Linked Life Data

10499104

Source:http://linkedlifedata.com/resource/pubmed/id/10499104

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1999-10-28
pubmed:abstractText
A series of ferric and ferrous derivatives of wild-type ascorbate peroxidase (APX) and of an engineered K(+)-site mutant of APX that has had its potassium cation binding site removed have been examined by electronic absorption and magnetic circular dichroism (MCD) spectroscopy at 4 degrees C. Wild-type ferric APX has spectroscopic properties that are very similar to those of ferric cytochrome c peroxidase (CCP) and likely exists primarily as a five-coordinate high-spin heme ligated on the proximal side by a histidine at pH 7. There is also evidence for minority contributions from six-coordinate high- and low-spin species (histidine-water, histidine-hydroxide, and bis-histidine). The K(+)-site mutant of APX varies considerably in the electronic absorption and MCD spectra in both the ferric and ferrous states when compared with spectra of the wild-type APX. The electronic absorption and MCD spectra of the engineered K(+)-site APX mutant are essentially identical to those of cytochrome b5, a known bis-imidazole (histidine) ligated heme system. It therefore appears that the K(+)-site mutant of APX has undergone a conformational change to yield a bis-histidine coordination structure in both the ferric and ferrous oxidation states at neutral pH. This conformational change is the result of mutagenesis of the protein to remove the K(+)-binding site which is located approximately 8 A from the peroxide binding pocket. Thus, mutations of protein residues on the proximal side of the heme cause changes in iron ligation on the distal side.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0949-8257
pubmed:author
pubmed:issnType
Print
pubmed:volume
4
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
64-72
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
A study of the K(+)-site mutant of ascorbate peroxidase: mutations of protein residues on the proximal side of the heme cause changes in iron ligation on the distal side.
pubmed:affiliation
Department of Chemistry and Biochemistry, University of South Carolina, Columbia 29208, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.