| pubmed-article:17661444 | rdf:type | pubmed:Citation | lld:pubmed |
| pubmed-article:17661444 | lifeskim:mentions | umls-concept:C0039941 | lld:lifeskim |
| pubmed-article:17661444 | lifeskim:mentions | umls-concept:C1261322 | lld:lifeskim |
| pubmed-article:17661444 | lifeskim:mentions | umls-concept:C0030012 | lld:lifeskim |
| pubmed-article:17661444 | lifeskim:mentions | umls-concept:C0033629 | lld:lifeskim |
| pubmed-article:17661444 | lifeskim:mentions | umls-concept:C0205099 | lld:lifeskim |
| pubmed-article:17661444 | lifeskim:mentions | umls-concept:C1707271 | lld:lifeskim |
| pubmed-article:17661444 | pubmed:issue | 33 | lld:pubmed |
| pubmed-article:17661444 | pubmed:dateCreated | 2007-8-16 | lld:pubmed |
| pubmed-article:17661444 | pubmed:abstractText | High-molecular weight thioredoxin reductases (TRs) catalyze the reduction of the redox-active disulfide bond of thioredoxin, but an important difference in the TR family is the sequence of the C-terminal redox-active tetrapeptide that interacts directly with thioredoxin, especially the presence or absence of a selenocysteine (Sec) residue in this tetrapeptide. In this study, we have employed protein engineering techniques to investigate the C-terminal redox-active tetrapeptides of three different TRs: mouse mitochondrial TR (mTR3), Drosophila melanogaster TR (DmTR), and the mitochondrial TR from Caenorhabditis elegans (CeTR2), which have C-terminal tetrapeptide sequences of Gly-Cys-Sec-Gly, Ser-Cys-Cys-Ser, and Gly-Cys-Cys-Gly, respectively. Three different types of mutations and chemical modifications were performed in this study: insertion of alanine residues between the cysteine residues of the Cys-Cys or Cys-Sec dyads, modification of the charge at the C-terminus, and altering the position of the Sec residue in the mammalian enzyme. The results show that mTR3 is quite accommodating to insertion of alanine residues into the Cys-Sec dyad, with only a 4-6-fold drop in catalytic activity. In contrast, the activity of both DmTR and CeTR2 was reduced 100-300-fold when alanine residues were inserted into the Cys-Cys dyad. We have tested the importance of a salt bridge between the C-terminus and a basic residue that was proposed for orienting the Cys-Sec dyad of mTR3 for proper catalytic position by changing the C-terminal carboxylate to a carboxamide. The result is an enzyme with twice the activity as the wild-type mammalian enzyme. A similar result was achieved when the C-terminal carboxylate of DmTR was converted to a hydroxamic acid or a thiocarboxylate. Last, reversing the positions of the Cys and Sec residues in the catalytic dyad resulted in a 100-fold loss of catalytic activity. Taken together, the results support our previous model of Sec as the leaving group during reduction of the C-terminus during the catalytic cycle. | lld:pubmed |
| pubmed-article:17661444 | pubmed:grant | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:17661444 | pubmed:language | eng | lld:pubmed |
| pubmed-article:17661444 | pubmed:journal | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:17661444 | pubmed:citationSubset | IM | lld:pubmed |
| pubmed-article:17661444 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:17661444 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
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| pubmed-article:17661444 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:17661444 | pubmed:status | MEDLINE | lld:pubmed |
| pubmed-article:17661444 | pubmed:month | Aug | lld:pubmed |
| pubmed-article:17661444 | pubmed:issn | 0006-2960 | lld:pubmed |
| pubmed-article:17661444 | pubmed:author | pubmed-author:HondalRobert... | lld:pubmed |
| pubmed-article:17661444 | pubmed:author | pubmed-author:LaceyBrian... | lld:pubmed |
| pubmed-article:17661444 | pubmed:author | pubmed-author:HarrisKathari... | lld:pubmed |
| pubmed-article:17661444 | pubmed:author | pubmed-author:EckenrothBria... | lld:pubmed |
| pubmed-article:17661444 | pubmed:author | pubmed-author:LothropAdam... | lld:pubmed |
| pubmed-article:17661444 | pubmed:issnType | Print | lld:pubmed |
| pubmed-article:17661444 | pubmed:day | 21 | lld:pubmed |
| pubmed-article:17661444 | pubmed:volume | 46 | lld:pubmed |
| pubmed-article:17661444 | pubmed:owner | NLM | lld:pubmed |
| pubmed-article:17661444 | pubmed:authorsComplete | Y | lld:pubmed |
| pubmed-article:17661444 | pubmed:pagination | 9472-83 | lld:pubmed |
| pubmed-article:17661444 | pubmed:dateRevised | 2007-11-15 | lld:pubmed |
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| pubmed-article:17661444 | pubmed:meshHeading | pubmed-meshheading:17661444... | lld:pubmed |
| pubmed-article:17661444 | pubmed:year | 2007 | lld:pubmed |
| pubmed-article:17661444 | pubmed:articleTitle | Investigation of the C-terminal redox center of high-Mr thioredoxin reductase by protein engineering and semisynthesis. | lld:pubmed |
| pubmed-article:17661444 | pubmed:affiliation | Department of Biochemistry, University of Vermont, 89 Beaumont Avenue, Given Laboratory, Room B413, Burlington, Vermont 05405, USA. | lld:pubmed |
| pubmed-article:17661444 | pubmed:publicationType | Journal Article | lld:pubmed |
| pubmed-article:17661444 | pubmed:publicationType | Research Support, N.I.H., Extramural | lld:pubmed |
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