The Role of Proteolysis in the Processing and Assembly of 11S Seed GlobulinsThe Plant Cell (1998)
11S seed storage proteins are synthesized as precursors that are cleaved post-translationally in storage vacuoles by an asparaginyl endopeptidase. To study the specificity of the reaction catalyzed by this asparaginyl endopeptidase, we prepared a series of octapeptides and mutant legumin B and G4 glycinin subunits. These contained amino acid mutations in the region surrounding the cleavage site. The endopeptidase had an absolute specificity for Asn on the N-terminal side of the severed peptide bond but exhibited little specificity for amino acids on the C-terminal side. The ability of unmodified and modified subunits to assemble into hexamers after post-translational modification was evaluated. Cleavage of subunits in trimers is required for hexamer assembly in vitro. Products from a mutant gene encoding a noncleavable prolegumin subunit (LeBΔN281) accumulated as trimers in seed of transgenic tobacco, but products from the unmodified prolegumin B gene accumulated as hexamers. Therefore, the asparaginyl endopeptidase is required for hexamer assembly.
Publication DateMarch, 1998
Citation InformationRudolf Jung, Marvin Paul Scott, Young-Woo Nam, Todd W. Beaman, et al.. "The Role of Proteolysis in the Processing and Assembly of 11S Seed Globulins" The Plant Cell Vol. 10 Iss. 3 (1998) p. 343 - 357
Available at: http://works.bepress.com/paul-scott/3/