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Interfacial Molecular-level Structures of Polymers and Biomacromolecules Revealed via Sum Frequency Generation Vibrational Spectroscopy
Published on: August 13, 2019
Orientation determination of interfacial beta-sheet structures in situ
Khoi Tan Nguyen1, John Thomas King, Zhan Chen
1Department of Chemistry, 930 North University Avenue, University of Michigan, Ann Arbor, Michigan 48109, USA.
The Journal of Physical Chemistry. B
|May 28, 2010
Summary
This study introduces a novel method to quantify interfacial beta-sheet orientation using combined spectroscopy. This technique determines both tilt and twist angles for peptides at interfaces, advancing structural biology.
Area of Science:
- Biophysics
- Biochemistry
- Structural Biology
Background:
- Understanding interfacial protein and peptide structure is vital for applications like biosensing and biocompatibility.
- Alpha-helical and beta-sheet structures are common secondary protein structures.
- Quantifying the orientation of these structures at interfaces is challenging.
Purpose of the Study:
- To develop a method for quantifying the orientation of interfacial beta-sheet structures.
- To determine both tilt and twist angles of beta-sheets at interfaces.
- To illustrate the methodology using a specific peptide and surfaces.
Main Methods:
- Combined attenuated total reflectance Fourier transformation infrared spectroscopy (ATR-FTIR) and sum frequency generation (SFG) vibrational spectroscopy.
- Utilized polarized ATR-FTIR amide I signals and regular/chiral SFG spectra.
- Applied to tachyplesin I peptide adsorbed to polymer surfaces and lipid bilayers.
Main Results:
- Successfully quantified the orientation of interfacial beta-sheet structures.
- Determined the tilt angle (theta) and twist angle (psi) of the beta-sheet.
- Demonstrated the method's applicability to complex molecular systems.
Conclusions:
- A new spectroscopic method enables in situ determination of interfacial beta-sheet orientation.
- This method provides detailed structural information (tilt and twist angles).
- Integration with existing alpha-helix methods expands optical spectroscopy applications in various scientific fields.
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