Source:http://linkedlifedata.com/resource/pubmed/id/10320345
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
19
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pubmed:dateCreated |
1999-6-7
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pubmed:abstractText |
A key step in fungal biosynthesis of lysine, enzymatic reduction of alpha-aminoadipate at C6 to the semialdehyde, requires two gene products in Saccharomyces cerevisiae, Lys2 and Lys5. Here, we show that the 31-kDa Lys5 is a specific posttranslational modification catalyst, using coenzyme A (CoASH) as a cosubstrate to phosphopantetheinylate Ser880 of the 155-kDa Lys2 and activate it for catalysis. Lys2 was subcloned from S. cerevisiae and expressed in and purified from Escherichia coli as a full-length 155-kDa enzyme, as a 105-kDa adenylation/peptidyl carrier protein (A/PCP) fragment (residues 1-924), and as a 14-kDa PCP fragment (residues 809-924). The apo-PCP fragment was covalently modified to phosphopantetheinylated holo-PCP by pure Lys5 and CoASH with a Km of 1 microM and kcat of 3 min-1 for both the PCP and CoASH substrates. The adenylation domain of the A/PCP fragment activated S-carboxymethyl-L-cysteine (kcat/Km = 840 mM-1 min-1) at 16% the efficiency of L-alpha-aminoadipate in [32P]PPi/ATP exchange assays. The holo form of the A/PCP 105-kDa fragment of Lys2 covalently aminoacylated itself with [35S]S-carboxymethyl-L-cysteine. Addition of NADPH discharged the covalent acyl-S-PCP Lys2, consistent with a reductive cleavage of the acyl-S-enzyme intermediate. These results identify the Lys5/Lys2 pair as a two-component system in which Lys5 covalently primes Lys2, allowing alpha-aminoadipate reductase activity by holo-Lys2 with catalytic cycles of autoaminoacylation and reductive cleavage. This is a novel mechanism for a fungal enzyme essential for amino acid metabolism.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/2-Aminoadipic Acid,
http://linkedlifedata.com/resource/pubmed/chemical/Acyl Carrier Protein,
http://linkedlifedata.com/resource/pubmed/chemical/Aldehyde Oxidoreductases,
http://linkedlifedata.com/resource/pubmed/chemical/Carbocysteine,
http://linkedlifedata.com/resource/pubmed/chemical/L-Aminoadipate-Semialdehyde...,
http://linkedlifedata.com/resource/pubmed/chemical/Lysine,
http://linkedlifedata.com/resource/pubmed/chemical/NADP,
http://linkedlifedata.com/resource/pubmed/chemical/Sulfur Radioisotopes,
http://linkedlifedata.com/resource/pubmed/chemical/allysine
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pubmed:status |
MEDLINE
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pubmed:month |
May
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pubmed:issn |
0006-2960
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
11
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pubmed:volume |
38
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
6171-7
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:10320345-2-Aminoadipic Acid,
pubmed-meshheading:10320345-Acyl Carrier Protein,
pubmed-meshheading:10320345-Aldehyde Oxidoreductases,
pubmed-meshheading:10320345-Carbocysteine,
pubmed-meshheading:10320345-Escherichia coli,
pubmed-meshheading:10320345-L-Aminoadipate-Semialdehyde Dehydrogenase,
pubmed-meshheading:10320345-Lysine,
pubmed-meshheading:10320345-NADP,
pubmed-meshheading:10320345-Protein Processing, Post-Translational,
pubmed-meshheading:10320345-Saccharomyces cerevisiae,
pubmed-meshheading:10320345-Sulfur Radioisotopes
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pubmed:year |
1999
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pubmed:articleTitle |
Lysine biosynthesis in Saccharomyces cerevisiae: mechanism of alpha-aminoadipate reductase (Lys2) involves posttranslational phosphopantetheinylation by Lys5.
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pubmed:affiliation |
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.,
Research Support, Non-U.S. Gov't
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