Difference between revisions of "Part:BBa K5184021"

Latest revision as of 12:17, 2 October 2024

rCtx-4

In order to eliminate spider mites, the spider venom peptide rCtx-4 is incorporated in our project to broaden the spectrum of molecular targets of other venom peptides. rCtx4 is a neurotoxin obtained from the ctenid spider Phoneutria depilata, naturally employed to incapacitate their prey. Having the voltage-gated sodium channels playing a vital role in neuronal, muscular and cardiac functions, targets experience fast immobilization after envenomation, thus it serves as an effective pesticide.

Sequences

Sequence and Features

Assembly Compatibility:

10
COMPATIBLE WITH RFC[10]
12
COMPATIBLE WITH RFC[12]
21
COMPATIBLE WITH RFC[21]
23
COMPATIBLE WITH RFC[23]
25
COMPATIBLE WITH RFC[25]
1000
COMPATIBLE WITH RFC[1000]

Usage and Biology

rCtx-4 is a small cysteine-rich venom peptide derived from Phoneutria depilate, first identified in [1], it consists of 53 amino acids, including 10 Cys residues that form 5 disulfide bonds. It has a cysteine network of C1xxxC2xxxC3xC4C5xxxC6xC7xxxC8xC9xxxC10, with disulfide bridges between C1C5, C2C6, C3C10, C4C9, and C7C8 [Fig1 A&B]. In addition to the covalent disulfide bridges, there is also a pair of beta strands that run antiparallel to each other, allowing hydrogen bonds between each other and, together with the disulfide bonds, folds the protein into a highly compact conformation.

Fig1: (A) Cysteine cross-bridge structure in rCtx4 B. Secondary structure of rCtx4, by structural prediction results from AlphaFold. The cyestine residues are colored orange, displaying their side chains and the rest of the peptide in white

Such a compact conformation gives rise to an inhibitor-cysteine-knot (ICK) structure between C6 and C5, allowing the venom peptide to have inhibitory effects on its molecular target: voltage-gated sodium ion channels, and to have a highly stable structure.

Toxicity Verification

rCtx4 is synthesized using the vector pET28a-G1M5-His-SUMO-rCtx4-GNA-His[Fig2B], of which is assembled using GoldenGate cloning and transformed into E. coli strain DH5ɑ. Colony PCR and sequencing is then carried out to verify the plasmid construct, of which is extracted and transformed into BL21(DE3) strain for expression. After IPTG induction and overnight incubation, the liquid culture is harvested and, after cell lysis, have an SDS-PAGE run. The results suggest that rCtx4 had achieved soluble expression. After several unsuccessful purification attempts, the supernatant is treated directly by SUMO protease [Fig2C].

Fig2: (A) G1M5 tag allows secretion of the fusion protein into extracellular milieu (B) Plasmid construct pET28a-G1M5-His-SUMO-rCtx4-GNA-His (C) SDS-PAGE of supernatant and SUMO-treated supernatant, with supernatant of similarly treated supernatant of BL21(DE3) as control

The SUMO-digested supernatant's toxicity against T. urticae females is tested using a spraying method by Professor Huang from SCAU. Results from the toxicity assay suggests rCtx4 to be highly toxic against T. urticae, achieving an astonishing fatality of 96.49% within 24 hours and complete elimination after another day [Fig2C&D].

Fig3: (A) T. urticae in their normal state, before being sprayed with treated supernatant (B) Dead T. urticae from spraying of treated supernatant (C) Survival plot of T. urticae being sprayed with supernatant containing rCtx4 over 72 hours, CK is similarly processed supernatant of BL21(DE3), acting as a control (D) Lethality data of T. urticae being sprayed with supernatant over 24, 48, and 72 hours, CK is the similarly processed supernatant of BL21(DE3), acting as a control

Part Collection

Our part collection provides a comprehensive list of venom peptides with a diverse range of molecular targets, and all displays satisfactory elimination efficacy during our testings [Fig7A&B].

Fig4: A. Survival plot of 6 venom peptides against female T. urticae using a spraying method, CK is induced liquid culture of BL21(DE3), of which acts as control D. Lethality data of 6 venom peptides over 24, 48, and 72 hours, CK is induced liquid culture of BL21(DE3), of which acts as control; data is the means of ± SD of three parallel replicate experiments

Our Part Collection
Current VP	Venom Name	Targeted Ion Channel	New?	Part Number	Original Specie
	PpVP2S	Ca	New	BBa_K5184043	Phytoseiulus persimilis
	PpVP1S	Ca	New	BBa_K5184042	Phytoseiulus persimilis
	PpVP1F	Ca	New	BBa_K5184038	Phytoseiulus persimilis
✳️	rCtx4	Na		BBa_K5184021	Phoneutria depilata
	Cs1A	Ca		BBa_K5184032	Calommata signata
	HxTx-Hv1h	Ca, K		BBa_K5184033	Hadronyche versuta

References

[1]: Vásquez-Escobar, J.; Benjumea-Gutiérrez, D.M.; Lopera, C.; Clement, H.C.; Bolaños, D.I.; Higuita-Castro, J.L.; Corzo, G.A.; Corrales-Garcia, L.L. Heterologous Expression of an Insecticidal Peptide Obtained from the Transcriptome of the Colombian Spider Phoneutria depilate. Toxins 2023, 15, 436. https://doi.org/10.3390/toxins15070436

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 ==Part Collection==
 Our part collection provides a comprehensive list of venom peptides with a diverse range of molecular targets, and all displays satisfactory elimination efficacy during our testings [Fig7A&B].
-<center><html><img src="https://static.igem.wiki/teams/5184/parts/vp-lethality.webp" width="600"/></html></center>
+<center><html><img src="https://static.igem.wiki/teams/5184/parts/vp-lethality-v.webp" width="600"/></html></center>
 <center><b>Fig4: A. Survival plot of 6 venom peptides against female ''T. urticae'' using a spraying method, CK is induced liquid culture of BL21(DE3), of which acts as control D. Lethality data of 6 venom peptides over 24, 48, and 72 hours, CK is induced liquid culture of BL21(DE3), of which acts as control; data is the means of ± SD of three parallel replicate experiments</b></center>