Hydration effects on dynamics of polyglycine and sodium poly(L-glutamate).
Solid state nmr methods were applied to the study of the motions and structural heterogeneity in polyglycine, sodium poly(L-glutamate), and poly(L-alanine). The response of both the main-chain and side-chain resonances to the addition of water was studied using static and magic-angle sample-spinning line shapes as well as the carbon spin-lattice relaxation times, the proton spin-lattice relaxation time in the rotating frame, and the proton-carbon cross-polarization time. The polyglycine motions are not drastically affected by the addition of water when the polymer is in the 3(1)-helix or the beta-sheet structure. The sodium poly(L-glutamate), however, responds to increased hydration with little motion in the main-chain carbon atoms, but considerable flexibility of the side-chain atoms. The greatest motions are reported for the C5 carbon with rotational amplitudes about the C4-C5 bond of about of 50 degrees. In addition, motions somewhat less than half this size are required closer to the main chain.
Department of Biophysics, University of Rochester Medical Center, New York 14642.
S D
SD
Kennedy
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Bryant
D010455:Peptides / Q000737:chemistry*; D011099:Polyglutamic Acid / Q000737:chemistry*; D011827:Radiation; D013057:Spectrum Analysis; D014867:Water / Q000737:chemistry
D010455:Peptides; D014867:Water; D011099:Polyglutamic Acid; C011080:polyglycine