ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The effects of interaction with phospholipids on the conformation of the alternating copolymer, poly(Leu-Lys), and the random copolymer poly(Leu50, Lys50) have been investigated by CD and ir spectroscopy. Poly(Leu-Lys) undergoes a partial unordered → β-sheet transition in solution in the presence of lysolecithin. On addition of lysolecithin plus cholate, an unordered → α -helix transition is observed. In films deposited from these solutions, poly(Leu-Lys) adopts the anti-parallel β-sheet conformation, as in aqueous solutions at moderate ionic strength. Polarized ir spectra showed that the plane of the β-sheet in such films deviates from the plane of the film by no more than 14°. The random copolymer, poly(Leu50, Lys50), is α-helical in the presence of lysolecithin and lysolecithin plus cholate, regardless of whether the sample is a solution or a film. CD measurements on the poly(Leu-Lys) films provide information about the component of the CD tensor for light propagating normal to the plane of the β-sheet. These measurements show (1) a negative n → π* CD band (214 nm maximum) with higher intensity than the average CD for isotropic solution; and (2) a positive band in the π → π* region (195 nm maximum), which is weaker than that in the isotropic spectrum.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360260710
