Article

Vibrational energy transport through a capping layer of appropriately designed peptide helices over gold nanoparticles.

Physikalisch-Chemisches Institut, Universität Zürich, CH-8057 Zürich, Switzerland.
Nano Letters (Impact Factor: 13.03). 08/2010; 10(8):3057-61. DOI: 10.1021/nl101580w
Source: PubMed

ABSTRACT We design and characterize spherical gold nanoparticles, which are covalently linked to and completely covered by 3(10)-helical peptides. These helices provide a scaffold to place (13)C=O isotope labels at defined distances from the gold surface, which we employ as local thermometers. Probing these reporter groups with transient infrared spectroscopy, we monitor the vibrational energy flow across the peptide capping layer following excitation of the nanoparticle plasmon resonance.

0 Bookmarks
 · 
81 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Fascinating anisotropy decay experiments have recently been performed on H2O ice Ih by Timmer and Bakker [R. L. A. Timmer, and H. J. Bakker, J. Phys. Chem. A 114, 4148 (2010)]. The very fast decay (on the order of 100 fs) is indicative of resonant energy transfer between OH stretches on different molecules. Isotope dilution experiments with deuterium show a dramatic dependence on the hydrogen mole fraction, which confirms the energy transfer picture. Timmer and Bakker have interpreted the experiments with a Förster incoherent hopping model, finding that energy transfer within the first solvation shell dominates the relaxation process. We have developed a microscopic theory of vibrational spectroscopy of water and ice, and herein we use this theory to calculate the anisotropy decay in ice as a function of hydrogen mole fraction. We obtain very good agreement with experiment. Interpretation of our results shows that four nearest-neighbor acceptors dominate the energy transfer, and that while the incoherent hopping picture is qualitatively correct, vibrational energy transport is partially coherent on the relevant timescale.
    The Journal of Chemical Physics 06/2014; 140(24):244503. · 3.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In a previous paper [M. Schade, P. Hamm, Vibrational energy transport in the presence of intrasite vibrational energy redistribution, J. Chem. Phys. 131 (2009) 044511], it has been shown that on ultrashort length and time scales, the speed of vibrational energy transport along a molecular chain is limited by intrasite vibrational relaxation rather than the actual intersite propagation. However, since intrasite vibrational relaxation is length independent, the intersite propagation rate is expected to become rate-limiting at some length scale, where propagation approaches the bulk limit. In the present paper, we investigate the transition between both regimes. The response of different types of modes may be very different at early times, depending on how much they contribute directly to energy transport. Surprisingly though, when averaging the energy content over all vibrational modes of the various chain sites, the complexity of the intrasite vibrational relaxation process is completely hidden so that energy transport on the nanoscale can be described by an effective propagation rate, that equals the bulk value, even at short times.
    Chemical Physics 01/2012; 393(1):46–50. · 1.96 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Allosteric interactions in proteins generally involve propagation of local structural changes through the protein to a remote site. Anisotropic energy transport is thought to couple the remote sites, but the nature of this process is poorly understood. Here, we report the relationship between energy flow through the structure of bovine serum albumin and allosteric interactions between remote ligand binding sites of the protein. Ultrafast infrared spectroscopy is used to probe the flow of energy through the protein backbone following excitation of a heater dye, a metalloporphyrin or malachite green, bound to different binding sites in the protein. We observe ballistic and anisotropic energy flow through the protein structure following input of thermal energy into the flexible ligand binding sites, without local heating of the rigid helix bundles that connect these sites. This efficient energy transport mechanism enables the allosteric propagation of binding energy through the connecting helix structures.
    Nature Communications 01/2014; 5:3100. · 10.74 Impact Factor