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Structures of the glycosyl-phosphatidylinositol anchors of porcine and human renal membrane dipeptidase. Comprehensive structural studies on the porcine anchor and interspecies comparison of the glycan core structures.
Brewis, I A; Ferguson, M A; Mehlert, A; Turner, A J; Hooper, N M.
Afiliação
  • Brewis IA; Department of Biochemistry and Molecular Biology, University of Leeds, United Kingdom.
J Biol Chem ; 270(39): 22946-56, 1995 Sep 29.
Article em En | MEDLINE | ID: mdl-7559431
The glycan core structures of the glycosyl-phosphatidylinositol (GPI) anchors on porcine and human renal membrane dipeptidase (EC 3.4.13.19) were determined following deamination and reduction by a combination of liquid chromatography, exoglycosidase digestions, and methylation analysis. The glycan core was found to exhibit microheterogeneity with three structures observed for the porcine GPI anchor: Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcN (29% of the total population), Man alpha 1-2Man alpha 1-6(GalNAc beta 1-4)Man alpha 1-4GlcN (33%), and Man alpha 1-2Man alpha 1-6(Gal beta 1-3GalNAc beta 1-4)Man alpha 1-4GlcN (38%). The same glycan core structures were also found in the human anchor but in slightly different proportions (25, 52, and 17%, respectively). Additionally, a small amount (6%) of the second structure with an extra mannose alpha (1-2)-linked to the non-reducing terminal mannose was also observed in the human membrane dipeptidase GPI anchor. A small proportion (maximally 9%) of the porcine GPI anchor structures was found to contain sialic acid, probably linked to the GalNAc residue. The porcine GPI anchor was found to contain 2.5 mol of ethanolamine/mol of anchor. Negative-ion electrospray-mass spectrometry revealed the presence of exclusively diacyl-phosphatidylinositol (predominantly distearoyl-phosphatidylinositol with a minor amount of stearoyl-palmitoyl-phosphatidylinositol) in the porcine membrane dipeptidase anchor. Porcine membrane dipeptidase was digested with trypsin and the C-terminal peptide attached to the GPI anchor isolated by removal of the other tryptic peptides on anhydrotrypsin-Sepharose. The sequence of this peptide was determined as Thr-Asn-Tyr-Gly-Tyr-Ser, thereby identifying the site of attachment of the GPI anchor as Ser368. This work represents a comprehensive study of the GPI anchor structure of porcine membrane dipeptidase and the first interspecies comparison of mammalian GPI anchor structures on the same protein.
Assuntos
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Base de dados: MEDLINE Assunto principal: Polissacarídeos / Glicosilfosfatidilinositóis / Dipeptidases / Rim Limite: Animals / Humans Idioma: En Revista: J Biol Chem Ano de publicação: 1995 Tipo de documento: Article País de afiliação: Reino Unido
Buscar no Google
Base de dados: MEDLINE Assunto principal: Polissacarídeos / Glicosilfosfatidilinositóis / Dipeptidases / Rim Limite: Animals / Humans Idioma: En Revista: J Biol Chem Ano de publicação: 1995 Tipo de documento: Article País de afiliação: Reino Unido