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Topology and phosphorylation of soybean nodulin-26, an intrinsic protein of the peribacteroid membrane
Soybean nodulin-26, a homologue of bovine eye lens major intrinsic protein (MIP-26), is an integral protein of the peribacteroid membrane in symbiotic root nodules. It comprises 271 amino acids with six potential transmembrane domains and lacks an amino-terminal signal sequence. A full-length noduli...
Formato: | Texto |
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Lenguaje: | English |
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The Rockefeller University Press
1992
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2290056/ https://www.ncbi.nlm.nih.gov/pubmed/1629242 |
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collection | PubMed |
description | Soybean nodulin-26, a homologue of bovine eye lens major intrinsic protein (MIP-26), is an integral protein of the peribacteroid membrane in symbiotic root nodules. It comprises 271 amino acids with six potential transmembrane domains and lacks an amino-terminal signal sequence. A full-length nodulin-26 cDNA and its various deletion derivatives were transcribed in vitro after linking them to bacteriophage T3 promoter. In vitro translation of these transcripts in a rabbit reticulocyte lysate, in the presence or absence of canine pancreatic microsomal membranes, suggested that nodulin-26 is cotranslationally inserted into the microsomes without a cleavable signal peptide. The first two transmembrane domains (103 amino acids) of the protein are sufficient for microsomal membrane insertion. Membrane-translocated nodulin-26 binds to Con-A and is sensitive to endoglycosidase-H treatment, suggesting that it is glycosylated. Native nodulin-26 from root nodules retains its sugar moiety as it, too, binds to Con-A. Chemical cleavage mapping at cysteine residues, a trypsin protection assay, and the Con-A binding affinity of nodulin-26 suggested that both the NH2 and COOH termini of this protein are on the cytoplasmic surface of the peribacteroid membrane, while the glycosidic residue is on the surface of the membrane facing the bacteroids. In vitro phosphorylation experiments showed that nodulin-26 is a major phosphorylated protein in the peribacteroid membrane. This phosphorylation is mediated by a Ca(2+)-dependent, calmodulin- independent protein kinase located in the peribacteriod membrane. Externally supplied acid phosphatase dephosphorylates this protein, but alkaline phosphatase does not. Based on its homology with several eukaryotic and prokaryotic channel-type membrane proteins, nodulin-26 may form a channel translocating specific molecules to the bacteroids during endosymbiosis in legume plants. |
format | Text |
id | pubmed-2290056 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1992 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-22900562008-05-01 Topology and phosphorylation of soybean nodulin-26, an intrinsic protein of the peribacteroid membrane J Cell Biol Articles Soybean nodulin-26, a homologue of bovine eye lens major intrinsic protein (MIP-26), is an integral protein of the peribacteroid membrane in symbiotic root nodules. It comprises 271 amino acids with six potential transmembrane domains and lacks an amino-terminal signal sequence. A full-length nodulin-26 cDNA and its various deletion derivatives were transcribed in vitro after linking them to bacteriophage T3 promoter. In vitro translation of these transcripts in a rabbit reticulocyte lysate, in the presence or absence of canine pancreatic microsomal membranes, suggested that nodulin-26 is cotranslationally inserted into the microsomes without a cleavable signal peptide. The first two transmembrane domains (103 amino acids) of the protein are sufficient for microsomal membrane insertion. Membrane-translocated nodulin-26 binds to Con-A and is sensitive to endoglycosidase-H treatment, suggesting that it is glycosylated. Native nodulin-26 from root nodules retains its sugar moiety as it, too, binds to Con-A. Chemical cleavage mapping at cysteine residues, a trypsin protection assay, and the Con-A binding affinity of nodulin-26 suggested that both the NH2 and COOH termini of this protein are on the cytoplasmic surface of the peribacteroid membrane, while the glycosidic residue is on the surface of the membrane facing the bacteroids. In vitro phosphorylation experiments showed that nodulin-26 is a major phosphorylated protein in the peribacteroid membrane. This phosphorylation is mediated by a Ca(2+)-dependent, calmodulin- independent protein kinase located in the peribacteriod membrane. Externally supplied acid phosphatase dephosphorylates this protein, but alkaline phosphatase does not. Based on its homology with several eukaryotic and prokaryotic channel-type membrane proteins, nodulin-26 may form a channel translocating specific molecules to the bacteroids during endosymbiosis in legume plants. The Rockefeller University Press 1992-07-02 /pmc/articles/PMC2290056/ /pubmed/1629242 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/). |
spellingShingle | Articles Topology and phosphorylation of soybean nodulin-26, an intrinsic protein of the peribacteroid membrane |
title | Topology and phosphorylation of soybean nodulin-26, an intrinsic protein of the peribacteroid membrane |
title_full | Topology and phosphorylation of soybean nodulin-26, an intrinsic protein of the peribacteroid membrane |
title_fullStr | Topology and phosphorylation of soybean nodulin-26, an intrinsic protein of the peribacteroid membrane |
title_full_unstemmed | Topology and phosphorylation of soybean nodulin-26, an intrinsic protein of the peribacteroid membrane |
title_short | Topology and phosphorylation of soybean nodulin-26, an intrinsic protein of the peribacteroid membrane |
title_sort | topology and phosphorylation of soybean nodulin-26, an intrinsic protein of the peribacteroid membrane |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2290056/ https://www.ncbi.nlm.nih.gov/pubmed/1629242 |