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Title: NEGATIVE-ION MODE NANOELECTROSPRAY TANDEM MASS SPECTROMETRY: POTENTIAL TO IMPROVE THE DETECTION OF PATHOGEN PROTEINS

Author
item PADLIYA, NEERAV - 1275-31-00
item Cooper, Bret
item WOOD, TROY - UNIVERSITY OF BUFFALO

Submitted to: Journal of American Society for Mass Spectrometry
Publication Type: Abstract Only
Publication Acceptance Date: 3/5/2005
Publication Date: 3/5/2005
Citation: Padliya, N., Cooper, B., Wood, T. 2005. Negative-ion mode nanoelectrospray tandem mass spectrometry: potential to improve the detection of pathogen proteins. Journal of American Society for Mass Spectrometry 1: S2-S169.

Interpretive Summary:

Technical Abstract: Our laboratory is interested in elucidating the proteome of Uromyces appendiculatus, the causal agent of common bean rust. Knowledge of the proteins that form uredospores, germlings, appressoria, and haustoria may be used to define host-pathogen interactions. We have produced more than 55,000 tandem mass spectra from U. appendiculatus. However, many of the collected spectra are of “poor quality” and the resulting interpretation by Mascot can result in a high occurrence of false positive matches. We hypothesize that experimentation in the negative-ion mode may reduce the likelihood of false positive matches that arise “poor quality” spectra. Negative-ion mode nanoelectrospray mass spectrometry is a very under-utilized tool in the structural characterization of peptides. Its under-utilization stems from the fact that traditional gold-coated nanoelectrospray emitters have a tendency to undergo electrical discharge when operated in the negative-ion mode. Nevertheless, this electrical discharge is not observed when the nanoelectrospray experiment is carried out using a polyaniline-coated nanoelectrospray emitter. Due to different charge localization effects that occur in the negative-ion mode, we have found that many peptide ion fragments are found to be generated exclusively in the negative-ion mode experiment. In addition, negative-ion mode tandem mass spectra contain less chemical background and hence are easier to interpret. We have demonstrated that negative-ion mode nanoelectrospray mass spectrometry has remarkable potential to reduce false positive rates and improve our analysis of the proteome of U. appendiculatus.