NMR solution structure of viscotoxin C1 from Viscum album species Coloratum ohwi: toward a structure-function analysis of viscotoxins.
The high resolution three-dimensional structure of the newly discovered plant viscotoxin C1, from the Asiatic Viscum album ssp. Coloratum ohwi, has been determined in solution by (1)H NMR spectroscopy at pH 3.6 and 285 K. The viscotoxin C1-fold, consisting of a helix-turn-helix motif and a short stretch of an antiparralel beta-sheet is very similar to that found for the highly similar viscotoxins A2 and A3 and for other related thionins. Different functional properties of members of the thionin family are discussed here in light of the structural and electrostatic properties. Among the very homologous family of alpha- and beta-thionins, known for their antimicrobial activity, the viscotoxin subfamily differs from the other members because of its high toxicity against tumoral cells. Key residues for the modulation of viscotoxin cytotoxicity have been identified on the basis of sequence and structural alignment.
Dipartimento Scientifico e Tecnologico, Università degli Studi di Verona, Strada le Grazie 15, 37134 Verona, Italy.
Silvia
S
Romagnoli
Federico
F
Fogolari
Maddalena
M
Catalano
Lucia
L
Zetta
Gerhard
G
Schaller
Konrad
K
Urech
Matteo
M
Giannattasio
Laura
L
Ragona
Henriette
H
Molinari
D000595:Amino Acid Sequence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D028321:Plant Preparations / Q000737:chemistry* / Q000494:pharmacology*; D010940:Plant Proteins; D011487:Protein Conformation; D054790:Ribosome Inactivating Proteins, Type 2; D055672:Static Electricity; D013329:Structure-Activity Relationship; D014118:Toxins, Biological / Q000737:chemistry* / Q000494:pharmacology*; D028182:Viscum album / Q000737:chemistry*
D028321:Plant Preparations; D010940:Plant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C009674:ribosome inactivating protein, Viscum; C488038:viscotoxin