Extending Top-Down Mass Spectrometry to Proteins with Masses Greater Than 200 Kilodaltons
Abstract
For characterization of sequence and posttranslational modifications, molecular and fragment ion mass data from ionizing and dissociating a protein in the mass spectrometer are far more specific than are masses of peptides from the protein's digestion. We extend the ~500-residue, ~50-kilodalton (kD) dissociation limitation of this top-down methodology by using electrospray additives, heated vaporization, and separate noncovalent and covalent bond dissociation. This process can cleave 287 interresidue bonds in the termini of a 1314-residue (144-kD) protein, specify previously unidentified disulfide bonds between 8 of 27 cysteines in a 1714-residue (200-kD) protein, and correct sequence predictions in two proteins, one with 2153 residues (229 kD).
- Publication:
-
Science
- Pub Date:
- October 2006
- DOI:
- 10.1126/science.1128868
- Bibcode:
- 2006Sci...314..109H
- Keywords:
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- CHEMISTRY