Source:http://linkedlifedata.com/resource/pubmed/id/16593759
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| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
18
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| pubmed:dateCreated |
2010-6-30
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| pubmed:abstractText |
5-enolPyruvylshikimate-3-phosphate synthase (EPSP synthase; 3-phosphoshikimate 1-carboxyvinyl-transferase; EC 2.5.1.19) is a chloroplast-localized enzyme of the shikimate pathway in plants. This enzyme is the target for the nonselective herbicide glyphosate (N-phosphonomethylglycine). We have previously isolated a full-length cDNA clone of EPSP synthase from Petunia hybrida. DNA sequence analysis suggested that the enzyme is synthesized as a cytosolic precursor (pre-EPSP synthase) with an amino-terminal transit peptide. Based on the known amino terminus of the mature enzyme, and the 5' open reading frame of the cDNA, the transit peptide of pre-EPSP synthase would be maximally 72 amino acids long. To confirm this prediction and to assay directly for translocation of pre-EPSP synthase into chloroplasts in vitro, we cloned the full-length cDNA into an SP6 transcription system to produce large amounts of mRNA for in vitro translation. The translation products, when analyzed by NaDodSO(4)/PAGE autoradiography, indicate a relative molecular mass for pre-EPSP synthase of approximately 55 kDa. Uptake studies with intact chloroplasts, in vitro, indicate that pre-EPSP synthase was rapidly taken up into chloroplasts and proteolytically cleaved to the mature approximately 48-kDa enzyme. The transit peptide was shown to be essential for import of the precursor enzyme into the chloroplast. To our knowledge, post-translational import into chloroplasts of a precursor enzyme involved in amino acid biosynthesis has not been reported previously. Furthermore, enzymatic analysis of translation products indicates that pre-EPSP synthase is catalytically active and has a similar sensitivity to the herbicide glyphosate as the mature enzyme. To our knowledge, pre-EPSP synthase represents the only example of a catalytically competent chloroplast-precursor enzyme.
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| pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-15918225,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-16654194,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-16663362,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-16663815,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-17794571,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-2998781,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-3514209,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-3943133,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-3969146,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-521455,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-5432063,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-6207484,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-6318829,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-6430703,
http://linkedlifedata.com/resource/pubmed/commentcorrection/16593759-7396959
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:status |
PubMed-not-MEDLINE
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| pubmed:month |
Sep
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| pubmed:issn |
0027-8424
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:volume |
83
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
6873-7
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| pubmed:dateRevised |
2010-9-14
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| pubmed:year |
1986
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| pubmed:articleTitle |
Translocation of the precursor of 5-enolpyruvylshikimate-3-phosphate synthase into chloroplasts of higher plants in vitro.
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| pubmed:affiliation |
Monsanto Company, Plant Molecular Biology Group, Division of Biological Sciences, 700 Chesterfield Village Parkway, St. Louis, MO 63198.
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| pubmed:publicationType |
Journal Article
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