Article

Purification and characterization of a wound-inducible thaumatin-like protein from the latex of Carica papaya.

Laboratoire de Chimie Générale (CP: 206/4), Institut de Pharmacie, Université Libre de Bruxelles, Campus de la Plaine, Boulevard du Triomphe, 1050 Brussels, Belgium.
Phytochemistry (Impact Factor: 3.35). 07/2009; 70(8):970-8. DOI: 10.1016/j.phytochem.2009.05.005
Source: PubMed

ABSTRACT A 22.137 kDa protein constituent of fresh latex was isolated both from the latex of regularly damaged papaya trees and from a commercially available papain preparation. The protein was purified up to apparent homogeneity and was shown to be absent in the latex of papaya trees that had never been previously mechanically injured. This suggests that the protein belongs to pathogenesis-related protein family, as expected for several other protein constituents of papaya latex. The protein was identified as a thaumatin-like protein (class 5 of the pathogenesis-related proteins) on the basis of its partial amino acid sequence. By sequence analysis of the Carica genome, three different forms of thaumatin-like protein were identified, where the latex constituent belongs to a well-known form, allowing the molecular modeling of its spatial structure. The papaya latex thaumatin-like protein was further characterized. The protein appears to be stable in the pH interval from 2 to 10 and resistant to chemical denaturation by guanidium chloride, with a DeltaG(water)(0) of 15.2 kcal/mol and to proteolysis by the four papaya cysteine proteinases. The physiological role of this protein is discussed.

Download full-text

Full-text

Available from: Vincent Raussens, Jun 28, 2015
0 Followers
 · 
206 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Thaumatin-like proteins (TLPs) belong to the pathogenesis-related family (PR-5) of plant defense proteins. TLPs from only 32 plant genera have been identified as pollen or food allergens. IgE epitopes on allergens play a central role in food allergy by initiating cross-linking of specific IgE on basophils/mast cells. A comparative analysis of pollen- and food-allergenic TLPs is lacking. The main objective of this investigation was to study the structural and allergenicity features of sapodilla (Manilkara zapota) acidic TLP (TLP 1) by in silico methods. The allergenicity prediction of composite sequence of sapodilla TLP 1 (NCBI B3EWX8.1, G5DC91.1) was performed using FARRP, Allermatch and Evaller web tools. A homology model of the protein was generated using banana TLP template (1Z3Q) by HHPRED-MODELLER. B-cell linear epitope prediction was performed using BCpreds and BepiPred. Sapodilla TLP 1 matched significantly with allergenic TLPs from olive, kiwi, bell pepper and banana. IgE epitope prediction as performed using AlgPred indicated the presence of 2 epitopes (epitope 1: residues 36-48; epitope 2: residues 51-63), and a comprehensive analysis of all allergenic TLPs displayed up to 3 additional epitopes on other TLPs. It can be inferred from these analyses that plant allergenic TLPs generally carry 2-3 IgE epitopes. ClustalX alignments of allergenic TLPs indicate that IgE epitopes 1 and 2 are common in food allergenic TLPs, and IgE epitopes 2 and 3 are common in pollen allergenic TLPs; IgE epitope 2 overlaps with a portion of the thaumatin family signature. The secondary structural elements of TLPs vary markedly in regions 1 and 2 which harbor all the predicted IgE epitopes in all food and pollen TLPs in either of the region. Further, based on the number of IgE epitopes, food TLPs are grouped into rosid and non-rosid clades. The number and distribution of the predicted IgE epitopes among the allergenic TLPs may explain the specificity of food or pollen allergy as well as the varied degree of cross-reactivity among plant foods and/or pollens.
    Molecular Immunology 09/2013; 57(2):119-128. DOI:10.1016/j.molimm.2013.08.010 · 3.00 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Signature analysis and FSM methods are two popular methods that are used to verify the control flow of programs. Run-time fault detection in communication protocols is essential to detect faults that arise due to coding defects, memory problems and external disturbances. Run-time fault detection is essential in detecting faults that cannot be detected during the testing phase. We use a polynomial-based signature function to detect run-time faults in communication protocols
    Information Theory, 1995. Proceedings., 1995 IEEE International Symposium on; 10/1995
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A new solid acid catalyst is developed by the direct sulphonation of the ethene bond of a pure trans ethene bridged Periodic Mesoporous Organosilica. The catalytic activity of this mesoporous material is evaluated in an esterification reaction and compared with ptoluenesulphonic acid. The sulphonated ethene PMO can compete with a homogeneous catalyst and maintains its porosity.
    01/2010: pages 365-368; Elsevier Science Bv.