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Intact Protein Profiling of Chlorobium tepidum by Capillary Isoelectric Focusing, Reversed-Phase Liquid Chromatography, and Mass Spectrometry

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journal contribution
posted on 15.09.2007, 00:00 by Feng Zhou, Thomas E. Hanson, Murray V. Johnston
Capillary isoelectric focusing (CIEF) coupled with reversed-phase liquid chromatography (RPLC) and electrospray ionization (ESI) mass spectrometry (MS) is shown to provide a liquid-based alternative to 2D-PAGE for intact protein profiling. This combination exhibits high resolution, sensitivity and throughput for protein profiling based on pI vs MW. The CIEF-RPLC−MS system described here facilitates the use of IEF markers for internal calibration of pI. It also provides a high dynamic range as evidenced by the detection of 100 pg (3 fmol) of a test protein spiked into 1 μg of a complex protein mixture. About 1200 individual proteins/polypeptides were detected from lysates of the green sulfur bacterium Chlorobium tepidum in a single <8 h run. The pI vs MW profile obtained from CIEF-RPLC−MS compares favorably with theoretical data derived from the C. tepidum genome and experimental data obtained from 2D-PAGE.