Session J39: Physics of Proteins III: Folding, Structure and Stability

11:15 AM–2:15 PM, Tuesday, March 22, 2011
Room: A124/127

Sponsoring Unit: DBP
Chair: Bernard Gerstman, Florida International University

Abstract ID: BAPS.2011.MAR.J39.1

Abstract: J39.00001 : The Speed Limit of Protein Folding: Alpha-Helix Initiation Modeled and Observed

11:15 AM–11:27 AM

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Authors:

  Milo Lin
    (Physical Biology Center for Ultrafast Science and Technology, California Institute of Technology)

  Omar Mohammed
    (Physical Biology Center for Ultrafast Science and Technology, California Institute of Technology)

  Ahmed Zewail
    (Physical Biology Center for Ultrafast Science and Technology, California Institute of Technology)

As a primary event of protein folding, alpha-helix initiation is the starting point of macromolecular complexity. In this work, an analytic coarse-grained model which predicts the initiation rate as a function of temperature, is presented. Helix initiation was measured via ultrafast temperature-jump fluorescence refolding experiments on two penta-peptides, and the measured rates agreed well with those of the model. In addition, the temporal separation of rate-limiting diffusion from fast annealing stipulated by the model was confirmed via ensemble-converging all-atom molecular dynamics simulations, which reproduced both the diffusion and the picosecond annealing processes and rates observed experimentally. Some of these results were published in: Mohammed OF, Jas GS, Lin MM, Ma H, Zewail AH (2009) Primary peptide folding dynamics observed with ultrafast temperature jump. Angew Chem 48: 5628-5632.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.J39.1