Effect of the surface on the secondary structure of soft landed peptide ions
Ion soft landing (SL) enables highly selective modification of substrates for applications in materials science, nanotechnology and biology. Our previous study showed that SL can be used for preparation of conformation-selected peptide arrays. Here we present a first study of the effect of the surface on the secondary structures of peptides soft-landed onto self-assembled monolayer surfaces (SAMs). Conformations of soft-landed peptide ions were examined using the newly constructed instrument that enables in situ infrared reflection absorption spectroscopy (IRRAS) characterization of surfaces during and after ion deposition. Polyalanine peptides, Ac-AnK and Ac-KAn (n=7, 15), that have been extensively studied both in solution and in the gas phase were used as model systems in this study. We demonstrate that physical and chemical properties of SAM surfaces have a strong effect on the conformations of soft-landed peptides ions. For example, deposition of the α-helical [Ac-A15K+H]+ ion on the CH3-terminated (HSAM) surface results in immobilization of both the α- and 310-helical conformations. In contrast, a significant fraction of Ac-A15K molecules are present in the β-sheet conformation on the CF3- (FSAM) and COOH-terminated (COOH-SAM) surfaces. We show that the kinetic energy of the polyalanine ion, the charge, and the initial conformation have only a minor effect on the conformation of deposited species suggesting that the interaction between the molecule and the surface plays a major role in determining the secondary structures of immobilized polyalanines. This study demonstrates that SL of mass-selected ions can be utilized for obtaining fundamental understanding of the intrinsic properties of biomolecules and surfaces responsible for conformational changes upon adsorption.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 990530
- Report Number(s):
- PNNL-SA-73321; 19594; 34913; KC0302020; TRN: US201020%%390
- Journal Information:
- Physical Chemistry Chemical Physics. PCCP, 12(39):12802-12810, Vol. 12, Issue 39
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
ADSORPTION
BIOLOGY
CHEMICAL PROPERTIES
CONFORMATIONAL CHANGES
DEPOSITION
KINETIC ENERGY
MODIFICATIONS
PEPTIDES
REFLECTION
SUBSTRATES
ion soft-landing
α-helix
β-sheet
peptide immobilization
self-assembled monolayer
conformational change
infrared spectroscopy
Environmental Molecular Sciences Laboratory