title: Interfacial orientation and secondary structure change in tachyplesin I: molecular dynamics and sum frequency generation spectroscopy studies.
abstract: Recent advances in the collection and interpretation of surface-sensitive vibrational spectroscopic measurements have made it possible to study the orientation of peptides and proteins in situ in a biologically relevant environment. However, interpretation of sum frequency generation (SFG) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) vibrational spectroscopy is hindered by the fact that orientation cannot be inferred without some prior knowledge of the protein structure. In this work, molecular dynamics simulations were used to study the interfacial orientation and structural deformation of the short β-sheet peptide tachyplesin I at the polystyrene/water interface. By combining these results with ATR-FTIR and SFG measurements, reasonable agreement was found with the simulation results, suggesting that tachyplesin I lies parallel to the surface, although the simulation results imply a broader distribution of peptide twist angles than could be characterized using available experimental measurements. The interfacial structure was found to be deformable even when disulfide bonds were preserved, and these local deviations from a purely extended β-sheet conformation may be of importance to future developments in the interpretation of SFG and ATR-FTIR spectra.
authors: Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, USA.
authors: Andrew P
authors: AP
authors: Boughton
authors: Khoi
authors: K
authors: Nguyen
authors: Ioan
authors: I
authors: Andricioaei
authors: Zhan
authors: Z
authors: Chen
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D010456:Peptides, Cyclic / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013055:Spectrophotometry, Infrared
chemical_list: D023181:Antimicrobial Cationic Peptides; D004268:DNA-Binding Proteins; D010456:Peptides, Cyclic; C057636:tachyplesin peptide, Tachypleus tridentatus