High flow-resolution for mobility estimation in 2D-ENMR of proteins using maximum entropy method (MEM-ENMR) Journal Article
| Authors: | Thakur, S. B.; He, Q. |
| Article Title: | High flow-resolution for mobility estimation in 2D-ENMR of proteins using maximum entropy method (MEM-ENMR) |
| Abstract: | Multidimensional electrophoretic NMR (nD-ENMR) is a potentially powerful tool for structural characterization of co-existing proteins and protein conformations. By applying a DC electric field pulse, the electrophoretic migration rates of different proteins were detected experimentally in a new dimension of electrophoretic flow. The electrophoretic mobilities were employed to differentiate protein signals. In U-shaped ENMR sample chambers, individual protein components in a solution mixture followed a cosinusoidal electrophoretic interferogram as a function of its unique electrophoretic migration rate. After Fourier transformation in the electrophoretic flow dimension, the protein signals were resolved at different resonant frequencies proportional to their electrophoretic mobilities. Currently, the mobility resolution of the proteins in the electrophoretic flow dimension is limited by severe truncations of the electrophoretic interferograms due to the finite electric field strength available before the onset of heat-induced convection. In this article, we present a successful signal processing method, the Burg's maximum entropy method (MEM), to analyze the truncated ENMR signals (MEM-ENMR). Significant enhancement in flow resolution was demonstrated using two-dimensional ENMR of two protein samples: a lysozyme solution and a solution mixture of bovine serum albumin (BSA) and ubiquitin. The electrophoretic mobilities of lysozyme, BSA and ubiquitin were measured from the MEM analysis as 7.5 × 10-5, 1.9 × 10-4 and 8.7 × 10-5 cm2 V-1 s-1, respectively. Results from computer simulations confirmed a complete removal of truncation artifacts in the MEM-ENMR spectra with 3- to 6-fold resolution enhancement. © 2006 Elsevier Inc. All rights reserved. |
| Keywords: | methodology; proteins; protein; radiation exposure; evaluation; magnetic resonance spectroscopy; nuclear magnetic resonance spectroscopy; computer simulation; models, molecular; chemical structure; electromagnetic field; electromagnetic fields; motion; nuclear magnetic resonance; models, chemical; electrophoresis; conformations; chemical model; entropy; bos taurus; burg's maximum entropy method (mem); electrophoretic nmr (enmr); flow-resolution enhancement; heat-induced convection in enmr; nmr signal separation of co-existing proteins; electric field effects; flow resolution enhancement; heat-induced convection |
| Journal Title: | Journal of Magnetic Resonance |
| Volume: | 183 |
| Issue: | 1 |
| ISSN: | 1090-7807 |
| Publisher: | Academic Press Inc., Elsevier Science |
| Date Published: | 2006-11-01 |
| Start Page: | 32 |
| End Page: | 40 |
| Language: | English |
| DOI: | 10.1016/j.jmr.2006.07.009 |
| PUBMED: | 16901738 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 2" - "Export Date: 4 June 2012" - "Source: Scopus" |
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