title: Patatins, Kunitz protease inhibitors and other major proteins in tuber of potato cv. Kuras.
abstract: The major potato tuber proteins of the Kuras cultivar, which is the dominant cultivar used in Northern Europe for industrial starch production, were analysed using 1D and 2D gel electrophoresis. The electrophoretic patterns varied significantly depending on the method of preparation and the potato variant (Solanum tuberosum). Proteins were characterized using MS and scored against potato protein databases, derived from both 'Kuras only' and 'all potato' expressed sequence tags (EST) and full-length cDNAs. Despite the existence of approximately 180 000 ESTs, the currently available potato sequence data showed a severe under-representation of genes or long transcripts encoding proteins > 50 kDa (3.5% of all) compared with the complete proteome of Arabidopsis thaliana (33% of all). We found that patatin and Kunitz protease inhibitor (KPI) variants are extraordinarily dominant in Kuras tuber and, most significantly, that their amino acid sequences are specific to Kuras. Other proteins identified include annexin, glyoxalase I, enolase and two lipoxygenases, the sequences of which are highly conserved among potato variants. Known S. tuberosum patatins cluster into three clades all represented in Kuras. S. tuberosum KPIs cluster into more diverse clades of which five were found in Kuras tuber, including a novel clade, KPI K, found to date only in Kuras. Furthermore, protein abundance was contrasted with the levels of corresponding gene transcripts found in our previous EST and LongSAGE studies of Kuras tuber.
authors.affiliation: Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Denmark.
authors.forename: Guy
authors.initials: G
authors.lastname: Bauw
authors.forename: Heidi V
authors.initials: HV
authors.lastname: Nielsen
authors.forename: Jeppe
authors.initials: J
authors.lastname: Emmersen
authors.forename: Kåre L
authors.initials: KL
authors.lastname: Nielsen
authors.forename: Malene
authors.initials: M
authors.lastname: Jørgensen
authors.forename: Karen G
authors.initials: KG
authors.lastname: Welinder
mesh_terms: D000595:Amino Acid Sequence; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D015180:Electrophoresis, Gel, Two-Dimensional; D020224:Expressed Sequence Tags; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D011198:Solanum tuberosum / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: C053865:Kunitz-type protease inhibitor, plant; D010455:Peptides; D010940:Plant Proteins; C043222:patatin protein, Solanum tuberosum; D002265:Carboxylic Ester Hydrolases