A practical implementation of cross-spectrum in protein backbone resonance assignment

作者：Chen Kang; Delaglio Frank; Tjandra Nico^*

来源：Journal of Magnetic Resonance, 2010, 203(2): 208-212.

DOI：10.1016/j.jmr.2009.12.018

• Backbone assignment
• Cross-spectrum
• Heteronuclear experiments
• Automation

The concept of cross-spectrum is applied in protein NMR spectroscopy to assist in the backbone sequential resonance assignment. Cross-spectrum analysis is used routinely to reveal correlations in frequency domains as a means to reveal common features contained in multiple time series. Here the cross-spectrum between related NMR spectra, for example HNCO and HN(CA)CO, can be calculated with point-by-point multiplications along their common C' carbon axis. In the resulting higher order cross-spectrum, an enhanced correlation signal occurs at every common i-1 carbon frequency allowing the amide proton H(N) (and nitrogen N) resonances from residues i and i-1 to be identified. The cross-spectrum approach is demonstrated using 2D spectra H(N)CO, H(NCA)CO, H(NCO)CACB, and H(N)CACB measured on a (15)N/(13)C double-labeled Ubiquitin sample. These 2D spectra are used to calculate two pseudo-3D cross-spectra, H(i)-H(i-1)-C'(i-1) and H(i)-H(i-1)-CA(i-1)CB(i-1). We show using this approach, backbone resonances of H, C', CA, and CB can be fully assigned without ambiguity. The cross-spectrum principle is expected to offer an easy, practical, and more quantitative approach for heteronuclear backbone resonance assignment. Published by Elsevier Inc.

• 出版日期2010-4
• 单位NIH