title: Application of ion mobility tandem mass spectrometry to compositional and structural analysis of glycopeptides extracted from the urine of a patient diagnosed with Schindler disease.
abstract: BACKGROUND
  Schindler disease is caused by the deficient activity of α-N-acetylgalactosaminidase, which leads to an abnormal accumulation of O-glycopeptides in tissues and body fluids. In this work the Schindler condition is for the first time approached by ion mobility (IMS) tandem mass spectrometry (MS/MS), for determining urine glycopeptide fingerprints and discriminate isomeric structures.
  
  
  METHODS
  IMS-MS experiments were conducted on a Synapt G2s mass spectrometer operating in negative ion mode. A glycopeptide mixture extracted from the urine of a patient suffering from Schindler disease was dissolved in methanol and infused into the mass spectrometer by electrospray ionization using a syringe-pump system. MS/MS was performed by collision-induced dissociation (CID) at low energies, after mobility separation in the transfer cell. Data acquisition and processing were performed using MassLynx and Waters Driftscope software.
  
  
  RESULTS
  IMS-MS data indicated that the attachment of one or two amino acids to the carbohydrate backbone has a minimal influence on the molecule conformation, which limits the discrimination of the free oligosaccharides from the glycosylated amino acids and dipeptides. The structural analysis by CID MS/MS in combination with IMS-MS of species exhibiting the same m/z but different configurations demonstrated for the first time the presence of positional isomers for some of the Schindler disease biomarker candidates.
  
  
  CONCLUSIONS
  The IMS-MS and CID MS/MS platform was for the first time optimized and applied to Schindler disease glycourinome. By this approach the separation and characterization of Neu5Ac positional isomers was possible. IMS CID MS/MS showed the ability to determine the type of the glycopeptide isomers from a series of possible candidates.
authors.affiliation: West University of Timisoara, Romania.|Aurel Vlaicu University of Arad, Romania.
authors.forename: Mirela
authors.initials: M
authors.lastname: Sarbu
authors.affiliation: Department of Chemistry, Indiana University, Bloomington, USA.
authors.forename: Feifei
authors.initials: F
authors.lastname: Zhu
authors.affiliation: Institute for Medical Physics and Biophysics, University of Muenster, Germany.|Department of Biotechnology, University of Rijeka, Croatia.
authors.forename: Jasna
authors.initials: J
authors.lastname: Peter-Katalinić
authors.affiliation: Department of Chemistry, Indiana University, Bloomington, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Clemmer
authors.affiliation: Aurel Vlaicu University of Arad, Romania.|National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, Romania.
authors.forename: Alina D
authors.initials: AD
authors.lastname: Zamfir
mesh_terms: D002675:Child, Preschool; D006020:Glycopeptides / Q000737:chemistry* / Q000652:urine*; D006801:Humans; D007536:Isomerism; D016464:Lysosomal Storage Diseases / Q000652:urine*; D008297:Male; D019150:Neuroaxonal Dystrophies / Q000652:urine*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D048809:alpha-N-Acetylgalactosaminidase / Q000172:deficiency* / Q000652:urine
chemical_list: D006020:Glycopeptides; D048809:alpha-N-Acetylgalactosaminidase