TLXI, a novel type of xylanase inhibitor from wheat (Triticum aestivum) belonging to the thaumatin family
| Autor: | Hans Goesaert, Christophe M. Courtin, Jan A. Delcour, Kristof Brijs, Kurt Gebruers, Paul Proost, Steven Van Campenhout, Johnny Beaugrand, Sigrid Rombouts, Guido Volckaert, Ellen Fierens |
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| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Předmět: |
Glycosylation
Time Factors thaumatin-like protein (tlp) slow tight binding Trypsin inhibitor Molecular Sequence Data endoxylanase inhibitors Biology aspartic protease inhibitor Biochemistry Mass Spectrometry Pichia pastoris plant defense Glycoside hydrolase family 10 Glycoside hydrolase family 11 Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase Amino Acid Sequence Cloning Molecular Enzyme Inhibitors thaumatin-like xylanase inhibitor (tlxi) different cereals Molecular Biology Peptide sequence Triticum Plant Proteins Mesylates Endo-1 4-beta Xylanases wheat (triticum aestivum) Base Sequence Molecular mass food and beverages heterologous expression xip-i barley structural basis Cell Biology biology.organism_classification tight-binding-inhibition proteins Kinetics taxi-type Thaumatin Xylanase xylanase inhibitor Electrophoresis Polyacrylamide Gel Xylans Research Article |
| Popis: | Wheat (Triticum aestivum) contains a previously unknown type of xylanase (EC 3.2.1.8) inhibitor, which is described in the present paper for the first time. Based on its > 60 % similarity to TLPs (thaumatin-like proteins) and the fact that it contains the Prosite PS00316 thaumatin family signature, it is referred to as TLXI (thaumatin-like xylanase inhibitor). TLXI is a basic (pI >=, 9.3 in isoelectric focusing) protein with a molecular mass of approx. 18 kDa (determined by SDS/PAGE) and it occurs in wheat with varying extents of glycosylation. The TLXI gene sequence encodes a 26-amino-acid signal sequence followed by a 151-amino-acid mature protein with a calculated molecular mass of 15.6 kDa and pl of 8.38. The mature TLXI protein was expressed successfully in Pichia pastoris, resulting in a 21 kDa (determined by SDS/PAGE) recombinant protein (rTLXI). Polyclonal antibodies raised against TLXI purified from wheat react with epitopes of rTLXI as well as with those of thaumatin, demonstrating high structural similarity between these three proteins. TLXI has a unique inhibition specificity. It is a noncompetitive inhibitor of a number of glycoside hydrolase family 11 xylanases, but it is inactive towards glycoside hydrolase family 10 xylanases, Progress curves show that TLXI is a slow tight-binding inhibitor, with a K-i of approx. 60 nM. Except for zeamatin, an alpha-amylase/trypsin inhibitor from maize (Zea mays), no other enzyme inhibitor is currently known among the TLPs. TLXI thus represents a novel type of inhibitor within this group of proteins. ispartof: Biochemical Journal vol:403 issue:3 pages:583-591 ispartof: location:England status: published |
| Databáze: | OpenAIRE |
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