Covalent structures of potato tuber lipases (patatins) and implications for vacuolar import

Karen Gjesing Welinder, Malene Jørgensen

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13 Citations (Scopus)

Abstract

Proteome data of potato (Solanum tuberosum) tuber juice and of purified potato tuber vacuoles indicated that mature patatins may perhaps lack a C-terminal propeptide. We have confirmed this by complete mass spectrometric sequencing of a number of patatin variants as well as their N-linked complex-type glycans from the starch-rich cultivar Kuras. For this cultivar full-length patatin cDNAs have also been sequenced, as the patatin locus is highly polymorphous. It is well known that patatins are located in the vacuoles of potato tubers. Furthermore, the complex glycan structures show that the path is via the Golgi apparatus. However, the vacuolar targeting signal has never been identified for this storage and defense protein, which amounts to 25-40% of tuber protein. We propose that a six-residue C-terminal propeptide, -ANKASY-COO(-) comprises this signal. The crystallographic structure of a recombinant patatin (Rydel, T. J., Williams, J. M., Krieger, E., Moshiri, F., Stallings, W. C., Brown, S. M., Pershing, J. C., Prucell, J. P., and Alibhai, M. F. (2003) Biochemistry 42, 6696-6708), which included this propeptide thus, for the first time, shows the structure of a putative ligand of the vacuolar sorting receptor and processing enzyme responsible for patatin import.
Original languageEnglish
JournalJournal of Biological Chemistry
Volume284
Issue number15
Pages (from-to)9764-9769
Number of pages5
ISSN0021-9258
DOIs
Publication statusPublished - 11 Feb 2009

Keywords

  • Patatin
  • Covaltent structure
  • Glycan structure
  • Vacuolar import

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