Linked Life Data

7836387

Source:http://linkedlifedata.com/resource/pubmed/id/7836387

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1995-2-24
pubmed:abstractText
In the human placental glutathione transferase, Cys-47 possesses, at physiological pH values, a pK alpha value of 4.2 and may exist as an ion pair with the protonated epsilon-amino group of Lys-54. Using site-directed mutagenesis we investigate spectral, kinetic, and structural properties of Cys-47 and Lys-54 mutants. The results shown indicate that the thiolate ion detected at 229 nm should be assigned exclusively to Cys-47. The contribution of Lys-54 to the activation of Cys-47 is assessed by the spectral properties of the K54A mutant enzyme. The induced cooperativity toward glutathione, as a consequence of mutation of Lys-54 to alanine, clearly parallels that observed for the Cys-47 mutant enzymes (see the preceding paper (Ricci, G., Lo Bello, M., Caccuri, A. M., Pastore, A., Nuccetelli, M., Parker, M. W., and Federici, G. (1995) J. Biol. Chem. 270, 1243-1248) and points out the importance of this electrostatic interaction in shaping the correct spatial arrangement for the binding of glutathione and in anchoring the flexible helix alpha 2. When this ion pair is disrupted, by mutation of either residue, the flexibility of this region could be greatly increased, causing helix alpha 2 to come in contact with the other subunit and generating a structural communication, which is the basis of the observed cooperativity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1249-53
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Site-directed mutagenesis of human glutathione transferase P1-1. Spectral, kinetic, and structural properties of Cys-47 and Lys-54 mutants.
pubmed:affiliation
Department of Biology, University of Rome Tor Vergata, Rome, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't