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Multiple Disulfide Bridge Peptides

Cysteine (Cys) residues in proteins and peptides are capable of forming disulfide bonds (i.e., disulfide bridges), a reversible covalent linkage between two side chain thiol groups. Disulfide bonds confer conformational constraints in linear peptide sequences that molecular rigidity and more stable secondary structures. Disulfide rich peptides are less prone to enzymatic degradation and can sometimes increase binding affinity to the corresponding receptor.

Conformationally stable disulfide-rich peptides has lead to many selective and potent classes of peptides. Toxin peptides from scorpions (e.g., chlorotoxin), cone snails (e.g., conotoxins), snakes, and spiders as well as host-defense peptides (e.g., α-defensins and β-defensins are important classes with diverse pharmacological applications. Conotoxins and chlorotoxins are potent blockers of ion channels and have been indicated as treatments for chronic pain and cancer. Chlorotox and defensin peptide sequences

Host defense peptides like α- and β-defensins have indications in cancer and antimicrobial therapeutics. Defensins contain stable β-sheet and α-helix secondary structures which are important for their pore-forming modes of action on the cellular membranes of bacteria. To learn more about antimicrobial peptides (AMPs) please read our AMP mini-review. Learn More »

defensin peptides

Molecular models of β-Defensin 1 (left) and α-defensin-6 (right) show three disulfide bonds stabilizing both β-sheet and α-helical structures.

Custom Peptide Synthesis multiple disulfide bridges

Chlorotoxin (CLTX-001) Learn More »
(H-Met-Cys-Met-Pro-Cys-Phe-Thr-Thr-Asp-His-Gln-Met-Ala-Arg-Lys-Cys-Asp-Asp-Cys-Cys-Gly-Gly-Lys-Gly-Arg-Gly-Lys-Cys-Tyr-Gly-Pro-Gln-Cys-Leu-Cys-Arg-NH2 (Disulfide Bridges: Cys1-Cys4, Cys2-Cys6, Cys3-Cys7, Cys5-Cys8)

Multiple Disulfide Bridged Peptide Citations

"Cryptdin 2 (UniProtKB: P28309, LRDLVCYCRTRGCKRRERMNGTCRKGHLMYTLCCR)... obtained by oxidative refolding of partially purified linear peptides (synthesized by CPC Scientific...) and purifying the correctly folded species by reverse-phase high-pressure liquid chromatography (RP-HPLC). Purity was determined by analytical RP-HPLC, and the mass of the disulfide-bonded peptides was verified by high mass accuracy liquid chromatography-mass spectrometry. "

1. Wilson, Sarah S., et al. "Alpha-defensin-dependent enhancement of enteric viral infection." PLoS Pathogens 13.6 (2017): e1006446.Learn More »

"(R/K)-RMAD-4 [(R1/2/5/7/10/13/14/26/33K)-RMAD-462-94] was custom synthesized by CPC Scientific, Inc. (San Jose, CA) and refolded as described previously"

2. Llenado, R. Alan, et al. "Electropositive charge in α-defensin bactericidal activity: functional effects of Lys-for-Arg substitutions vary with the peptide primary structure." Infection and Immunity 77.11 (2009): 5035-5043.Learn More »

"(R/K)-RMAD4 (supplemental Fig. S1) was synthesized in solid phase and purchased from CPC Scientific, Inc. (Sunnyvale, CA)."

3. Schmidt, Nathan W., et al. "Arginine in α-defensins differential effects on bactericidal activity correspond to geometry of membrane curvature generation and peptide-lipid phase behavior." Journal of Biological Chemistry 287.26 (2012): 21866-21872.Learn More »

"Folded HD5 was made from a synthesized 80% pure linearized peptide (CPC Scientific, Sunnyvale, CA) and purified by reverse-phase high-pressure liquid chromatography, and an HD5 derivative containing L-α-aminobutyric acid in place of cysteine (HD5 Abu) was chemically synthesized, as previously described"

4. Wiens, Mayim E., and Jason G. Smith. "Alpha-defensin HD5 inhibits furin cleavage of human papillomavirus 16 L2 to block infection." Journal of Virology 89.5 (2015): 2866-2874.Learn More »

"Folded Crp23 was created from a synthesized 80% pure linear peptide (CPC Scientific, Sunnyvale, CA) by the same procedure as previously reported for the α-defensin HD5"

5. Wilson, Sarah S., et al. "A small intestinal organoid model of non-invasive enteric pathogen–epithelial cell interactions." Mucosal Immunology 8.2 (2015): 352-361.Learn More »

"..folded HD5 was generated from a synthesized 80% pure linear peptide (CPC Scientific, Sunnyvale, CA) by thiol disulfide reshuffling overnight at room temperature in the presence of 3 mM reduced and 0.3 mM oxidized glutathione, 2 M guanidine hydrochloride, and 0.25 M sodium bicarbonate, pH 8.3, at a peptide concentration of 0.25 mg/ml, purified to homogeneity by reverse-phase high pressure liquid chromatography, and lyophilized as described previously (17). The synthesis, refolding, purification, and structural validation of the HD5 analogs have been described for R9A, R13A, R25A, R28A, R32A, E21me, and Leu-29 substitutions (12) and R9A/R28A, R9K/R28K, R13A/R32A, and R13K/R32K (9). All α-defensins were quantified by UV absorbance at 280 nm using calculated molar extinction coefficients (18)."

6. Gounder, Anshu P., et al. "Critical determinants of human α-defensin 5 activity against non-enveloped viruses." Journal of Biological Chemistry 287.29 (2012): 24554-24562.Learn More »