XVI International Botanical Congess

Glycinin is one of the major storage proteins of soybean. Three dimensional structure of its proform is required to elucidate mechanisms of processing, targeting, and accumulation in seeds. In this study, recombinant pro-A1aB1b and pro-A3B4 homotrimers were crystallized by vapor diffusion method. The structures of pro-A1aB1b and pro-A3B4 homotrimers were refined at 2.8 and 2.9 angstroms, respectively. Their polypeptides are composed of two jelly-roll barrels and two alpha-helix domains. Although the sequence identity between pro-A1aB1b and pro-A3B4 is around 40%, the core structures can be almost completely superimposed each other. Moreover, they closely resemble that of 7S globulin.