Fourier transform infrared spectroscopy is used to study the molecular interaction between gramicidin D and bilayer membranes, dioctadecadimethylammonium bromide (2C18N+2C1Br-), and 1,2-di-palmytoyl-l-α-phosphatidylcholine (DPPC). Frequencies and bandwidths of the symmetric CH2 stretching band measured as a function of temperature are used to study variation of packing of alkyl chains. The bilayer membrane prepared from 2C18N+2C1Br- is found to have a gel to liquid crystal phase transition at 42°C. The presence of gramicidin in the membrane causes an increase in the mobility of the alkyl chain and also a decrease in the abruptness of the transition. The frequencies of amide I and II bands of gramicidin reflecting secondary structures of polypeptides are used to identify its conformation in membranes and to study the interaction between gramicidin and the matrices. Gramicidin is found to have hydrophobic interaction with 2C18N+2C1Br-, whereas it has both hydrophobic and hydrophilic interactions with DPPC.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Colloid and Surface Chemistry