Dubey Abhinav, Mondal Somnath, Chandra Kousik, Atreya Hanudatta S
IISc Mathematics Initiative, Indian Institute of Science, Bangalore 560012, India; NMR Research Centre, Indian Institute of Science, Bangalore 560012, India.
NMR Research Centre, Indian Institute of Science, Bangalore 560012, India; Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India.
J Magn Reson. 2016 Jun;267:22-9. doi: 10.1016/j.jmr.2016.04.004. Epub 2016 Apr 7.
We present a simple approach to rapidly identify amino acid types in proteins from a 2D spectrum. The method is based on the fact that (13)C(β) chemical shifts of different amino acid types fall in distinct spectral regions. By evolving the (13)C chemical shifts in the conventional HNCACB or HN(CO)CACB type experiment for a single specified delay period, the phase of the cross peaks of different amino acid residues are modulated depending on their (13)C(β) shift values. Following this specified evolution period, the 2D HN projections of these experiments are acquired. The (13)C evolution period can be chosen such that all residues belonging to a given set of amino acid types have the same phase pattern (positive or negative) facilitating their identification. This approach does not require the preparation of any additional samples, involves the analysis of 2D [(15)N-(1)H] HSQC-type spectra obtained from the routinely used triple resonance experiments with minor modifications, and is applicable to deuterated proteins. The method will be useful for quick assignment of signals that shift during ligand binding or in combination with selective labeling/unlabeling approaches for identification of amino acid types to aid the sequential assignment process.
我们提出了一种简单的方法，可从二维谱图中快速识别蛋白质中的氨基酸类型。该方法基于不同氨基酸类型的（13）C（β）化学位移落在不同光谱区域这一事实。通过在传统的HNCACB或HN（CO）CACB类型实验中，将（13）C化学位移在单个指定延迟期内进行演化，不同氨基酸残基交叉峰的相位会根据其（13）C（β）位移值进行调制。在这个指定的演化期之后，获取这些实验的二维HN投影。可以选择（13）C演化期，使得属于给定氨基酸类型集合的所有残基具有相同的相位模式（正或负），便于它们的识别。这种方法不需要制备任何额外的样品，涉及对从常规使用的三共振实验中获得的二维[（15）N - （1）H] HSQC型谱图进行分析，只需进行少量修改，并且适用于氘代蛋白质。该方法将有助于快速确定在配体结合过程中发生位移的信号，或与选择性标记/去标记方法结合使用，以识别氨基酸类型，辅助序列归属过程。
