A soybean binding protein (BiP) homolog is temporally regulated in soybean seeds and associates detectably with normal storage proteins in vitro.
The endoplasmic reticulum (ER) luminal binding protein (BiP) is thought to be a key mediator of folding and assembly of de novo synthesized secretory proteins. We have used a maize (Zea mays L.) BiP antibady to identify its homolog in soybeans (Glycine max (L.) Merril). The accumulation of BiP in developing soybean seeds seems to be coordinated with the onset of active storage protein synthesis. We used a co-immunoprecipitation assay to detect soybean BiP:B-conglycinin interactions. Either a maize BiP antibody or a-B-conglycinin antibody co-immunoprecipitated the reciprocal protein from whole seed protein extract enzymatically depleted of adenosine 5-triphosphate (ATP), while an unrelated antibody failed to immunoprecipitate either one. The association ofBiP:B-conglycinin complexes was completely reversed by addition of ATP, a diagnostic feature of molecular chaperone-mediated interaction. However, only a very small fraction of B-conglycinin was found to be associated with BiP in whole cell protein extracts from immature seeds. These results are consistent with a transient association between BiP and B-conglycinin subunits, and suggests its involvement in the biosynthetic transport pathway of storage proteins to protein bodies.
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | Artigo de periódico biblioteca |
| Language: | English eng |
| Published: |
1997-11-14
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| Subjects: | Soybean, Seed, Protein., Biologia Molecular, Glycine Max, Proteína, Semente, Soja., molecular biology., |
| Online Access: | http://www.alice.cnptia.embrapa.br/alice/handle/doc/477302 |
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| Summary: | The endoplasmic reticulum (ER) luminal binding protein (BiP) is thought to be a key mediator of folding and assembly of de novo synthesized secretory proteins. We have used a maize (Zea mays L.) BiP antibady to identify its homolog in soybeans (Glycine max (L.) Merril). The accumulation of BiP in developing soybean seeds seems to be coordinated with the onset of active storage protein synthesis. We used a co-immunoprecipitation assay to detect soybean BiP:B-conglycinin interactions. Either a maize BiP antibody or a-B-conglycinin antibody co-immunoprecipitated the reciprocal protein from whole seed protein extract enzymatically depleted of adenosine 5-triphosphate (ATP), while an unrelated antibody failed to immunoprecipitate either one. The association ofBiP:B-conglycinin complexes was completely reversed by addition of ATP, a diagnostic feature of molecular chaperone-mediated interaction. However, only a very small fraction of B-conglycinin was found to be associated with BiP in whole cell protein extracts from immature seeds. These results are consistent with a transient association between BiP and B-conglycinin subunits, and suggests its involvement in the biosynthetic transport pathway of storage proteins to protein bodies. |
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