Use of double-depleted 13C and 15N culture media for analysis of whole cell bacteria by MALDI time-of-flight and Fourier transform mass spectrometry.
In the present paper, results demonstrating the significant advantages of matrix-assisted laser desorption/ionization (MALDI) analysis of whole cell samples of bacteria grown on double isotopically-depleted (13C and 15N) media are presented. It is shown that several advantages accrue for MALDI with a 9.4 T Fourier transform mass spectrometer (FTMS). Of particular note, for analysis of whole cells, sample preparation is simple and chemical interference is reduced. Moreover, ion coalescence problems are minimized, and data-base identification of proteins facilitated. Furthermore, high resolution mass spectra obtained from such whole cells show significant improvement in apparent mass resolving power and mass measurement accuracy, whether time-of-flight or FTMS MALDI is used. As a consequence, it becomes possible to detect subtle details in the chemistry of the organism, such as the presence of both post-translationally modified and unmodified versions of the same proteins. This approach is also adaptable to direct assay of over-expressed proteins from Escherichia coli cultures and should facilitate studies aimed at the detection of medically important cellular biomarker proteins.
Stump
Michael J
MJ
Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA.
Jones
Jeffrey J
JJ
Fleming
Richard C
RC
Lay
Jackson O
JO
Wilkins
Charles L
CL
D001419:Bacteria / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry; D002138:Calibration; D002247:Carbon Isotopes / Q000032:analysis; D003470:Culture Media / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry; D004926:Escherichia coli / Q000737:chemistry; D005583:Fourier Analysis; D009587:Nitrogen Isotopes / Q000032:analysis; D012270:Ribosomes / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D001426:Bacterial Proteins; D002247:Carbon Isotopes; D003470:Culture Media; D004268:DNA-Binding Proteins; D009587:Nitrogen Isotopes