Top-down proteomics

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Top-down proteomics is a method of protein identification that uses an ion trapping mass spectrometer to store an isolated protein ion for mass measurement and tandem mass spectrometry analysis.[1][2] The name is derived from the similar approach to DNA sequencing.[3] Proteins are typically ionized by electrospray ionization and trapped in a Fourier transform ion cyclotron resonance (Penning trap)[4] or quadrupole ion trap (Paul trap) mass spectrometer. Fragmentation for tandem mass spectrometry is accomplished by electron-capture dissociation or electron-transfer dissociation.

Recently, a top-down approach has been developed for mapping the connectivity of the disulfide-rich peptide hedyotide B2.[5] This method allows rapid characterization of the disulfide pattern of cystine-knot miniproteins such as cyclotides, conotoxin, knottin and plant defensins.

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  1. ^ Sze SK, Ge Y, Oh H, McLafferty FW (2002). "Top-down mass spectrometry of a 29-kDa protein for characterization of any posttranslational modification to within one residue". Proc. Natl. Acad. Sci. U.S.A. 99 (4): 1774–9. Bibcode:2002PNAS...99.1774S. doi:10.1073/pnas.251691898. PMC 122269. PMID 11842225. 
  2. ^ Kelleher NL (2004). "Top-down proteomics". Anal. Chem. 76 (11): 197A–203A. doi:10.1021/ac0415657. PMID 15190879. 
  3. ^ Smith CL, Cantor CR (1989). "Evolving strategies for making physical maps of mammalian chromosomes". Genome 31 (2): 1055–8. doi:10.1139/g89-181. PMID 2698822. 
  4. ^ Bogdanov B, Smith RD (2005). "Proteomics by FTICR mass spectrometry: top down and bottom up". Mass spectrometry reviews 24 (2): 168–200. doi:10.1002/mas.20015. PMID 15389855. 
  5. ^ Nguyen GK, Zhang S, Wang W, Wong CT, Nguyen NT, Tam JP: Discovery of a linear cyclotide from the bracelet subfamily and its disulfide mapping by top-down mass spectrometry. J Biol Chem.