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Kim, Yung Sam
Ultrafast 2D IR Spectroscopy Lab
Research Interests
  • 2D IR, chemical exchange of H-bond, fast reaction dynamics, protein dynamics


Two-dimensional infrared spectroscopy of isotopomers of an alanine rich alpha-helix

DC Field Value Language Fang, C ko Wang, J ko Kim, Yung Sam ko Charnley, AK ko Barber-Armstrong, W ko Smith, AB ko Decatur, SM ko Hochstrasser, RM ko 2014-11-17T08:12:59Z - 2014-11-14 ko 2004-07 ko
dc.identifier.citation JOURNAL OF PHYSICAL CHEMISTRY B, v.108, no.29, pp.10415 - 10427 ko
dc.identifier.issn 1520-6106 ko
dc.identifier.uri -
dc.description.abstract The two-dimensional infrared spectra of a series of doubly isotopically substituted 25-residue α-helices were measured with femtosecond three pulse infrared time domain interferometry. The insertion of 13C= 16O and 13C= 18O labels at known residues on the helix permitted the vibrational couplings between different amide I' modes separated by one, two, and three residues to be measured. The 2D IR signal of one residue in 25 was readily studied, confirming this approach is applicable to labeled proteins. We identified the couplings between each pair of isotopomer levels and between them and the helix exciton band states: the 2D IR spectra proved that the amide vibrations of the α-helix are delocalized. Cross-peaks, originating from the coupling of the isotopomer pairs, were systematically analyzed. Besides the separated pair modeling and second-order perturbation theory estimates, the experimental results were compared in detail with a full matrix diagonalization simulation based on averaged Hamiltonian matrices that represent the amide I' vibrator's one- and two-exciton states. The main features of the 2D IR spectra could be predicted by this modeling. The experimental results were in good agreement with a set of couplings that were derived from transition chargetransition charge interactions for all but the nearest neighbors, for which the coupling is more influenced by through-bond interactions between the adjacent amide groups. The possible ranges of the magnitudes of the three largest coupling constants β 12, β 13, and β 14 were explored by various approaches to be within a few cm -1 accuracy of a preferred set of absolute values and their associated error bars: |β 12| = 8.5 ± 1.8, |β 13| = 5.4 ± 1.0, and |β 14| = 6.6 ± 0.8 cm -1. The signs were independently indicated to be β 12 > 0, β 13 < 0, and β 14 < 0. ko
dc.description.statementofresponsibility close -
dc.language 영어 ko
dc.publisher AMER CHEMICAL SOC ko
dc.title Two-dimensional infrared spectroscopy of isotopomers of an alanine rich alpha-helix ko
dc.type ARTICLE ko
dc.identifier.scopusid 2-s2.0-3442875856 ko
dc.identifier.wosid 000222763000025 ko
dc.type.rims ART ko
dc.description.wostc 116 *
dc.description.scopustc 113 * 2015-05-06 * 2014-11-14 *
dc.identifier.doi 10.1021/jp0498963y ko
dc.identifier.url ko
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