The Role of Proteolysis in the Processing and Assembly of 11S Seed Globulins

Jung, Rudolf; Scott, M. Paul; Nam, Young‐Woo; Beaman, Todd W.; Bassüner, Ronald; Saalbach, Isolde; Müntz, Klaus; Nielsen, Niels Chr.

doi:10.1105/tpc.10.3.343

Cited by 116 publications

(75 citation statements)

References 40 publications

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“…The unprocessed precursor molecules co-migrated with 7 S pea vicilin, consistent with it being a trimer [15]. This supports earlier reports in which processing was shown to be necessary for assembly of soybean 12 S glycinin [16][17][18]. Triticin, the legumin-like globulin of wheat seeds contains the highly conserved Asn-Gly precursor proteolytic cleavage site between the acidic and basic polypeptides.…”

Section: Expression Of Legumin In Transgenic Wheatsupporting

confidence: 75%

Expression of legumin and vicilin genes in pea mutants and the production of legumin in transgenic plants

Casey¹,

Christou

Domoney

et al. 2001

Nahrung

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Pea seeds contain two major storage proteins, legumin and vicilin, in proportions that are genetically and environmentally determined. They are synthesized from at least 40 genes and at least 10 different genetic loci. Mutant alleles at loci involved in starch synthesis, which result in perturbations in starch accumulation, also affect the expression of legumin genes, thereby influencing the legumin: vicilin ratio within the total seed protein. Examples of such alleles include r (starch-branching enzyme) and rb (ADP-glucose pyrophosphorylase), both of which result in a reduction in legumin synthesis; double mutants (rrb) show a particularly severe reduction in the amount of legumin. The effects of such mutations are specific to legumins. The amounts of vicilin are unaffected by mutations at r or rb. One of the consequences of the production of legumin from many genes is structural heterogeneity that is believed to preclude the purification of homogeneous legumin for crystallization and 3D-structure determination. Expression of cloned legumin cDNA in E. coli can result in sequence homogeneity, but E. coli is unable to carry out the normal proteolytic processing of legumin precursors and consequently such material is different from that produced in pea seeds. This paper describes the high-level synthesis, processing and assembly of pea legumin in transgenic wheat seeds, leading to the spontaneous in vitro formation of paracrystalline arrays of legumin, which may be attributed to the fact that the legumin consists of a single type of subunit. Such material might be used as a source of single-sequence, processed and assembled pea legumin for structural investigation.

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Section: Expression Of Legumin In Transgenic Wheatsupporting

confidence: 75%

Expression of legumin and vicilin genes in pea mutants and the production of legumin in transgenic plants

Casey¹,

Christou

Domoney

et al. 2001

Nahrung

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“…In analogy to bVPEs of other plants ), VsPB2 may process legumin precursors by limited Asn-speci®c proteolysis during seed maturation, thus transforming trimeric prolegumin into mature hexameric legumin which is resistant against further proteolysis by bVPE (Jung et al 1998;MuÈ ntz 1998). Therefore, VsPB2 and legumin can co-exist in the protein bodies of mature seeds, and legumin has to be``activated'' before it can be attacked again by legumain-like CPRs.…”

Section: Discussionmentioning

confidence: 97%

Stored cysteine proteinases start globulin mobilization in protein bodies of embryonic axes and cotyledons during vetch ( Vicia sativa L.) seed germination

Schlereth

Standhardt

Mock

et al. 2001

Planta

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Inhibition of protein synthesis by cycloheximide during vetch seed germination, did not prevent globulin breakdown as indicated by a decrease in vicilin- and legumin-specific immunosignals on Western blots. Protein bodies isolated from embryo axes and cotyledons of dry vetch (Vicia sativa L.) seeds using a non-aqueous method were found to be free of cytoplasmic and organellar contaminations. Lysates of these purified protein bodies were capable of degrading globulins; this process was blocked by the cysteine proteinase (CPR) inhibitor iodoacetic acid. Protein bodies contained the papain-like CPR2 and CPR4, and the legumain-like CPR VsPB2. In vitro assays showed that albumin extracts from protein bodies degraded oligopeptide substrates in the PepTag-Assay and degraded the legumain substrate N-benzoyl-asparaginyl-p-nitroanilide. We conclude that, during germination, globulin mobilization is initiated by stored CPRs in protein bodies of embryonic axes as well as cotyledons, and that de-novo-formed proteolytic enzymes mainly mediate bulk degradation of stored globulin in cotyledons after germination.

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“…Deviations from the NG cleavage site usually present among the 11S subunits in angiosperms are widespread in the Taxodiaceae, Cupressaceae and Taxaceae (Häger and Fischer 1999). The asparaginyl endopeptidase that carries out post-translational modification has an absolute requirement for asparagine on the N-terminal side of the peptide bond that is cleaved, but is far-less discriminating in its choice of amino acids on the C-terminal side (Jung et al 1998). Figure 8 presents a distance-matrix diagram of the glycinin subunits that was generated using the method of Kimura (1983).…”

Section: Gy7 Encodes a New Type Of Glycinin Subunitmentioning

confidence: 99%

Genomic organization of glycinin genes in soybean

et al. 2002

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Glycinin is the predominant seed storage protein in most soybean varieties. Previously, five major genes (designated Gy1 to Gy5) encoding glycinin subunits have been described. In this report two new genes are identified and mapped: a glycinin pseudogene, gy6, and a functional gene, Gy7. Messenger RNA for the gy6 pseudogene is not detected in developing seeds. While Gy7 mRNA was present at the midmaturation stage of seed development in the soybean variety Resnik, the steady state amount of this message was at least an order of magnitude less-prevalent than the mRNA encoding each of the other five glycinin subunits. Even though the amino-acid sequence of the glycinin subunit G7 is related to the other five soybean 11S subunits, it does not fit into either the Group-1 (G1, G2, G3) or the Group-2 (G4, G5) glycinin subunit families. The Gy7 gene is tandemly linked 3' to Gy3 on Linkage Group L (chromosome 19) of the public molecular linkage map. By contrast, the gy6 gene occupies a locus downstream from Gy2 on Linkage Group N (chromosome 3) in a region that is related to the position where Gy7 is located on chromosome 19.

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The Role of Proteolysis in the Processing and Assembly of 11S Seed Globulins

Cited by 116 publications

References 40 publications

Expression of legumin and vicilin genes in pea mutants and the production of legumin in transgenic plants

Expression of legumin and vicilin genes in pea mutants and the production of legumin in transgenic plants

Stored cysteine proteinases start globulin mobilization in protein bodies of embryonic axes and cotyledons during vetch ( Vicia sativa L.) seed germination

Genomic organization of glycinin genes in soybean

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