NR AKJQ
AU Sandmeier,E.; Hunziker,P.; Kunz,B.; Sack,R.; Christen,P.
TI Spontaneous deamidation and isomerization of Asn108 in prion peptide 106-126 and in full-length prion protein
QU Biochemical and Biophysical Research Communications 1999 Aug 11; 261(3): 578-83
PT journal article
AB In prion-related encephalopathies, the cellular prion protein (PrPc) undergoes a change in conformation to become the scrapie prion protein (PrPsc) which forms infectious deposits in the brain. Conceivably, the conformational transition of PrPc to PrPsc might be linked with posttranslational alterations in the covalent structure of a fraction of the PrP molecules. We tested a synthetic peptide corresponding to residues 106-126 of human PrP for the occurrence of spontaneous chemical modifications. The only asparagine residue, Asn108, was deamidated to aspartic acid and isoaspartic acid with a half-life of about 12 days. The same posttranslational modifications were found in recombinant murine full-length protein. On aging, 0.8 mol of isoaspartyl residue per mole of protein was detected by the protein-l-isoaspartyl methyltransferase assay (t(1/2) approximately 30 days). Mass spectrometry and Edman degradation of Lys-C fragments identified Asn108 in the amino-terminal flexible part of the protein to be partially converted to aspartic acid and isoaspartic acid. A second modification was the partial isomerization of Asp226' which is only present in rodents.
MH Amino Acid Sequence; Animal; Asparagine/*chemistry; Aspartic Acid/chemistry; Chromatography, High Pressure Liquid; Hamsters; Human; Isomerism; Kinetics; Metalloendopeptidases/metabolism; Molecular Sequence Data; Peptide Fragments/*chemistry; Peptide Mapping; PrPc Proteins/chemistry; PrPsc Proteins/chemistry; Prions/*chemistry/metabolism; Protein Conformation; Protein D-Aspartate-L-Isoaspartate Methyltransferase; Protein Methyltransferases/metabolism; Spectrum Analysis, Mass; Support, Non-U.S. Gov't; Trypsin/metabolism
AD Biochemisches Institut der Universität Zürich, Winterthurerstrasse 190, Zürich, CH-8057, Switzerland.
SP englisch
PO USA