Post-translational processing of Drosophila nucleoside diphosphate kinase.
Nucleoside diphosphate kinase (NDPK) was purified from Drosophila melanogaster by a combination of anion-exchange, hydroxyapatite, and reversed-phase chromatography. The identity of the purified enzyme was confirmed by sequencing internal peptides (the N-terminus appeared to be blocked). Post-translational modifications were investigated by using protein chemical and mass spectrometric methods. Analysis by nanoelectrospray ionization-mass spectrometry revealed that the mass of the enzyme was considerably smaller than that predicted from its amino acid sequence. Although its open-reading frame predicts a 153-residue polypeptide, the mature enzyme was found to comprise 152 amino acids, being modified by proteolytic removal of the initiator Met and N-acetylation of Ala2. This explains why the observed pI of the Drosophila enzyme is more acidic than that predicted from its amino acid sequence. No additional post-translational modifications such as glycosylation or O-phosphorylation, which have been identified on homologous NDPKs from other organisms, were detected on the Drosophila enzyme.
Stenberg
Leisa M
LM
Department of Clinical Chemistry, Lund University, University Hospital, Malmö, Sweden.
Stenflo
Johan
J
Holmgren
Paul
P
Brown
Mark A
MA
D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology; D002852:Chromatography, Ion Exchange; D004331:Drosophila melanogaster / Q000201:enzymology*; D017886:Durapatite / Q000494:pharmacology; D006031:Glycosylation; D013058:Mass Spectrometry; D009701:Nucleoside-Diphosphate Kinase / Q000737:chemistry* / Q000302:isolation & purification*; D016366:Open Reading Frames; D010455:Peptides / Q000737:chemistry; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational
D001672:Biocompatible Materials; D010455:Peptides; D017886:Durapatite; D009701:Nucleoside-Diphosphate Kinase