TROSY-based NMR experiments for NMR studies of large biomolecules Guang Zhu a, * , Xuejun Yao b a Department of Biochemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, SAR, PR China b Department of Physics, East China Normal University, Shanghai, PR China Received 8 August 2007; accepted 17 October 2007 Available online 1 November 2007 Keywords: TROSY; NMR of large biomolecules; ZQ-TROSY; SQ-TROSY Contents 1. Introduction ............................................................................... 49 2. Background................................................................................ 50 2.1. Single-quantum TROSY .................................................................. 50 2.2. Zero-quantum TROSY ................................................................... 53 3. TROSY-based experiments for chemical shift assignments ............................................... 54 3.1. TROSY-based HNCA experiment ........................................................... 54 3.2. TROSY-based experiments for chemical shift assignments of 15 N/ 13 C-labeled proteins ...................... 55 3.3. Application of TROSY-based experiments for protein backbone assignment ............................. 56 4. TROSY-based NOESY experiments .............................................................. 56 4.1. Single-quantum NOESY-TROSY ............................................................ 56 4.2. Zero-quantum NOESY-TROSY ............................................................. 59 5. TROSY-based experiments for coupling measurements ................................................. 59 5.1. TROSY experiments for H-bond coupling measurements ........................................... 59 5.2. TROSY experiments for residual dipolar coupling measurements ..................................... 60 5.3. TROSY experiments for J-coupling measurements ................................................ 62 6. TROSY-based experiments for NMR studies of protein dynamics and amide proton exchange..................... 63 6.1. Protein dynamics measurement by TROSY-based experiments ....................................... 63 6.2. SEA-TROSY .......................................................................... 65 7. Summary ................................................................................. 66 Acknowledgement ........................................................................... 66 References ................................................................................. 66 1. Introduction Nuclear magnetic resonance (NMR) spectroscopy is the most powerful spectroscopic tool for structure–function studies of biological macromolecules in solution. Conven- tional multidimensional NMR spectroscopic methods developed before 1997 were limited to the study of proteins smaller than 25 and 60 kDa for 13 C/ 15 N and 2 H/ 13 C/ 15 N- labeled proteins, respectively [1–3]. The introduction of Transverse Relaxation Optimized Spectroscopy (TRO- SY)-based NMR methods [4–9] opened new avenues for the structural determination of much larger biological macromolecules, particularly proteins and nucleic acids. 0079-6565/$ - see front matter Ó 2007 Published by Elsevier B.V. doi:10.1016/j.pnmrs.2007.10.001 * Corresponding author. Fax: +852 2358 1552. E-mail address: gzhu@ust.hk (G. Zhu). www.elsevier.com/locate/pnmrs Progress in Nuclear Magnetic Resonance Spectroscopy 52 (2008) 49–68