Cupricyclins, novel redox-active metallopeptides based on conotoxins scaffold.
Highly stable natural scaffolds which tolerate multiple amino acid substitutions represent the ideal starting point for the application of rational redesign strategies to develop new catalysts of potential biomedical and biotechnological interest. The knottins family of disulphide-constrained peptides display the desired characteristics, being highly stable and characterized by hypervariability of the inter-cysteine loops. The potential of knottins as scaffolds for the design of novel copper-based biocatalysts has been tested by engineering a metal binding site on two different variants of an ω-conotoxin, a neurotoxic peptide belonging to the knottins family. The binding site has been designed by computational modelling and the redesigned peptides have been synthesized and characterized by optical, fluorescence, electron spin resonance and nuclear magnetic resonance spectroscopy. The novel peptides, named Cupricyclin-1 and -2, bind one Cu(2+) ion per molecule with nanomolar affinity. Cupricyclins display redox activity and catalyze the dismutation of superoxide anions with an activity comparable to that of non-peptidic superoxide dismutase mimics. We thus propose knottins as a novel scaffold for the design of catalytically-active mini metalloproteins.
Department of Biology, University Roma Tre, Rome, Italy.
Marco
M
Barba
Anatoli P
AP
Sobolev
Veranika
V
Zobnina
Maria Carmela
MC
Bonaccorsi di Patti
Laura
L
Cervoni
Maria Carolina
MC
Spiezia
M Eugenia
ME
Schininà
Donatella
D
Pietraforte
Luisa
L
Mannina
Giovanni
G
Musci
Fabio
F
Polticelli
D001665:Binding Sites; D002121:Calcium Channel Blockers; D020916:Conotoxins / Q000737:chemistry*; D003300:Copper / Q000378:metabolism; D015195:Drug Design; D008667:Metalloproteins / Q000138:chemical synthesis / Q000737:chemistry* / Q000235:genetics; D009498:Neurotoxins; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry*; D015202:Protein Engineering
D002121:Calcium Channel Blockers; D020916:Conotoxins; D008667:Metalloproteins; D009498:Neurotoxins; D010455:Peptides; D003300:Copper