cycloviolacin O13(170) Protein Card

General Information
Name cycloviolacin O13
Sequence GIPCGESCVWIPCISAAIGCSCKSKVCYRN
Class Cyclotide
Average Mass 3124.69
Monoisotopic Mass 3122.37
m/z M+H 3123.38
ProteinType Wild type
Parent
Organism Viola odorata
Notes
Cyclic Yes

Assay
Enzymatic Digest
Cycloviolacin O13, O14, O16 and O24 were tested for their stability against proteolytic degradation by pepsin, trypsin and thermolysin.No degradation by proteases was observed for any of the cyclotides tested following 6 hours of incubation with enzymes, while the linear control peptide was completely degraded in less than 5 minutes. [...]Ireland DC et al. (2006) Biochem J. 400:1-12
Anti-HIV
Cycloviolacin O13, O14 and O24 inhibited the cytopathic effects of HIV-1 infection in cultured human T-lymphoblast (CEM-SS) cells with antiviral cytoprotective concentrations (EC50) of 320, 440, and 308 nM, while the cytotoxic concentration (IC50) was 6.4, 4.8, and 6.2 uM, respectively [...]Ireland DC et al. (2008) Biopolymers 90:51-60
Hemolytic
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
Nematocidal
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

References
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
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

Cross-references
Protein precursor(s) cyclotide c3 precursor
Nucleic acids cyclotide c3 precursor
Structure
Links GenBank Q5USN8.1
SwissProt Q5USN8

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