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Title: Isolation and characterization of Korean pine (Pinus koraiensis)convicilin

item JIN, TENGCHUAN - Illinois Institute Of Technology
item WANG, YANG - Illinois Institute Of Technology
item CHEN, YU-WEI - Illinois Institute Of Technology
item ALBILLOS, SYLVIA - Illinois Institute Of Technology
item KOTHARY, MAHENDRA - Food And Drug Administration(FDA)
item FU, TONG-JEN - Food And Drug Administration(FDA)
item TANKERSLEY, BOYCE - Chicago Botanical Garden
item McHugh, Tara
item Zhang, Yuzhu

Submitted to: Plant Physiology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2014
Publication Date: 3/27/2014
Citation: Jin, T., Wang, Y., Chen, Y., Albillos, S.M., Kothary, M.H., Fu, T., Tankersley, B., Mchugh, T.H., Zhang, Y. 2014. Isolation and characterization of Korean pine (Pinus koraiensis)convicilin. Plant Physiology and Biochemistry. 80:97-104. DOI: 10.1016/j.plaphy.2014.03.019.

Interpretive Summary: This study reported the isolation and characterization of a buffer extractable protein from the seeds of Korean pine. With N-terminal amino acid sequencing and database mining, it was found that the sequence of this protein is homologous to a previously uncharacterized gene in the Loblolly pine EST. The coding sequence of convicilin from Korean pine was then isolated. Compared with the biochemical properties of vicilin, convicilin has similar secondary structure components and also appears to be homotrimer in its native state. The thermal and chemical stabilities of these two proteins, however, are quite different. Pine nut allergy cases have been reported, but no pine nut allergen has been identified. Whether pine vicilin/convicilin is an allergen needs to be determined as they belong to a protein family that includes many known allergens in other foods. Availability of purified pine nut storage proteins will facilitate the identification and characterization of pine nut allergens and the study of pine nut allergies.

Technical Abstract: A vicilin-like globulin seed storage protein, termed convicilin, was isolated for the first time from Korean pine (Pinus koraiensis) by a combination of anion exchange, hydrophobic interaction, and gel filtration chromatography. The protein is less abundant than vicilin in low-salt extracts of mature Korean pine seeds. SDS-PAGE analysis revealed that convicilin was post-translationally processed. The N-terminal peptide sequences of its components were determined. These peptides could be mapped to a protein translated from an embryo abundant transcript. Similar to vicilin, native convicilin appeared to be homotrimeric. Circular dichroism (CD) and differential scanning calorimetry (DSC) analyses revealed that this protein is less resistant to thermal treatment than pine vicilin. Its transition temperature was 75.57 degrees C compared with 84.13 degrees C for vicilin. The urea induced folding-unfolding equilibrium of pine convicilin monitored by intrinsic fluorescence could be interpreted in terms of a two-state model, with a Cm of 4.41±0.15 M.