Direct Evidence of the Amino Acid Side Chain and Backbone Contributions to Protein Anharmonicity

Giorgio Schiro', Antonio Cupane, Chiara Caronna, Francesca Natali

Risultato della ricerca: Articlepeer review

63 Citazioni (Scopus)

Abstract

Elastic incoherent neutron scattering has been used to study the temperature dependence of the mean-square displacements of nonexchangeable hydrogen atoms in powders of a series of homomeric polypeptides (polyglycine, polyalanine, polyphenylalanine and polyisoleucine) in comparison with myoglobin at the same hydration level (h = 0.2). The aim of the work was to measure the dynamic behavior of different amino acid residues separately and assess the contribution of each type of side chain to the anharmonic dynamics of proteins. The results provide direct experimental evidence that the first anharmonic activation, at similar to 150 K, is largely due to methyl group rotations entering the time window of the spectrometer used; however, contributions on the order of 10-20% from the motions of other groups (e.g., the phenolic ring and the methylene groups) are present. Our data also indicate that the dynamical transition occurring at similar to 230 K can be attributed, at least at the hydration level investigated, mainly to motions involving backbone fluctuations.
Lingua originaleEnglish
pagine (da-a)1371-1376
Numero di pagine7
RivistaJournal of the American Chemical Society
Volume132
Stato di pubblicazionePublished - 2010

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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