Characterization of Parallel β-Sheets at Interfaces by Chiral Sum Frequency Generation Spectroscopy.
Characterization of protein secondary structures at interfaces is still challenging due to the limitations of surface-selective optical techniques. Here, we address the challenge of characterizing parallel β-sheets by combining chiral sum frequency generation (SFG) spectroscopy and computational modeling. We focus on human islet amyloid polypeptide aggregates and a de novo designed short polypeptide at lipid/water and air/glass interfaces. We find that parallel β-sheets adopt distinct orientations at various interfaces and exhibit characteristic chiroptical responses in the amide I and N-H stretch regions. Theoretical analysis indicates that the characteristic chiroptical responses provide valuable information on the symmetry, orientation, and vibrational couplings of parallel β-sheet at interfaces.
Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.
Li
L
Fu
Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.
Zhuguang
Z
Wang
Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.
Brian T
BT
Psciuk
Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.
Dequan
D
Xiao
Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.
Victor S
VS
Batista
Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.
Elsa C Y
EC
Yan
D000388:Air; D005898:Glass; D006801:Humans; D058228:Islet Amyloid Polypeptide / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D008958:Models, Molecular; D017433:Protein Structure, Secondary; D013057:Spectrum Analysis / Q000379:methods*; D014867:Water / Q000737:chemistry
D058228:Islet Amyloid Polypeptide; D008055:Lipids; D014867:Water
ab initio calculation; amylin; human islet amyloid polypeptide; orientation; vibrational spectroscopy