Reorientational dynamics and internal mobility of [Lys8]-vasopressins by analysis of 13C, 15N and 1H NMR relaxation

✍ Scribed by G. Zieger; H. Sterk

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 474 KB
• Volume: 30
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260300506

✦ Synopsis

Abstract

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 SS 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.