Observing Vibrational Energy Flow in a Protein with the Spatial Resolution of a Single Amino Acid Residue
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- 作者：Naoki Fujii ; Misao Mizuno ; Haruto Ishikawa ; Yasuhisa Mizutani
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2014
- 出版时间：September 18, 2014
- 年：2014
- 卷：5
- 期：18
- 页码：3269-3273
- 全文大小：262K
- ISSN：1948-7185
文摘
One of the challenges in physical chemistry has been understanding how energy flows in a condensed phase from the microscopic viewpoint. To address this, space-resolved information at the molecular scale is required but has been lacking due to experimental difficulties. We succeeded in the real-time mapping of the vibrational energy flow in a protein with the spatial resolution of a single amino acid residue by combining time-resolved resonance Raman spectroscopy and site-directed single-Trp mutagenesis. Anti-Stokes Raman intensities of the Trp residues at different sites exhibited different temporal evolutions, reflecting propagation of the energy released by the heme group. A classical heat transport model was not able to reproduce the entire experimental data set, showing that we need a molecular-level description to explain the energy flow in a protein. The systematic application of our general methodology to proteins with different structural motifs may provide a greatly increased understanding of the energy flow in proteins.