Thaumatin, an intensely sweet-tasting plant protein, elicits a sweet taste at 50 nM. Although the sweetness remains when thaumatin is heated at 80 °C for 4h under acid conditions, it rapidly declines when heating at a pH above 6.5. To clarify the structural difference at high pH, the atomic structure of a recombinant thaumatin I at pH 8.0 was determined at a resolution of 1.0Å. Comparison to th...

We have purified a 21-kDa protein, designated as P1, from Rehmannia glutinosa to homogeneity by ammonium sulfate precipitation, anion exchange chromatography, hydrophobic interaction chromatography, and preparative native PAGE. The purified P1 had chitin degradation activity. The N-terminal amino acid sequence of P1 indicated that it is very similar to those of thaumatin and other reported thau...

Thaumatin is an intensely sweet-tasting protein that elicits sweet taste at a concentration of 50 nM, a value 100,000 times larger than that of sucrose on a molar basis. Here we attempted to produce a protein with enhanced sweetness by removing negative charges on the interacting side of thaumatin with the taste receptor. We obtained a D21N mutant which, with a threshold value 31 nM is much swe...

Substructure-solution and phasing procedures using a combination of anomalous scattering and radiation-damage-induced isomorphous differences have been investigated. The tyrosine residues in thaumatin were iodinated with N-iodosuccinimide in the crystalline form as well as prior to crystallization. Several data sets were collected from both forms and used for substructure solution and phasing u...

A phenotypic segregation of kanamycin resistance conferred by nosnptII was investigated in two groups of transgenic cucumber lines one containing the PR-2duidA-nosnptII construct and the other with the thaumatinII-nosnptII construct to the third and fifth generation, respectively. Expression of the nptII gene was more stable and predictable in the progeny of the PR-2d lines than that of thaumat...

The growth of single crystals of tetragonal HEW lysozyme and thaumatin I into glass capillaries was monitored by time lapse video-microscopy. The crystals were obtained by unidirectional transport of the precipitating agent through capillaries of internal diameter ranging from 0.2 to 1.2 mm, using the gel acupuncture technique. For crystals growing from true protein solutions, the measured aver...

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> or =9.3 in isoe...

Background Oral allergy syndrome to sapodilla plum is caused by a 21 kD allergen existing as two isoforms: an acidic thaumatin-like protein (TLP-1) and a basic thaumatin-like protein (TLP-2). The composite sequence of TLP-1 comprising the N-terminal sequence 1-7 (A-T-F-D-V/I-V-N-) and the deduced sequence 8-207 (GenBank JN624813.1) was used for this analysis. The major objective of this study w...

Results Skin prick test to mace and ginger (10%) were positive and specific IgE to Pru p3 and mace were detected. Double-blind, placebocontrolled, oral food challenge (DBPCFC) with this spice showed rhinitis in few minutes and was negative to ginger. Through electrophoresis of peach, Pru p3, mace and ginger extracts were identified and the corresponding proteins purified and characterized as al...