Temperature dependence of fast carbonyl backbone dynamics in chicken villin headpiece subdomain
 

Temperature dependence of fast carbonyl backbone dynamics in chicken villin headpiece subdomain


Abstract Temperature-dependence of protein dynamics can provide information on details of the free energy landscape by probing the characteristics of the potential responsible for the fluctuations. We have investigated the temperature-dependence of picosecond to nanosecond backbone dynamics at carbonyl carbon sites in chicken villin headpiece subdomain protein using a combination of three NMR relaxation rates: 13Câ?² longitudinal rate, and two cross-correlated rates involving dipolar and chemical shift anisotropy (CSA) relaxation mechanisms, 13Câ?²/13Câ?²-13Cα CSA/dipolar and 13Câ?²/13Câ?²â??15N CSA/dipolar. Order parameters have been extracted using the Lipari-Szabo model-free approach assuming a separation of the time scales of internal and molecular motions in the 2â??16°C temperature range. There is a gradual deviation from this assumption from lower to higher temperatures, such that above 16°C the separation of the time scales is inconsistent with the experimental data and, thus, the Lipari-Szabo formalism can not be applied. While there are variations among the residues, on the average the order parameters indicate a markedly steeper temperature dependence at backbone carbonyl carbons compared to that probed at amide nitrogens in an earlier study. This strongly advocates for probing sites other than amide nitrogen for accurate characterization of the potential and other thermodynamics characteristics of protein backbone.

• Content Type Journal Article
• Pages 1-9
• DOI 10.1007/s10858-011-9500-x
• Authors
  • Liliya Vugmeyster, Department of Chemistry and Environment and Natural Resources Institute, University of Alaska at Anchorage, 3211 Providence Drive, Anchorage, AK 99508, USA
  • Dmitry Ostrovsky, Department of Mathematical Sciences, University of Alaska at Anchorage, 3211 Providence Drive, Anchorage, AK 99508, USA

• • Journal Journal of Biomolecular NMR
  • Online ISSN 1573-5001
  • Print ISSN 0925-2738

Source: Journal of Biomolecular NMR