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Reorientational dynamics and internal mobility of [Lys 8 ]‐vasopressins by analysis of 13 C, 15 N and 1 H NMR relaxation
Author(s) -
Zieger G.,
Sterk H.
Publication year - 1992
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260300506
Subject(s) - chemistry , heteronuclear molecule , relaxation (psychology) , nuclear overhauser effect , spin–lattice relaxation , molecular dynamics , spin–spin relaxation , nuclear magnetic resonance spectroscopy , dynamics (music) , nuclear magnetic resonance , crystallography , computational chemistry , stereochemistry , physics , nuclear quadrupole resonance , psychology , social psychology , acoustics
The dynamic behaviour of [Lys 8 ]‐vasopressin derivatives, especially of N ‐Gly‐Gly‐Gly‐[Lys 8 ]‐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 13 C spin–lattice relaxation times, T 1 , spin–spin relaxation times, T 2 , 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 10 8 –10 9 s −1 , we observe a faster mobility of the order of 10 9 –10 10 s −1 in addition to slow dynamic contributions. The latter can be associated by means of T 1 , measurements with a motion involving the SS linkage in the vasopressin. Some additional motion is described as the overall mobility of an associate. The results from 13 C relaxation were corroborated by 15 N T 1 measurements, performed at the 15 N natural abundance level by an INEPT–reverse INEPT method, and by 15 N NOE investigations.