Structural Transitions as Determinants of the Action of the Calcium-Dependent Antibiotic Daptomycin.
Jung, D., Rozek, A., Okon, M., Hancock, R.E.(2004) Chem Biol 11: 949
- PubMed: 15271353 
- DOI: https://doi.org/10.1016/j.chembiol.2004.04.020
- Primary Citation of Related Structures:  
1T5M, 1T5N - PubMed Abstract: 
Daptomycin is a cyclic anionic lipopeptide antibiotic recently approved for the treatment of complicated skin infections (Cubicin). Its function is dependent on calcium (as Ca2+). Circular dichroism spectroscopy indicated that daptomycin experienced two structural transitions: a transition upon interaction of daptomycin with Ca2+, and a further transition upon interaction with Ca2+ and the bacterial acidic phospholipid, phosphatidyl glycerol. The Ca2+-dependent insertion of daptomycin into model membranes promoted mild and more pronounced perturbations as assessed by the increase of lipid flip-flop and membrane leakage, respectively. The NMR structure of daptomycin indicated that Ca2+ induced a conformational change in daptomycin that increased its amphipathicity. These results are consistent with the hypothesis that the association of Ca2+ with daptomycin permits it to interact with bacterial membranes with effects that are similar to those of the cationic antimicrobial peptides.
Organizational Affiliation: 
Department of Microbiology and Immunology, University of British Columbia, 232B-2259 Lower Mall, Vancouver, BC, V6T 1Z4, Canada.