Structure-physicochemical property relationships at molecular levels of seed storage proteins

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Most of plant seeds except some cereals contain 7S and/or 11S globulin as major storage proteins in analogy with soybean. It is highly probable that some crops contain 7S and/or 11S globulins having useful properties different from those of soybean, since amino acid seguence identities of them with those of soybean proteins are 35-80%.1.Physicochemical properties of storage proteins of various crops :We compared physicochemical properties of 7S and/or 11S from pea, broad bean, azuki bean, kidney bean, pumpkin and bumbara bean at the same condition as that used for soybean proteins. We found that kidney bean 7S exhibits high solubility at low ionic strength and bumbara bean 11S has very low thermal stability.2.Comparison of physicochemical properties of recombinant and native 7S :Azuki bean and kidney bean 7Ss were expressed in E.coli. Comparison of physicochemical properties of the recombinant and native 7Ss indicated that carbohydrate moiety contributes to solubility at low ionic strength.3.X-ray crystallography :Recombinat soybean 11SA2Bla, pea 11S, pumpkin 11S and azuki bean 7S were subjected to crystallization. All of them except pea 11S gave crystals suitable for X-ray crystallography. We succeeded to determine their structures.4.Structure-physicochemical Property relationship :All the data we obtained in this study indicate that molecular surface electrostatic potential is a kea factor of solubility at low ionic strength.