Sensitivity-Enhanced Static 15N NMR of Solids by 1H Indirect Detection

✍ Scribed by Mei Hong; Satoru Yamaguchi

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 118 KB
• Volume: 150
• Category: Article
• ISSN: 1090-7807
• DOI: 10.1006/jmre.2001.2309

✦ Synopsis

A method for enhancing the sensitivity of 15 N spectra of nonspinning solids through 1 H indirect detection is introduced. By sampling the 1 H signals in the windows of a pulsed spin-lock sequence, highsensitivity 1 H spectra can be obtained in two-dimensional (2D) spectra whose indirect dimension yields the 15 N chemical shift pattern. By sacrificing the 1 H chemical shift information, sensitivity gains of 1.8 to 2.5 for the 15 N spectra were achieved experimentally. A similar sensitivity enhancement was also obtained for 2D 15 N-1 H dipolar and 15 N chemical shift correlation spectroscopy, by means of a 3D 1 H/ 15 N-1 H/ 15 N correlation experiment. We demonstrate this technique, termed PRINS for proton indirectly detected nitrogen static NMR, on a crystalline model compound with long 1 H T 1ρ and on a 25-kDa protein with short 1 H T 1ρ . This 1 H indirect detection approach should be useful for enhancing the sensitivity of 15 N NMR of oriented membrane peptides. It can also be used to facilitate the empirical optimization of 15 N-detected experiments where the inherent sensitivity of the sample is low.