Freezing of Dynamics of a Methyl Group in a Protein Hydrophobic Core at Cryogenic Temperatures by Deuteron NMR Spectroscopy
Proteins undergo a number of changes when their temperature is dropped from the physiological range to much lower values. One of the most well-known dynamical changes undergone by proteins in a solid state is a so-called protein glass-transition, which is a dynamic transition occurring at about 200-230K leading to a loss of biological activity.1,2 X-ray diffraction, neutron scattering studies, and dielectric spectroscopy, as well as evidence from NMR relaxation measurements, indicate freezing of slow collective modes of motion below the glass transition temperature.3-8 Various arguments have been presented that connect the transition to solvent participation.1,4,8-10 In addition to the solvent-related modes that are frozen below the glass-transition temperature, there are anharmonic motions at temperatures below 200K which are likely to be dominated by methyl group dynamics down to about 100K.2,5,7 Recent neutron-scattering and NMR studies emphasize the role of these modes in low temperature dynamics. 2,5,7,11,12 One of the latest works on the subject by Bajaj et al.11 has reported a structural transition associated with dynamic processes in a solvent-free polypeptide. Thus, protein dynamics at low temperatures are complex and more studies are required to discern their pattern.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 979487
- Report Number(s):
- PNNL-SA-69606; JACSAT; 34295; KP1704020; TRN: US201010%%713
- Journal Information:
- Journal of the American Chemical Society, 132(12):4038-4039, Vol. 132, Issue 12; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
Similar Records
Redox-Promoting Protein Motions in Rubredoxin
Redox-Promoting Protein Motions in Rubredoxin