Linked Life Data

19616643

Source:http://linkedlifedata.com/resource/pubmed/id/19616643

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2009-11-16
pubmed:abstractText
Seven of the 45 subunits of mitochondrial NADH:ubiquinone oxidoreductase (complex I) are mitochondrially encoded and have been shown to harbor pathogenic mutations. We modeled the human disease-associated mutations A4136G/ND1-Y277C, T4160C/ND1-L285P and C4171A/ND1-L289M in a highly conserved region of the fourth matrix-side loop of the ND1 subunit by mutating homologous amino acids and surrounding conserved residues of the NuoH subunit of Escherichia coli NDH-1. Deamino-NADH dehydrogenase activity, decylubiquinone reduction kinetics, hexammineruthenium (HAR) reductase activity, and the proton pumping efficiency of the enzyme were assayed in cytoplasmic membrane preparations. Among the human disease-associated mutations, a statistically significant 22% decrease in enzyme activity was observed in the NuoH-L289C mutant and a 29% decrease in the double mutant NuoH-L289C/V297P compared with controls. The adjacent mutations NuoH-D295A and NuoH-R293M caused 49% and 39% decreases in enzyme activity, respectively. None of the mutations studied significantly affected the K(m) value of the enzyme for decylubiquinone or the amount of membrane-associated NDH-1 as estimated from the HAR reductase activity. In spite of the decrease in enzyme activity, all the mutant strains were able to grow on malate, which necessitates sufficient NDH-1 activity. The results show that in ND1/NuoH its fourth matrix-side loop is probably not directly involved in ubiquinone binding or proton pumping but has a role in modifying enzyme activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1872-8278
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
9
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
394-401
pubmed:meshHeading
pubmed-meshheading:19616643-Amino Acid Sequence, pubmed-meshheading:19616643-Amino Acid Substitution, pubmed-meshheading:19616643-Escherichia coli, pubmed-meshheading:19616643-Escherichia coli Proteins, pubmed-meshheading:19616643-Humans, pubmed-meshheading:19616643-Kinetics, pubmed-meshheading:19616643-Malates, pubmed-meshheading:19616643-Membrane Proteins, pubmed-meshheading:19616643-Models, Molecular, pubmed-meshheading:19616643-Molecular Sequence Data, pubmed-meshheading:19616643-Mutagenesis, Site-Directed, pubmed-meshheading:19616643-Mutation, Missense, pubmed-meshheading:19616643-NADH Dehydrogenase, pubmed-meshheading:19616643-Protein Structure, Quaternary, pubmed-meshheading:19616643-Proton Pumps, pubmed-meshheading:19616643-Ruthenium Compounds, pubmed-meshheading:19616643-Ubiquinone
pubmed:year
2009
pubmed:articleTitle
Modeling of human pathogenic mutations in Escherichia coli complex I reveals a sensitive region in the fourth inside loop of NuoH.
pubmed:affiliation
Department of Medical Biochemistry and Molecular Biology, Institute of Biomedicine, University of Oulu, Finland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't