Evaluation of protein 15N relaxation times by inverse Laplace transformation

✍ Scribed by Harri Koskela; Ilkka Kilpeläinen; Sami Heikkinen

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 141 KB
• Volume: 42
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1309

✦ Synopsis

Abstract

Relaxation times (T~1~, T~2~, T~1ρ~) are usually evaluated from exponential decay data by least‐squares fitting methods. For this procedure, the integrals or amplitudes of signals must be determined, which can be laborious with large data sets. Moreover, the fitting requires a priori knowledge of the number of exponential components responsible for the decay. We have adapted inverse Laplace transformation (ILT) for the analysis of relaxation data. Exponential components are resolved with ILT to reciprocal space on their corresponding relaxation rate values. The ILT approach was applied to 3D linewidth‐resolved ^15^N HSQC experiments to evaluate ^15^N T~1~ and T~2~ relaxation times of ubiquitin. The resulting spectrum is a true 3D spectrum, where the signals are separated by their ^1^H and ^15^N chemical shifts (HSQC correlations) and by their relaxation rate values (R~1~ or R~2~). From this spectrum, the relaxation times can be obtained directly with a simple peak‐picking procedure. Copyright © 2003 John Wiley & Sons, Ltd.