Direct observation of self-trapped vibrational states in alpha-helices

Femtosecond infrared pump-probe spectroscopy of the N-H mode of a stable alpha-helix reveals two excited-state absorption bands, which disappear upon unfolding of the helix. A quantitative comparison with polaron theory shows that these two bands reflect two types of two-vibron bound states connecte...

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Bibliographic Details
Published inPhysical review letters Vol. 93; no. 10; p. 106405
Main Authors Edler, J, Pfister, R, Pouthier, V, Falvo, C, Hamm, P
Format Journal Article
LanguageEnglish
Published United States 03.09.2004
Subjects
Amino Acids - chemistry
Computer Simulation
Hydrogen Bonding
Models, Chemical
Models, Molecular
Nitrogen - chemistry
Polyglutamic Acid - analogs & derivatives
Polyglutamic Acid - chemistry
Protein Structure, Secondary
Spectrophotometry, Infrared - methods
Vibration
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Summary:Femtosecond infrared pump-probe spectroscopy of the N-H mode of a stable alpha-helix reveals two excited-state absorption bands, which disappear upon unfolding of the helix. A quantitative comparison with polaron theory shows that these two bands reflect two types of two-vibron bound states connected to the trapping of two vibrons at the same site and at nearest neighbor sites, respectively. The latter states originate from an acoustic phonon in the helix, which correlates adjacent sites.
ISSN:0031-9007
DOI:10.1103/PhysRevLett.93.106405