| Abstract
| - Recently, it has been demonstrated that bacteria can becharacterized using whole cells and matrix-assisted laserdesorption/ionization mass spectrometry (MALDI-MS).However, identification of specific bacterial proteins usually requires analysis of cellular fractions or purifiedextracts. Here, the first application of Fourier transformmass spectrometry (FTMS) to analysis of bacterial proteins directly from whole cells is reported. It is shown thataccurate mass MALDI-FTMS can be used to characterizespecific ribosomal proteins directly from Escherichiacoli cells. High-accuracy mass measurements and high-resolution isotope profile data confirm posttranslationalmodifications proposed previously on the basis of low-resolution mass measurements. Seven ribosomal proteinsfrom E. coli whole cells were observed with errors of lessthan 27 ppm. This was accomplished directly from wholecells without fractionation, concentration, or overt overexpression of characteristic cellular proteins. MALDI-FTMS also provided information regarding E. coli lipidsin the low-mass region. Although ions with m/z valuesbelow 1000 have been observed by FTMS of whole cells,this represents the first report of detection of ions in the5000 to 10 000 m/z range by MALDI-FTMS using wholecells.
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