Identification and structural characterization of novel O- and N-glycoforms in the urine of a Schindler disease patient by Orbitrap mass spectrometry.
Schindler disease is an inherited metabolic disorder caused by the deficient activity of α-N-acetylgalactosaminidase enzyme. An accurate diagnosis requires, besides clinical examination, complex and costly biochemical and molecular genetic tests. In the last years, mass spectrometry (MS) based on nanofluidics and high-resolution instruments has become a successful alternative for disease diagnosis based on the investigation of O-glycopeptides in patient urine. A complex mixture of glycoforms extracted from the urine of a 3-year-old patient was investigated by Orbitrap MS equipped with Nanospray Flex Ion Source in the negative ion mode. For structural characterization of several molecular species, collision-induced dissociation MS2-MS3was carried out using collision energy values within 20-60 eV range. By our approach, 39 novel species associated to this condition were identified, among which O-glycopeptides, free O-glycans and one structure corresponding to an N-glycan never characterized in the context of Schindler disease. The experiments conducted at a resolution of 60 000 allowed the discrimination and identification of a total number of 69 different species with an average mass accuracy of 9.87 ppm, an in-run reproducibility of almost 100%, an experiment-to-experiment and day-to-day reproducibility of about 95%. This study brings contributions in the diagnosis of Schindler disease through the elucidation of potential biomarker species in urine. Our multistage MS results completed with 39 new glycoforms the inventory of potential biomarker structures associated to Schindler disease. For the first time, an N-glycan was identified and structurally characterized in Schindler patient urine, which opens new research directions in the field. Copyright © 2015 John Wiley & Sons, Ltd.
West University of Timisoara, Timisoara, Romania.|Aurel Vlaicu University of Arad, Arad, Romania.
Mirela
M
Sarbu
Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania.
Cristian V A
CV
Munteanu
Psychiatry Discipline, Department of Neuroscience, Victor Babes University of Medicine and Pharmacy, Timisoara, Romania.
Liana
L
Dehelean
Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania.
Andrei J
AJ
Petrescu
Westfälische Wilhelms University of Münster, Münster, Germany.|University of Rijeka, Rijeka, Croatia.
Jasna
J
Peter-Katalinic
Aurel Vlaicu University of Arad, Arad, Romania.|National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, Romania.
Alina D
AD
Zamfir
Orbitrap mass spectrometry; Schindler disease type I; glycopeptides; lysosomal storage diseases; α-N-acetylgalactosaminidase