Reference : Peptide backbone fragmentation initiated by side-chain loss at cysteine residue in ma...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Chemistry
http://hdl.handle.net/2268/148791
Peptide backbone fragmentation initiated by side-chain loss at cysteine residue in matrixassisted laser desorption/ionization in-source decay mass spectrometry
English
Asakawa, Daiki mailto []
Smargiasso, Nicolas mailto [Université de Liège - ULiège > Département de chimie (sciences) > GIGA-R : Laboratoire de spectrométrie de masse (L.S.M.) >]
Quinton, Loïc mailto [Université de Liège - ULiège > Département de chimie (sciences) > Chimie biologique >]
De Pauw, Edwin mailto [Université de Liège - ULiège > Département de chimie (sciences) > GIGA-R : Laboratoire de spectrométrie de masse (L.S.M.) >]
2013
Journal of Mass Spectrometry
John Wiley & Sons, Inc
48
352-360
Yes (verified by ORBi)
International
1076-5174
Chichester
United Kingdom
[en] Top-down sequencing ; In-source decay ; 1,5-diaminonapthalene
[en] Matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) is initiated by hydrogen transfer from matrix molecules to the carbonyl oxygen of peptide backbone with subsequent radical-induced cleavage leading to c0/z• fragments pair. MALDI-ISD is a very powerful method to obtain long sequence tags from proteins or to do de novo sequencing of peptides. Besides classical fragmentation, MALDI-ISD also shows specific fragments for which the mechanism of formation enlightened the MALDI-ISD process. In this study, the MALDI-ISD mechanism is reviewed, and a specific mechanism is studied in details: the N-terminal side of Cys residue (Xxx-Cys) is described to promote the generation of c0 and w fragments in MALDI-ISD. Our data suggest that for sequences containing Xxx-Cys motifs, the N–Ca bond cleavage occurs following the hydrogen attachment to the thiol group of Cys side-chain. The c•/w fragments pair is formed by side-chain loss of the Cys residue with subsequent radical-induced cleavage
at the N–Ca bond located at the left side (N-terminal direction) of the Cys residue. This fragmentation pathway preferentially
occurs at free Cys residue and is suppressedwhen the cysteines are involved in disulfide bonds. Hydrogen attachment to alkylated Cys residues using iodoacetamide gives free Cys residue by the loss of •CH2CONH2 radical. The presence of alkylated Cys residue also suppress the formation of c•/w fragments pair via the (Cb)-centered radical, whereas w fragment is still observed as intense signal. In this case, the z• fragment formed by hydrogen attachment of carbonyl oxygen followed side-chain loss at alkylated Cys leads to a w fragment. Hydrogen attachment on peptide backbone and side-chain of Cys residue occurs therefore competitively
during MALDI-ISD process.
Researchers ; Professionals
http://hdl.handle.net/2268/148791
10.1002/jms.3182

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