Temperature dependence of the interaction of alamethicin helices in membranes.
The interaction of the voltage-dependent channel-forming peptide alamethicin with dioleoylphosphatidylcholine (DOPC) small unilamellar vesicles (SUV) has been studied using circular dichroism spectroscopy over a range of wavelengths and temperatures. Evidence is presented for the existence of two distinct membrane-bound states of the peptide which reflect different extents of peptide-peptide interaction. An elevated temperature is found to diminish the apparent peptide-peptide interaction. These results provide insight into the general problem of helix-helix interaction in membranes and provide experimental support for the proposal [Popot, J. L., & Engelman, D. M. (1990) Biochemistry 29, 4031-4037] that these interactions can be enthalpically favorable.
Woolley
G A
GA
Department of Crystallography, Birkbeck College, University of London, U.K.
Wallace
B A
BA
D000408:Alamethicin / Q000737:chemistry*; D002942:Circular Dichroism; D007473:Ion Channels / Q000737:chemistry*; D008567:Membranes, Artificial; D010713:Phosphatidylcholines / Q000737:chemistry*; D011485:Protein Binding; D013696:Temperature
D007473:Ion Channels; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D000408:Alamethicin; C017251:1,2-oleoylphosphatidylcholine