CD and NMR structural characterization of ceratotoxins, natural peptides with antimicrobial activity.
Related Articles CD and NMR structural characterization of ceratotoxins, natural peptides with antimicrobial activity.
Biopolymers. 1996 Nov;39(5):653-64
Authors: Ragona L, Molinari H, Zetta L, Longhi R, Marchini D, Dallai R, Bernini LF, Lozzi L, Scarselli M, Niccolai N
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.
PMID: 8875820 [PubMed - indexed for MEDLINE]
Source:
PubMed