cycloviolacin O2(21) Protein Card

General Information
Name cycloviolacin O2
Alternative name(s) cO2,CyO2
Class Cyclotide
Technique MS,NGS
Average Mass 3140.69
Monoisotopic Mass 3138.37
m/z M+H 3140.69
ProteinType Wild type
Organism Viola odorata
Hybanthus enneaspermus
Viola baoshanensis
Viola biflora
Viola philippica
Viola uliginosa
Viola arcuata
Viola austrosinensis
Viola anagae
Notes <i>H. enneaspermus</i>: isolated from the plant and fully sequenced by MS/MS (Du et al., 2020).
Cyclic Yes

Motility affected by cyclotides [...]Colgrave ML et al. (2008) Chembiochem 9:1939-1945
A range of natural variants were selected based on net charge and/or hydrophobicity and were tested alongside the prototypic cyclotide kB1 in larval development assays with H. contortus and T. colubriformis. [...]Colgrave ML et al. (2008) Chembiochem 9:1939-1945
Cancer Cell Toxicity
CyO2, CyO13, kalata B1, and varv peptide A exhibited dose-dependent cytotoxicity in MTT assays with IC50 values of 2.15-7.93 uM against human brain astrocytoma cells (U-87 MG) and human bone marrow derived neuroblastoma cells (SH-SY5Y). CyO2 and varv peptide A also sensitized SH-SY5Y and U-87 MG cells to temozolomide (TMZ) which is the only effective chemotherapeutic drug used to treat glioblastoma multiforme (GBM). [...]Gerlach,S.L. et al. (2022) J Nat Prod 85:34-46
Studies using calcein assay and HeLa cells showed that at 10 uM, the increase in calcein leakage is very rapid. [...]Svangard E et al. (2007) J Nat Prod 70:643-647
Psyle A, psyle C, psyle E and cycloviolacin O2 shown to possess cytotoxic activity in cancer cells. [...]Gerlach SL et al. (2010) Biopolymers 94:617-625
Glutamic acid mutant had reduced activity [...]Herrmann A et al. (2006) Cell Mol Life Sci 63:235-45
Cytotoxicity of cyO2, cyO9, hyen D and kB5 and their mutants on HeLa cells. [...]Huang,Y.H. et al. (2021) Molecules 26:0-0
Cycloviolacin O2 showed antitumor effects are minor or absent at tolerable (sublethal) doses, and cycloviolacin O2 has a very abrupt in vivo toxicity profile, with lethality after single injection at 2 mg/kg, but no signs of discomfort to the animals at 1.5 mg/kg. Repeated dosing of 1 mg/kg gave a local-inflammatory reaction at the site of injection after 2–3 days; lower doses were without complications. [...]Burman et al. (2010) Peptide Science 94:626-634
Cell viability and morphology studies on the human lymphoma cell line U-937 GTB showed that cells exposed to cycloviolacin O2 displayed disintegrated cell membranes within 5 min. [...]Svangard E et al. (2007) J Nat Prod 70:643-647
All three cyclotides, varv A, varv F, and cycloviolacin O2, exhibited strong cytotoxic activities, which varied in a dose-dependent manner. [...]Lindholm P et al. (2002) Mol Cancer Ther 1:365-369
Anti-barnacle activity shown for cycloviolacin O2 [...]Goransson U et al. (2004) J Nat Prod 67:1287-90
At a concentration of 25 ºM, a more than 6-fold difference exists between the most hemolyticcyclotide, cycloviolacin O24 (~75% hemolysis), and the least hemolytic cyclotide cycloviolacin O14 (~11% hemolysis). The sensitivity of hemolytic activity to variations in the peptide sequence is evident when comparing cycloviolacin O2 and O13. Here, the only sequence deviation is a single residue substitution of a serine in loop 3 of O2 (HD50 ~36 ºM) to an alanine in the homologous position in O13 (HD50 ~11 ºM). The loss of this single hydroxy group changes the HD50 more than three-fold. [...]Ireland DC et al. (2006) Biochem J. 400:1-12
Cycloviolacin O2 showed antibacterial activity against A. baumannii. [...]Kirkpatrick et al. (2017) Analytical chemistry 89:1194-1201
CyO2,CyO3,CyO13,CyO19 have deterrent activity on M.persicae. [...]Dancewicz,K. et al. (2020) Journal of Insect Physiology 122:104025-0
Membrane Binding Assay
[I11L] mutants of cyO2, cyO9, hyen D and kalata B5 exhibited equipotent binding to the POPC/POPE(80:20) model membrane compared to their wild-type counterparts whereas the [I11G] mutants showed no binding or weak affinity to membranes. [...]Huang,Y.H. et al. (2021) Molecules 26:0-0
Tb3+/DPA Liposome Assay on cycloviolacin O2 showed an effect within minutes [...]Svangard E et al. (2007) J Nat Prod 70:643-647

Goransson U, Sjogren M, Svangard E, Claeson P, Bohlin L (2004) Reversible antifouling effect of the cyclotide cycloviolacin O2 against barnacles. J Nat Prod 67:1287-90
Dutton JL, Renda RF, Waine C, Clark RJ, Daly NL, Jennings CV, Anderson MA, Craik DJ (2004) Conserved structural and sequence elements implicated in the processing of gene-encoded circular proteins. J Biol Chem 279:46858-67
Trabi M, Craik DJ (2004) Tissue-specific expression of head-to-tail cyclized miniproteins in Violaceae and structure determination of the root cyclotide Viola hederacea root cyclotide1. Plant Cell 16:2204-16
Craik DJ, Daly NL, Bond T, Waine C (1999) Plant cyclotides: A unique family of cyclic and knotted proteins that defines the cyclic cystine knot structural motif. J Mol Biol 294:1327-36
Ireland DC, Colgrave ML, Craik DJ (2006) A novel suite of cyclotides from Viola odorata: sequence variation and the implications for structure, function and stability. Biochem J. 400:1-12
Herrmann A, Svangard E, Claeson P, Gullbo J, Bohlin L, Goransson U (2006) Key role of glutamic acid for the cytotoxic activity of the cyclotide cycloviolacin O2. Cell Mol Life Sci 63:235-45
Lindholm P, Goransson U, Johansson S, Claeson P, Gullbo J, Larsson R, Bohlin L, Backlund A (2002) Cyclotides: a novel type of cytotoxic agents. Mol Cancer Ther 1:365-369
Svangard E, Burman R, Gunasekera S, Lovborg H, Gullbo J, Goransson U (2007) Mechanism of action of cytotoxic cyclotides: cycloviolacin O2 disrupts lipid membranes. J Nat Prod 70:643-647
Herrmann A, Burman R, Mylne JS, Karlsson G, Gullbo J, Craik DJ, Clark RJ, Goransson U (2008) The alpine violet, Viola biflora, is a rich source of cyclotides with potent cytotoxicity Phytochemistry 69:939-952
Tang J, Wang CK, Pan X, Yan H, Zeng G, Xu W, He W, Daly NL, Craik DJ, Tan N (2010) Isolation and characterization of cytotoxic cyclotides from Viola tricolor. Peptides 31:1434-1440
Gerlach SL, Rathinakumar R, Chakravarty G, Göransson U, Wimley WC, Darwin SP, Mondal D (2010) Anticancer and chemosensitizing abilities of cycloviolacin O2 from Viola odorata and psyle cyclotides from Psychotria leptothyrsa. Biopolymers 94:617-625
He,W., Chan,L.Y., Zeng,G., Daly,N.L., Craik,D.J. and Tan,N. (2011) Isolation and characterization of cytotoxic cyclotides from Viola philippica. Peptides 32:1719-1723
Burman,R., Strömstedt,A.A., Malmsten,M. and Göransson,U. (2011) Cyclotide-membrane interactions: defining factors of membrane binding, depletion and disruption. Biochim. Biophys. Acta 1808:2665-2673
Slazak,B., Kapusta,M., Strömstedt,A.A., S?omka,A., Krychowiak,M., Shariatgorji,M., Andrén,P.E., Bohdanowicz,J., Kuta,E., and Göransson,U. (2018) How Does the Sweet Violet (Viola odorata L.) Fight Pathogens and Pests - Cyclotides as a Comprehensive Plant Host Defense System Frontiers in plant science 9:0-0
Zhang, J., Li, J., Huang, Z., Yang, B., Zhang, X., Li, D., Craik, D.J., Baker, A.J., Shu, W. and Liao, B. (2015) Transcriptomic screening for cyclotides and other cysteine-rich proteins in the metallophyte Viola baoshanensis. Journal of plant physiology 178:17-26
Slazak, B., Jacobsson, E., Kuta, E. and Göransson, U. (2015) Exogenous plant hormones and cyclotide expression in Viola uliginosa (Violaceae Phytochemistry 117:527-536
Kirkpatrick, C.L., Broberg, C.A., McCool, E.N., Lee, W.J., Chao, A., McConnell, E.W., Pritchard, D.A., Hebert, M., Fleeman, R., Adams, J. and Jamil, A. (2017) The "
Pipeline for Natural Product Bioactive Peptide Discovery Analytical chemistry 89:1194-1201
Burman, R., Svedlund, E., Felth, J., Hassan, S., Herrmann, A., Clark, R.J., Craik, D.J., Bohlin, L., Claeson, P., Göransson, U. and Gullbo, J (2010) Evaluation of toxicity and antitumor activity of cycloviolacin O2 in mice Peptide Science 94:626-634
Dancewicz,K., Slazak,B., Kie?kiewicz,M., Kapusta,M., Bohdanowicz,J., and Gabry?,B. (2020) Behavioral and physiological effects of Viola spp. cyclotides on Myzus persicae (Sulz.) Journal of Insect Physiology 122:104025-0
Du,Q., Chan,L.Y., Gilding,E.K., Henriques,S.T., Condon,N.D., Ravipati,A.S., Kaas,Q., Huang,Y.H. and Craik,D.J. (2020) Discovery and mechanistic studies of cytotoxic cyclotides from the medicinal herb Hybanthus enneaspermus. J Biol Chem 295:10911-10925
Dang,T.T., Chan,L.Y., Huang,Y.H., Nguyen,L.T.T., Kaas,Q., Huynh,T. and Craik,D.J. (2020) Exploring the Sequence Diversity of Cyclotides from Vietnamese Viola Species. J Nat Prod 83:1817-1828
Slazak,B., Kaltenböck,K., Steffen,K., Rogala,M., Rodríguez-Rodríguez,P., Nilsson,A., Shariatgorji,R. and Göransson,U. (2021) Cyclotide host-defense tailored for species and environments in violets from the Canary Islands. Sci Rep 11:12452-0
Huang,Y.H., Du,Q., Jiang,Z., King,G.J., Collins,B.M. and Craik,D.J. (2021) Enabling Efficient Folding and High-Resolution Crystallographic Analysis of Bracelet Cyclotides. Molecules 26:0-0
Gerlach,S.L., Dunlop,R.A., Metcalf,J.S., Banack,S.A., and Cox,P.A. (2022) Cyclotides Chemosensitize Glioblastoma Cells to Temozolomide. J Nat Prod 85:34-46

Protein precursor(s) prcVodo P40 [partial]
Nucleic acids cyclotide c3 precursor
Structure Solution structure of cycloviolacin O2.
Solution structure of the cyclotide cycloviolacin O2
Crystal structure of cycloviolacin O2
Links SwissProt P58434