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06:26
Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Disorder influence on linear dichroism analyses of smectic phases
Joshua Manor1, Ziad Khattari, Tim Salditt
1Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
Biophysical Journal
|April 19, 2005
Summary
Linear dichroism (LD) measures polymer orientation and disorder. This study quantizes disorder effects on LD, finding minimal impact below 10 degrees, crucial for structural studies.
Area of Science:
- Biophysics
- Polymer Science
- Structural Biology
Background:
- Linear dichroism (LD) quantifies anisotropic ordering in materials like polymers and lipid bilayers.
- LD measures both chromophore transition dipole moment (TDM) orientation and sample disorder.
- Accurate TDM orientation is vital for high-resolution structural studies.
Purpose of the Study:
- To rigorously analyze the impact of sample disorder on linear dichroism measurements.
- To develop a method for estimating disorder effects on calculated TDM orientation.
- To validate the Gaussian disorder model in conjunction with LD data.
Main Methods:
- Implementation of the Gaussian disorder model with linear dichroism data.
- Calculation of rod tilt and rotational pitch angles as a function of disorder.
- Application of the developed theory to the HIV Vpu transmembrane domain.
Main Results:
- Disorders below 5 degrees have negligible effects on calculated polymer orientation.
- Disorders below 10 degrees have negligible effects on calculated orientational parameters.
- Disorders exceeding 10 degrees significantly impact orientational parameters, necessitating estimation.
Conclusions:
- The Gaussian disorder model effectively quantifies disorder effects in LD analysis.
- Accurate structural characterization using LD requires estimating disorder above 10 degrees.
- The method was successfully applied to the HIV Vpu transmembrane domain using experimental data.
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