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Diffuse scattering provides material parameters and electron density profiles of biomembranes

Yufeng Liu and John F. Nagle

  • Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA

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Phys. Rev. E 69, 040901(R) – Published 30 April, 2004

DOI: https://doi.org/10.1103/PhysRevE.69.040901

Abstract

Fully hydrated stacks of DOPC lipid bilayer membranes generate large diffuse x-ray scattering that corrupts the Bragg peak intensities that are used in conventional biophysical structural analysis, but the diffuse scattering actually contains more information. Using an efficient algorithm for fitting extensive regions of diffuse data to classical smectic liquid crystalline theory we first obtain the compressional modulus B=1013erg∕cm4, which involves interactions between membranes, and the bending modulus Kc=8×10−13erg of the membranes. The membrane form factor F(qz) is then obtained for most values of qz up to 0.8Å−1. The electron density profile ρ(z) is obtained by fitting models to F(qz). Constraining the models to conform to other measurements provides structural quantities such as area A=72.1±0.5Å2 per lipid at the interface.

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Phys. Rev. E 69, 040901(R)– Published 30 April, 2004
  • Received 3 September 2003

© 2004 American Physical Society

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