Identification and characterization of beta-lathyrin, an abundant glycoprotein of grass pea (Lathyrus sativus L.), as a potential allergen

Authors: XU, QUANLE - Northwest Agriculture And Forestry University; SONG, BO - Northwest Agriculture And Forestry University; LIU, FENGJUAN - Northwest Agricultural University; SONG, YAOYAO - Northwest Agriculture And Forestry University; CHEN, PENG - Northwest Agriculture And Forestry University; LIU, SHANSHAN - Northwest Agricultural University; Krishnan, Hari

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/27/2018
Publication Date: 7/27/2018
Citation: Xu, Q., Song, B., Liu, F., Song, Y., Chen, P., Liu, S., Krishnan, H.B. 2018. Identification and characterization of beta-lathyrin, an abundant glycoprotein of grass pea (Lathyrus sativus L.), as a potential allergen. Journal of Agricultural and Food Chemistry. 66(32):8496-8503. https://doi.org/10.1021/acs.jafc.8b02314.
DOI: https://doi.org/10.1021/acs.jafc.8b02314

Interpretive Summary: Grass pea is an important legume that can withstand harsh environmental conditions including drought and flooding. On account of these characteristics grass pea is often grown in drought-prone areas. Like soybean, grass pea seeds are relatively rich in protein and can serve as inexpensive source of highly nutritious and well-balanced source of human dietary protein. The seed proteins of soybean and grass pea are similar. In this study, we have examined for the presence of allergens in grass pea seeds. We have identified an abundant protein (beta-lathyrin) from grass pea as a major allergen. Grass pea beta-lathyrin revealed extensive sequence homology to several known allergens including those from peanut and soybean. Results from this study shows that these legume allergens are highly conserved and exhibit very similar properties in inducing immune responses. The information obtained from this study will help plant breeders to develop legumes that are devoid of major allergens so that we can improve the overall quality of legume seed proteins. Superior quality legume proteins can be utilized to meet the nutritional requirements of the multitude of malnourished people around the world.

Technical Abstract: Grass pea, a protein-rich, high-yielding and drought-resistant legume, is utilized as food and livestock feed in several tropical and subtropical regions of the world. The abundant seed proteins of grass pea are salt-soluble globulins, which can be separated into vicilins and legumins. In many other legumes, the members of vicilin seed proteins have been identified as major allergens. However, very little information is available on the allergens of grass pea. In this study, we have identified an abundant 47 kDa protein from grass pea which is recognized by IgE antibodies from sera drawn from several peanut-allergic patients. The IgE-binding 47 kDa protein was partially purified by affinity chromatography on a Con-A sepharose column. MALDI-TOF mass spectrometry analysis of the 47 kDa grass pea protein revealed sequence homology to 47 kDa vicilin from pea and Len C 1 from lentil. Interestingly the grass pea vicilin was found to susceptible to pepsin digestion in vitro. We have also isolated a cDNA clone encoding the grass pea 47 kDa vicilin (beta-lathyrin) and the deduced amino acid sequence revealed extensive homology to several known allergens including those from peanut and soybean. A homology model structure of the grass pea beta-lathyrin, generated using the X-ray crystal structure of the soybean beta-conglycinin beta-subunit as a template, revealed potential IgE-binding epitopes located on the surface of the molecule. The similarity in the three-dimensional structure and the conservation of the antigenic epitopes on the molecular surface of vicilin allergens explains for the IgE-binding cross-reactivity.