Conformational analysis of the broad-spectrum antibacterial peptide, ranatuerin-2CSa: Identification of a full length helix-turn-helix motif.Subasinghage, A.P., Conlon, J.M., Hewage, C.M.
(2008) Biochim.Biophys.Acta 1784: 924-929
- PubMed: 18387372
- DOI: 10.1016/j.bbapap.2008.02.019
- PubMed Abstract:
Design of clinically valuable antibacterial agents based upon naturally occurring peptides requires the use of spectroscopic methods, particularly NMR, to determine the three-dimensional structure of the native peptide so that analogues with improved ...
Design of clinically valuable antibacterial agents based upon naturally occurring peptides requires the use of spectroscopic methods, particularly NMR, to determine the three-dimensional structure of the native peptide so that analogues with improved therapeutic properties can be made. Ranatuerin-2CSa (GILSSFKGVAKGVAKDLAG KLLETLKCKITGC), first isolated from skin secretions of the Cascades frog, Rana cascadae, represents a promising candidate for drug development. The peptide shows potent growth inhibitory activity against Escherichia coli (MIC=5 microM) and Staphylococcus aureus (MIC=10 microM) but displays haemolytic activity against human erythrocytes (LC(50)=160 microM). The solution structure of ranatuerin-2CSa was investigated by proton NMR spectroscopy and molecular modelling. In aqueous solution, the peptide lacks secondary structure but, in a 2,2,2-trifluoroethanol (TFE-d(3))-H(2)O solvent mixture, the structure is characterised by a full length helix-turn-helix conformation between residues I(2)-L(21), L(22)-L(25) and K(26)-T(30) respectively. This structural information will facilitate the design of novel therapeutic agents based upon the ranatuerin-2CSa structure with improved antimicrobial potencies but decreased cytolytic activities against mammalian cells.
UCD School of Biomolecular and Biomedical Science, UCD Centre for Synthesis and Chemical Biology, UCD Conway institute, University College Dublin, Belfield, Dublin 4, Ireland.