title: LTQ Orbitrap Velos in routine de novo sequencing of non-tryptic skin peptides from the frog Rana latastei with traditional and reliable manual spectra interpretation.
abstract: BACKGROUND
  Mass spectrometry has shown itself to be the most efficient tool for the sequencing of peptides. However, de novo sequencing of novel natural peptides is significantly more challenging in comparison with the same procedure applied for the tryptic peptides. To reach the goal in this case it is essential to select the most efficient methods of triggering fragmentation and combine all the possible complementary techniques.
  
  
  METHODS
  Collision-induced dissociation (CID), high-energy collision dissociation (HCD), and electron-transfer dissociation (ETD) tandem mass spectra recorded with a LTQ Orbitrap Velos instrument were used for the elucidation of the sequence of the natural non-tryptic peptides from the skin secretion of Rana latastei. Manual interpretation of the spectra was applied.
  
  
  RESULTS
  The combined approach using CID, HCD, and ETD tandem mass spectra of the multiprotonated peptides in various charge states, as well as of their proteolytic fragments, allowed the sequences of seven novel peptides from the skin secretion of Rana latastei to be established.
  
  
  CONCLUSIONS
  Manual mass spectrometry sequencing of natural non-tryptic peptides from the skin secretion of Rana latastei provided the opportunity to work successfully with these species and demonstrated once again its advantage over automatic approaches.
authors.forename: Tatiana Yu
authors.initials: TY
authors.lastname: Samgina
authors.forename: Miriam D
authors.initials: MD
authors.lastname: Tolpina
authors.forename: Polonca
authors.initials: P
authors.lastname: Trebse
authors.forename: Gregor
authors.initials: G
authors.lastname: Torkar
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Artemenko
authors.forename: Jonas
authors.initials: J
authors.lastname: Bergquist
authors.forename: Albert T
authors.initials: AT
authors.lastname: Lebedev
mesh_terms: D000595:Amino Acid Sequence; D029845:Amphibian Proteins / Q000032:analysis* / Q000737:chemistry; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000032:analysis / Q000737:chemistry; D005260:Female; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis / Q000737:chemistry; D011898:Ranidae; D015203:Reproducibility of Results; D020539:Sequence Analysis, Protein / Q000379:methods*; D012867:Skin / Q000737:chemistry*; D053719:Tandem Mass Spectrometry / Q000295:instrumentation* / Q000379:methods*
chemical_list: D029845:Amphibian Proteins; D023181:Antimicrobial Cationic Peptides; D010455:Peptides; C078413:brevinin-1 protein, Rana; C078414:brevinin-2, Rana