Linked Life Data

18232645

Source:http://linkedlifedata.com/resource/pubmed/id/18232645

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2008-3-3
pubmed:abstractText
Forty-six charge-reversal mutants of yeast cytochrome c peroxidase (CcP) have been constructed in order to determine the effect of localized charge on the catalytic properties of the enzyme. The mutants include the conversion of all 20 glutamate residues and 24 of the 25 aspartate residues in CcP, one at a time, to lysine residues. In addition, two positive-to-negative charge-reversal mutants, R31E and K149D, are included in the study. The mutants have been characterized by absorption spectroscopy and hydrogen peroxide reactivity at pH 6.0 and 7.5 and by steady-state kinetic studies using recombinant yeast iso-1 ferrocytochrome c (C102T) as substrate at pH 7.5. Many of the charge-reversal mutations cause detectable changes in the absorption spectrum of the enzyme reflecting increased amounts of hexacoordinate heme compared to wild-type CcP. The increase in hexacoordinate heme in the mutant enzymes correlates with an increase in H 2O 2-inactive enzyme. The maximum velocity of the mutants decreases with increasing hexacoordination of the heme group. Steady-state velocity studies indicate that 5 of the 46 mutations (R31E, D34K, D37K, E118K, and E290K) cause large increases in the Michaelis constant indicating a reduced affinity for cytochrome c. Four of the mutations occur within the cytochrome c binding site identified in the crystal structure of the 1:1 complex of yeast cytochrome c and CcP [Pelletier, H., and Kraut, J. (1992) Science 258, 1748-1755] while the fifth mutation site lies outside, but near, the crystallographic site. These data support the hypothesis that the CcP has a single, catalytically active cytochrome c binding domain, that observed in the crystal structures of the cytochrome c/CcP complex.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
47
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2766-75
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Effect of single-site charge-reversal mutations on the catalytic properties of yeast cytochrome c peroxidase: evidence for a single, catalytically active, cytochrome c binding domain.
pubmed:affiliation
Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural