Identification of Water-Soluble Selenium-Containing Proteins in Selenized Yeast by Size-Exclusion-Reversed-Phase HPLC/ICPMS Followed by MALDI-TOF and Electrospray Q-TOF Mass Spectrometry
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- 作者：Jorge Ruiz Encinar ; Laurent Ouerdane ; William Buchmann ; Jeanine Tortajada ; Ryszard Lobinski ; and Joanna Szpunar
- 刊名：Analytical Chemistry
- 出版年：2003
- 出版时间：August 1, 2003
- 年：2003
- 卷：75
- 期：15
- 页码：3765 - 3774
- 全文大小：333K
- 年卷期：v.75,no.15(August 1, 2003)
- ISSN：1520-6882
文摘
An approach to speciation of selenium incorporated inyeast proteins was developed. The tryptic digest of a water-soluble protein fraction isolated by size-exclusion chromatography was analyzed by reversed-phase HPLC/ICPMS. The selenopeptides selected owing to the detector'selemental specificity were then analyzed by MALDI-TOFMS in order to select target ions for collision-induceddissociation MS. The latter, carried out with an electrospray Q-TOF spectrometer, enabled the sequencing of theselenopeptides detected by HPLC/ICPMS. The approachallowed for the first time the identification of a family ofSe-containing proteins resulting from the replacement byselenomethionine of 2-9 methionine residues in a salt-stress-induced protein SIP18 (Mr 8874). The presenceof these proteins was confirmed by MALDI-TOFMS of theoriginal (nondigested) protein fraction. Another seleniumprotein identified was a heat-shock protein HSP12(Mr 11 693) in which the only methionine residue wasreplaced by selenomethionine. These two Se-containingproteins accounted for more than 95% of selenium in thewater-soluble protein fraction.