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CD and NMR structural characterization of ceratotoxins, natural peptides with antimicrobial activity
Author(s) -
Ragona Laura,
Molinari Henriette,
Zetta Lucia,
Longhi Renato,
Marchini Daniela,
Dallai Romano,
Bernini Luigi F.,
Lozzi Luisa,
Scarselli Maria,
Niccolai Neri
Publication year - 1996
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/(sici)1097-0282(199611)39:5<653::aid-bip4>3.0.co;2-v
Subject(s) - ramachandran plot , chemistry , melittin , peptide , stereochemistry , peptide fragment , antimicrobial peptides , structural motif , antimicrobial , crystallography , biochemistry , protein structure , organic chemistry
Antibacterial properties of the secretion from the female reproductive accessory glands of medfly Ceratitis capitata are mostly ascribed to the presence of two peptides, ceratotoxin A and B, which exhibit a strong activity against gram‐positive and gram‐negative bacterial strains, and show sequence and function homology with cecropins, melittin, and magainins. CD experiments performed in different solvents indicate the presence of a significant content of helical structures in organic solvent. Two‐dimensional nmr results for ceratotoxin A in methanol show a helical behavior for the 8–25 region of the peptide. A Ramachandran classification of each residue for the structures obtained from distance geometry calculations lead to the definition of four structural families in which the central segment 10–19 is always helical and differences refer to residues 8–9 and 19–23. A sequence analysis of the two ceratotoxins and a systematic search on the protein data bank revealed the occurrence of a KX‐hydrophobic‐hydrophobic‐P motif that seems to be important for helix stabilization. © 1996 John Wiley & Sons, Inc.