Linked Life Data

10845705

Source:http://linkedlifedata.com/resource/pubmed/id/10845705

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2000-6-26
pubmed:abstractText
The two Cu,Zn superoxide dismutases from the amphibian Xenopus laevis (denoted XSODA and XSODB) display different heat sensitivities, XSODA being more thermolabile than XSODB. In this study, we have investigated the contribution of a free cysteine residue located close to the subunit interface of XSODA to its lower thermal stability. We have found that mutation of residue Cys 150 to Ala in XSODA makes the thermal stability of this enzyme comparable to that of the wild-type XSODB isoenzyme, while the introduction of a cysteine residue in the same position of XSODB renders this enzyme variant much more heat-sensitive. Differential scanning calorimetry experiments showed that XSODA has a melting temperature about 8.5 degrees C lower than that of XSODB. On the contrary, the melting temperature of XSODACys150Ala is very close to that of XSODB, while the melting temperature of XSODBSer150Cys is even lower than that of wild-type XSODA. These data indicate that the free cysteine residue present in XSODA affects not only the reversibility of unfolding of the enzyme but also its conformational stability. We suggest that the large effect of the Cys 150 residue on XSODA stability might be due to incorrect disulfide bond formation or disulfide bond interchange during heat-induced unfolding rather than to alteration of the interaction between the enzyme subunits.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0003-9861
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
377
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
284-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
A free cysteine residue at the dimer interface decreases conformational stability of Xenopus laevis copper,zinc superoxide dismutase.
pubmed:affiliation
Department of Biochemical Sciences A. Rossi Fanelli and CNR Center of Molecular Biology, University of Rome La Sapienza, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't