The biology of plant proteins

Studies on the chemical composition of fruits and seeds of Pseudocydonia sinensis (Thouin) C.K. Schneid

Pseudocydonia sinensis (Thouin) C. K. Schneid. less known plant species in the Ukraine conditions, but the fruits were widely used in traditional Chinese medicine for the treatment of asthma, colds, sore throat, mastitis, rheumatoid arthritis, and tuberculosis. The content of protein, ash, and lipids in the seeds was found to be greater than in the pulp and peel. Monosaccharide analysis of neutral carbohydrate part showed the presence of two main sugars fructose and sucrose in the seeds, pulp, and peel. There is a higher beta-carotene content in the rind of the fruit than in the seeds and pulp. The total amount of fatty acids varied from sample to sample and contained mainly oleic acid, palmitic acid, linolenic acid, and linoleic acid. Linoleic acid in the seeds was 48.02% of total fatty acids, slightly less in the rind 42.70%. Palmitic acid, oleic acid, and linoleic acid in the pulp samples were 45.38, 21.32, and 14.93%, respectively. The total amount of amino acids found in the seeds was 105.0 g.kg-1 DM, including total essential amino acids (32.70 g.kg-1 DM). Glutamic acid was found in seeds to be the dominant free amino acid followed by aspartic acid and arginine in the seed. In our study, the antioxidant activity carried out by the DPPH method and measured by molybdenum reducing antioxidant power of peel, pulp and seeds were 9.41, 7.08, 6.21, and 158.81, 92.83, 78.58 mg TEAC.g-1 DM, respectively. Micro and macronutrients and amino acids predominated in the seeds, total fatty acids predominated in the pulp. The highest content of bioactive compounds (total polyphenols, flavonoid, and phenolic acid) and antioxidant activity was found in the peel. P. sinensis can be considered as a nourishing fruit with a copious potential with health-promoting roles and medicinal properties.

Modeling to Understand Plant Protein Structure-Function Relationships-Implications for Seed Storage Proteins

Proteins are among the most important molecules on Earth. Their structure and aggregation behavior are key to their functionality in living organisms and in protein-rich products. Innovations, such as increased computer size and power, together with novel simulation tools have improved our understanding of protein structure-function relationships. This review focuses on various proteins present in plants and modeling tools that can be applied to better understand protein structures and their relationship to functionality, with particular emphasis on plant storage proteins. Modeling of plant proteins is increasing, but less than 9% of deposits in the Research Collaboratory for Structural Bioinformatics Protein Data Bank come from plant proteins. Although, similar tools are applied as in other proteins, modeling of plant proteins is lagging behind and innovative methods are rarely used. Molecular dynamics and molecular docking are commonly used to evaluate differences in forms or mutants, and the impact on functionality. Modeling tools have also been used to describe the photosynthetic machinery and its electron transfer reactions. Storage proteins, especially in large and intrinsically disordered prolamins and glutelins, have been significantly less well-described using modeling. These proteins aggregate during processing and form large polymers that correlate with functionality. The resulting structure-function relationships are important for processed storage proteins, so modeling and simulation studies, using up-to-date models, algorithms, and computer tools are essential for obtaining a better understanding of these relationships.

Allergenicity assessment of osmotin, a pathogenesis-related protein, used for transgenic crops

Genetic engineering can enhance abiotic stress tolerance of plants, thereby increasing productivity. The present study investigates allergenicity of osmotin protein used for developing transgenic crops. Bioinformatic analysis of osmotin was performed using SDAP and Farrp allergen databases. Osmotin was cloned in pET22b+ vector, purified to homogeneity, and analyzed for digestibility, heat stability, and IgE binding using atopic patients' sera. Osmotin showed 40-92% and 48-75% homology with allergens in SDAP and Farrp databases, respectively. These cross-reactive allergens were from apple, tomato, peach, capsicum, kiwi fruit, and cypress. Osmotin was resistant to pepsin digestion and heat treatment at 90 °C for 1 h. Osmotin protein showed dose-dependent inhibition with pooled patients' sera. It showed significant IgE binding with 22 of 117 patients' sera who were sensitized to tomato and apple, thus indicating cross-reactivity among tomato, apple, and osmotin allergens. In conclusion, osmotin was identified as a potential allergen and showed cross-reactivity with tomato and apple allergens.