Peptide dynamics in solution
Analytical Chemistry and Spectroscopy
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
The dynamic behaviour of [Lys8]-vasopressin derivatives, especially of N-Gly-Gly-Gly-[Lys8]-vasopressin in solution, was investigated by NMR relaxation studies. One can derive a set of dynamics data which describe the molecular tumbling in solution from 13C spin-lattice relaxation times, T1, spin-spin relaxation times, T2, and heteronuclear nuclear Overhauser enhancements (NOE). Two different approaches, the scheme proposed by Jardetzky and co-workers and the ‘model-free’ approximation of Lipari and Szabo, are used to analyse the dynamics and a comparison of the corresponding data is given. In addition to a mobility of 108-109 s-1, we observe a faster mobility of the order of 109-1010 s-1 in addition to slow dynamic contributions. The latter can be associated by means of T1, measurements with a motion involving the S—S linkage in the vasopressin. Some additional motion is described as the overall mobility of an associate. The results from 13C relaxation were corroborated by 15N T1 measurements, performed at the 15N natural abundance level by an INEPT-reverse INEPT method, and by 15N NOE investigations.
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