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1: Science. 2006 Oct 6;314(5796):109-12.Click here to read Links
Comment in:
Science. 2006 Oct 6;314(5796):65-6.

Extending top-down mass spectrometry to proteins with masses greater than 200 kilodaltons.

Han X, Jin M, Breuker K, McLafferty FW.

Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY 14853, USA.

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 approximately 500-residue, approximately 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).

PMID: 17023655 [PubMed - indexed for MEDLINE]