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Eur. J. Mass Spectrom. DOI: 10.1255/ejms.588 |
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Characterization and de Novo Sequencing of Atlantic Salmon Vitellogenin Protein by Elctrospray Tandem and Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry | ||
Joseph Banoub |
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ABSTRACT: | ||
ABSTRACT: Vitellogenin (VTG) is a protein produced by the liver of oviparous animals in response to circulating estrogens. In the plasma of males and immature females, VTG is undetectable. VTG has been used as a biomarker for exposure to endocrine disruptors in many species. In the present study, characterization of intact Atlantic Salmon VTG was done by matrix-assisted laser desorption/ionization-Time-of-flight mass spectrometry (MALDI-TOF-MS). Tryptic digest peptides were analyzed by MALDI-TOF-MS to obtain a peptide mass fingerprint. De Novo sequencing of the tryptic peptides was performed by low energy collisionally induced dissociation (CID) using an electrospray ionization-quadrupole-TOF orthogonal hybrid mass spectrometer (ESI-Q-TOF-MS/MS). The interpretation of the product ion spectra obtained from the ESI-Q-TOF-MS/MS was done by Lutefisk, a computer based software algorithm. The molecular mass of the intact protein was found to be 187335 Da. A total of fourteen tryptic peptides were sequenced and compared to the complete Rainbow Trout VTG and to the partial Atlantic Salmon VTG sequences found in the Swiss-Prot database. De Novo sequencing by CID-MS/MS of eleven Atlantic Salmon tryptic digest peptides of selected precursor ions at m/z 788.24, 700.20, 794.75, 834.31, 889.28, 819.79, 865.27, 843.81, 572.20, 573.66 and 561.68 showed high homology with the known sequence of Rainbow Trout VTG. The last two precursor peptide ions, found at m/z 573.66 and m/z 561.68 also specifically matched the known portion of the Atlantic Salmon VTG sequence. Finally, three tryptic precursor peptide ions found at m/z 795.18, 893.28 and 791.05, provided product ion spectra, which were exclusive to the unsequenced portion of the Atlantic Salmon VTG | ||
Keywords: Vitellogenin, Characterization, Ecotoxicology, Tryptic, Atlantic Salmon, Mass spectrometry, De Novo, Sequencing |
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