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| Research the Allergenicity of Cowpea Trypsin Inhibitor Using Bioinformatic Analysis |
| ,Na Sun,Cui-yan WANG,Lu SUN,Hui-Lian CHE |
| China Agricultural University |
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Abstract With the application of cowpea trypsin inhibitor gene(CpTI) in crops such as cotton and rice, distribution of CpTI in human food is increasingly widespread. As a foreign protein, the allergenicity of CpTI has aroused people’s concern. Recent years some web-based tools that integrate with databases of allergenic proteins could be used to improve our ability to predict allergenicity based on structural analysis. In this study, bioinformatic analysis methods were used to evaluate the potential allergenicity of CpTI and the outcome was then compared with results of other methods aimed to conform its potential allergenicity more clearly. Allergenonline, structure database of allergic protein(SDAP), DNAStar software and Kolaskar-Tongaonkar online server were used to compare and analyze CpTI’s allergenicity and immunogenicity on the basis of analyzing its physical and chemical properties. The Allergenonline and SDAP database were used to predict the similarity of amino acid of CpTI with known allergens collected in the databases. The primary comparison methods included the identification of similar sequence that hold more than 35% in a known 80 amino acid sequence, and the existence of continue 6 or 8 amino acid that same as that in CpTI in known allergic sequences. Besides, the physical and chemical properties containing isoelectric point, stability coefficient, coefficient of fat, existence of signal peptide were analyzed using online servers of ProtPara (http://web.expasy.org/protparam/), SignakIP4. (http://www.cbs.dtu.dk/services/SignalP/) and TMHMM (http://www.cbs.dtu.dk/services/TMH MM-2.0/). The result of properties analysis showed that CpTI’s theoretical isoelectric point was 4.96, unstable and fat coefficient were 95.57 and 33.68 respectively, and did not contain signal peptid. So we conclude that the CpTI is a protein of unstable and hydrophobi. Bioinformatics analysis showed that CpTI’s antigen epitope area of amino acid was 76~80, which was less than 6 amino acids and almost could not form the antigenic determinant. Besides, the highest identity match of CpTI with known food allergens was 18.85% over any segment of 80 continuous amino acids and that there was no peptide matches of 6 or 8 continuous amino acids to known allergens in Allergenonline and SDAP datebases. The DNAStar and Kolaskar-Tongaonkar online server can be used to predict protein’s immunogenity and the allergenonline, SDAP can analyze potential allergeinicity. The obtained results using analyze method in this research did not appear any significant allergen epitope and potential allergenicity in CpTI. Combining with previous researches, it is considered that the CpTI is a non- or hypo-allergenic protein. This research may provide scientific reference for predicting potential allergenicity of de novo protein using bioinformatic analysis tools.
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Received: 06 August 2013
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Corresponding Authors:
Hui-Lian CHE
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