Abstract:
:High resolution dynamics and structural information has been resolved from 2H solid-state NMR spectra of the Val-1 side-chain of the gramicidin channel in a lipid bilayer. Both powder pattern lineshapes and spectra from uniformly aligned samples of gramicidin in lipid bilayers have been analyzed to achieve a fully consistant interpretation of the data. Torsional motions about the C alpha C beta axis (chi 1) are shown to be three-state jumps in which the occupancy of the states is given by the ratio, 75:15:10 for the chi 1 angles of 184 degrees:304 degrees:64 degrees. The dominant conformer is also the most common conformation observed for valines in well defined protein structures. The distribution of conformational substates that represents the chi 1 dynamics appears to be largely independent of the lipid phase transition and the hydration of the sample. However, there is evidence that the residence time between jumps is dependent on the lipid phase transition. Although this time is shown to be approximately 1 microseconds below the phase transition temperature, it is in the fast exchange limit above the transition temperature.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Lee KC,Cross TAdoi
10.1016/S0006-3495(94)80928-2subject
Has Abstractpub_date
1994-05-01 00:00:00pages
1380-7issue
5eissn
0006-3495issn
1542-0086pii
S0006-3495(94)80928-2journal_volume
66pub_type
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