Source:http://linkedlifedata.com/resource/pubmed/id/21389620
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
3
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| pubmed:dateCreated |
2011-4-6
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| pubmed:abstractText |
Mammalian thioredoxin reductases (TrxRs) contain selenium as selenocysteine (Sec) in the C-terminal redox center -Gly-Cys-Sec-Gly-OH to reduce Trx and other substrates; a Sec-to-Cys substitution in mammalian TrxR yields an almost inactive enzyme. The corresponding tetrapeptide sequence in Drosophila melanogaster TrxR (Dm-TrxR), -Ser-Cys-Cys-Ser-OH, endows the orthologous enzyme with a catalytic competence similar to mammalian selenoenzymes, but implementation of the Ser-containing tetrapeptide sequence SCCS into the mammalian enzyme does not restore the activity of the Sec-to-Cys mutant form (turnover number <2/min). MOPAC calculation suggested that the C-terminal hexapeptide Pro-Ala-Ser-Cys-Cys-Ser-OH functions as a redox center that alleviates the necessity for selenium in Dm-TrxR, and a mutant form of human lung TrxR that mimics this hexapeptide sequence showed improved catalytic turnover (17.4/min for DTNB and 13.2/min for E. coli trx) compared to the Sec-to-Cys mutant. MOPAC calculation also suggested that the dominant form of the Pro-containing hexapeptide is a C+ conformation, which perhaps has a catalytic advantage in facile reduction of the intramolecular disulfide bond between Cys497 and Cys498 by the N-terminal redox center in the neighboring subunit.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Cysteine,
http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Selenium,
http://linkedlifedata.com/resource/pubmed/chemical/Selenocysteine,
http://linkedlifedata.com/resource/pubmed/chemical/Thioredoxin-Disulfide Reductase
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| pubmed:status |
MEDLINE
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| pubmed:issn |
1347-6947
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| pubmed:author | |
| pubmed:issnType |
Electronic
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| pubmed:volume |
75
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
516-21
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| pubmed:meshHeading |
pubmed-meshheading:21389620-Amino Acid Motifs,
pubmed-meshheading:21389620-Amino Acid Sequence,
pubmed-meshheading:21389620-Animals,
pubmed-meshheading:21389620-Base Sequence,
pubmed-meshheading:21389620-Binding Sites,
pubmed-meshheading:21389620-Biocatalysis,
pubmed-meshheading:21389620-Cysteine,
pubmed-meshheading:21389620-Drosophila melanogaster,
pubmed-meshheading:21389620-Escherichia coli,
pubmed-meshheading:21389620-Humans,
pubmed-meshheading:21389620-Kinetics,
pubmed-meshheading:21389620-Lung,
pubmed-meshheading:21389620-Models, Molecular,
pubmed-meshheading:21389620-Molecular Sequence Data,
pubmed-meshheading:21389620-Mutation,
pubmed-meshheading:21389620-Oxidation-Reduction,
pubmed-meshheading:21389620-Recombinant Proteins,
pubmed-meshheading:21389620-Selenium,
pubmed-meshheading:21389620-Selenocysteine,
pubmed-meshheading:21389620-Sequence Homology, Amino Acid,
pubmed-meshheading:21389620-Thioredoxin-Disulfide Reductase
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| pubmed:year |
2011
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| pubmed:articleTitle |
Identification and conformer analysis of a novel redox-active motif, Pro-Ala-Ser-Cys-Cys-Ser, in Drosophila thioredoxin reductase by semiempirical molecular orbital calculation.
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| pubmed:affiliation |
Department of Bioresources Chemistry, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan.
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| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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