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Ultrafast Vibrational Dynamics of Membrane‐Bound Peptides at the Lipid Bilayer/Water Interface
Author(s) -
Tan Junjun,
Zhang Baixiong,
Luo Yi,
Ye Shuji
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201706996
Subject(s) - vibrational energy relaxation , chemistry , bilayer , lipid bilayer , hydrogen bond , rotational–vibrational coupling , relaxation (psychology) , infrared spectroscopy , membrane , chemical physics , crystallography , spectroscopy , molecular vibration , femtosecond , amide , analytical chemistry (journal) , molecule , organic chemistry , psychology , social psychology , biochemistry , physics , quantum mechanics , laser , optics
Abstract Vibrational energy transfer (VET) of proteins at cell membrane plays critical roles in controlling the protein functionalities, but its detection is very challenging. By using a surface‐sensitive femtosecond time‐resolved sum‐frequency generation vibrational spectroscopy with infrared pump, the detection of the ultrafast VET in proteins at cell membrane has finally become possible. The vibrational relaxation time of the N−H groups is determined to be 1.70(±0.05) ps for the α‐helix located in the hydrophobic core of the lipid bilayer and 0.9(±0.05) ps for the membrane‐bound β‐sheet structure. The N−H groups with strong hydrogen bonding gain faster relaxation time. By pumping the amide A band and probing amide I band, the vibrational relaxation from N−H mode to C=O mode through two pathways (direct coupling and through intermediate states) is revealed. The ratio of the pathways depends on the NH⋅⋅⋅O=C hydrogen‐bonding strength. Strong hydrogen bonding favors the coupling through intermediate states.