Conformation of gramicidin-A in CTAB micellar media

J Photochem Photobiol B. May-Jun 2003;70(2):117-24. doi: 10.1016/s1011-1344(03)00055-1.

Abstract

Gramicidin A (gA) is a linear pentadecapeptide, which exhibits various conformations depending on the environment. The conformational behavior of gA in spherical and rod-shaped cationic micelles formed by cetyltrimethylammonium bromide (CTAB) surfactant has been studied using circular dichroism (CD) and fluorescence spectroscopy, and a probable structure of gramicidin A in CTAB media has been proposed. A CD study shows that gramicidin A assumes beta(6.3) helical structure in cationic spherical as well as rod-shaped CTAB micellar media. Modeling studies show the flexibility of the side chain conformation particularly in tryptophan-9. Study of intrinsic fluorescence of tryptophans in gramicidin A indicates three distinct environments for the four-tryptophan residues in CTAB media.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cetrimonium
  • Cetrimonium Compounds / chemistry*
  • Circular Dichroism
  • Gramicidin / chemistry*
  • Micelles
  • Models, Molecular
  • Protein Conformation
  • Spectrometry, Fluorescence

Substances

  • Cetrimonium Compounds
  • Micelles
  • Gramicidin
  • Cetrimonium