)117(189)166-104(73(18)25-3)127(199)162-93(64-171)120(192)159-91(59-78-61-145-80-38-27-26-37-79(78)80)119(191)167-103(72(17)24-2)126(198)157-83(40-29-32-50-133)111(183)154-85(42-34-52-143-130(139)140)112(184)152-82(39-28-31-49-132)110(182)153-86(43-35-53-144-131(141)142)113(185)156-87(46-48-96(137)175)114(186)151-81(107(138)179)45-47-95(136)174/h26-27,37-38,61,65-77,81-94,100-106,145,171-173H,23-25,28-36,39-60,62-64,132-135H2,1-22H3,(H2,136,174)(H2,137,175)(H2,138,179)(H,146,194)(H,147,195)(H,148,177)(H,149,193)(H,150,178)(H,151,186)(H,152,184)(H,153,182)(H,154,183)(H,155,188)(H,156,185)(H,157,198)(H,158,180)(H,159,192)(H,160,196)(H,161,197)(H,162,199)(H,163,176)(H,164,181)(H,165,187)(H,166,189)(H,167,191)(H,168,190)(H,169,200)(H4,139,140,143)(H4,141,142,144)/t71-,72-,73-,74-,75-,76+,77+,81-,82-,83-,84-,85-,86-,87-,88-,89-,90-,91-,92-,93-,94-,100-,101-,102-,103-,104-,105-,106-/m0/s1 ☒N
    Key: VDXZNPDIRNWWCW-JFTDCZMZSA-N ☒N
  • InChI=1/C131H229N39O31/c1-23-71(16)102(163-97(176)60-135)122(194)146-62-98(177)148-74(19)109(181)164-100(69(12)13)124(196)160-88(55-65(4)5)116(188)155-84(41-30-33-51-134)115(187)165-101(70(14)15)125(197)161-90(57-67(8)9)118(190)168-106(77(22)173)128(200)169-105(76(21)172)123(195)147-63-99(178)150-92(58-68(10)11)129(201)170-54-36-44-94(170)121(193)149-75(20)108(180)158-89(56-66(6)7)117(189)166-104(73(18)25-3)127(199)162-93(64-171)120(192)159-91(59-78-61-145-80-38-27-26-37-79(78)80)119(191)167-103(72(17)24-2)126(198)157-83(40-29-32-50-133)111(183)154-85(42-34-52-143-130(139)140)112(184)152-82(39-28-31-49-132)110(182)153-86(43-35-53-144-131(141)142)113(185)156-87(46-48-96(137)175)114(186)151-81(107(138)179)45-47-95(136)174/h26-27,37-38,61,65-77,81-94,100-106,145,171-173H,23-25,28-36,39-60,62-64,132-135H2,1-22H3,(H2,136,174)(H2,137,175)(H2,138,179)(H,146,194)(H,147,195)(H,148,177)(H,149,193)(H,150,178)(H,151,186)(H,152,184)(H,153,182)(H,154,183)(H,155,188)(H,156,185)(H,157,198)(H,158,180)(H,159,192)(H,160,196)(H,161,197)(H,162,199)(H,163,176)(H,164,181)(H,165,187)(H,166,189)(H,167,191)(H,168,190)(H,169,200)(H4,139,140,143)(H4,141,142,144)/t71-,72-,73-,74-,75-,76+,77+,81-,82-,83-,84-,85-,86-,87-,88-,89-,90-,91-,92-,93-,94-,100-,101-,102-,103-,104-,105-,106-/m0/s1
    Key: VDXZNPDIRNWWCW-JFTDCZMZBB
  • CCC(C)C(C(=O)NCC(=O)NC(C)C(=O)NC(C(C)C)C(=O)NC(CC(C)C)C(=O)NC(CCCCN)C(=O)NC(C(C)C)C(=O)NC(CC(C)C)C(=O)NC(C(C)O)C(=O)NC(C(C)O)C(=O)NCC(=O)NC(CC(C)C)C(=O)N1CCCC1C(=O)NC(C)C(=O)NC(CC(C)C)C(=O)NC(C(C)CC)C(=O)NC(CO)C(=O)NC(Cc2c[nH]c3c2cccc3)C(=O)NC(C(C)CC)C(=O)NC(CCCCN)C(=O)NC(CCCNC(=N)N)C(=O)NC(CCCCN)C(=O)NC(CCCNC(=N)N)C(=O)NC(CCC(=O)N)C(=O)NC(CCC(=O)N)C(=O)N)NC(=O)CN
Properties
C131H229N39O31
Molar mass 2846.46266
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

FunctionEdit

The principal function of melittin as a component of bee venom is to cause pain and destruction of tissue of intruders that threaten a beehive. However, in honey bees, melittin is not only expressed in the venom gland, but also in other tissues when infected with pathogens. The two venom molecules, melittin and secapin, that are over-expressed in honey bees infected with various pathogens, possibly indicate a role for melittin in the immune response of bees to infectious diseases.[3]

StructureEdit

Melittin is a small peptide with no disulfide bridge; the N-terminal part of the molecule is predominantly hydrophobic and the C-terminal part is hydrophilic and strongly basic. In water, it forms a tetramer but it also can spontaneously integrate itself into cell membranes.[4]

Mechanism of actionEdit

Injection of melittin into animals and humans causes pain sensation. It has strong surface effects on cell membranes causing pore-formation in epithelial cells and the destruction of red blood cells. Melittin also activates nociceptor (pain receptor) cells through a variety of mechanisms.[2]

Melittin can open thermal nociceptor TRPV1 channels via cyclooxygenase metabolites resulting in depolarization of nociceptor cells. The pore forming effects in cells causes the release of pro-inflammatory cytokines. It also activates G-protein-coupled receptor-mediated opening of transient receptor potential channels. Finally melittin up-regulates the expression of Nav1.8 and Nav1.9 sodium channels in nociceptor cell causing long term action potential firing and pain sensation.[2]

Melittin inhibits protein kinase C, Ca2+/calmodulin-dependent protein kinase II, myosin light chain kinase, and Na+/K+-ATPase (synaptosomal membrane). Mellitin blocks transport pumps such as the Na+-K+-ATPase and the H+-K+-ATPase.[2]

Toxicity of a bee stingEdit

Melittin is the main compound in bee venom, accounting for the potential lethality of a bee sting, which causes an anaphylactic reaction in some people.[5] At the sites of multiple stings, localized pain, swelling, and skin redness occur, and if bees are swallowed, life-threatening swelling of the throat and respiratory passages may develop.[5]

UseEdit

Bee venom therapy has been used in traditional medicine for treating various disorders,[6] although its non-specific toxicity has limited scientific research on its potential effects.[7]

ReferencesEdit

  1. ^ Melitten - Compound Summary, PubChem.
  2. ^ a b c d Chen J, Guan SM, Sun W, Fu H (2016). "Melittin, the Major Pain-Producing Substance of Bee Venom". Neuroscience Bulletin. 32 (3): 265–272. doi:10.1007/s12264-016-0024-y. PMC 5563768. PMID 26983715.
  3. ^ Doublet V, Poeschl Y, Gogol-Döring A, Alaux C, Annoscia D, Aurori C, et al. (March 2017). "Unity in defence: honeybee workers exhibit conserved molecular responses to diverse pathogens". BMC Genomics. 18 (1): 207. doi:10.1186/s12864-017-3597-6. PMC 5333379. PMID 28249569.
  4. ^ Terwilliger TC, Eisenberg D (1982). "The structure of melittin. II. Interpretation of the structure" (PDF). The Journal of Biological Chemistry. 257 (11): 6016–6022. PMID 7076662.
  5. ^ a b "Bee venom". Drugs.com. 8 June 2020. Retrieved 11 September 2020.
  6. ^ Rady I, Siddiqui IA, Rady M, Mukhtar H (2017). "Melittin, a major peptide component of bee venom, and its conjugates in cancer therapy". Cancer Letters. 402: 16–31. doi:10.1016/j.canlet.2017.05.010. PMC 5682937. PMID 28536009.
  7. ^ Liu CC, Hao DJ, Zhang Q, An J, Zhao JJ, Chen B, Zhang LL, Yang H (2016). "Application of bee venom and its main constituent melittin for cancer treatment". Cancer Chemotherapy and Pharmacology. 78 (6): 1113–1130. doi:10.1007/s00280-016-3160-1. PMID 27677623. S2CID 12596298.

External linksEdit