Titre
Spectroscopic and protein chemical analyses demonstrate the presence of C-mannosylated tryptophan in intact human RNase 2 and its isoforms.
Type
article
Institution
Externe
Périodique
Auteur(s)
Löffler, A.
Auteure/Auteur
Doucey, M.A.
Auteure/Auteur
Jansson, A.M.
Auteure/Auteur
Müller, D.R.
Auteure/Auteur
de Beer, T.
Auteure/Auteur
Hess, D.
Auteure/Auteur
Meldal, M.
Auteure/Auteur
Richter, W.J.
Auteure/Auteur
Vliegenthart, J.F.
Auteure/Auteur
Hofsteenge, J.
Auteure/Auteur
Liens vers les personnes
ISSN
0006-2960
Statut éditorial
Publié
Date de publication
1996
Volume
35
Numéro
37
Première page
12005
Dernière page/numéro d’article
12014
Langue
anglais
Résumé
Recently, the C-mannosylation of a specific tryptophan residue in RNase 2 from human urine has been reported [Hofsteenge, J., et al. (1994) Biochemistry 33, 13524-13530; de Beer, T., et al. (1995) Biochemistry 34, 11785-11789]. In those studies, identification of this unusual modification was accomplished by mass spectrometric and NMR spectroscopic analysis of peptide fragments. The evidence for the occurrence of C2-alpha-mannosyltryptophan [(C2-Man-)Trp] in the intact protein relied exclusively on the detection of the same phenylthiohydantoin derivatives during Edman degradation. In this paper, we have (1) excluded the possibility that (C2-Man-)Trp arose artificially under the acidic conditions previously employed for protein and peptide isolation and analysis, by maintaining the pH > 5 throughout these procedures, (2) demonstrated the occurrence of (C2-Man-)Trp in the intact protein, by NMR spectroscopy, (3) showed that (C2-Man-)Trp is not unique for RNase 2 from urine but that it is also present in the enzyme isolated from erythrocytes, and (4) found also that high-molecular mass isoforms of urinary RNase 2 are C-mannosylated. These observations firmly establish C-mannosylation as a novel way of post-translationally attaching carbohydrate to protein, in addition to the well-known N- and O-glycosylations. Furthermore, the NMR data, in combination with molecular dynamics calculations, indicate that in the native protein the mannopyranosyl residue is in a different conformation than in the glycopeptide or denatured protein, due to protein-carbohydrate interactions.
Sujets
PID Serval
serval:BIB_975D6CEF14DC
PMID
Date de création
2008-01-28T07:28:13.088Z
Date de création dans IRIS
2025-05-20T21:07:46Z