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.
Kennedy
S D
SD
Department of Biophysics, University of Rochester Medical Center, New York 14642.
Bryant
R G
RG
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