Linked Life Data

9398336

Source:http://linkedlifedata.com/resource/pubmed/id/9398336

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
50
pubmed:dateCreated
1998-1-27
pubmed:abstractText
In AAC2 from Saccharomyces cerevisiae, nine additional charged residues (six positive, three negative) were neutralized by mutagenesis following the previous mutation of six arginines. Oxidative phosphorylation (OxPhos) in cells and mitochondria, the expression level of AAC protein, and the various transport modes of AAC in the reconstituted system were measured. Mutations are: within the first helix at K38A which is exclusive for AAC; K48A, and R152A, part of a positive triad occurring in the matrix portion of each repeat; two matrix lysines, K179M and K182I, and the negative triad helix-terminating residues, E45G, D149S, D249S. Cellular ATP synthesis (OxPhos) is nearly completely inhibited in K48A, R152A, D149S, and D249S, but still amounts to 10% in K38A and between 30% and 90% in the gly+ mutants K179M, K179I + K182I, and E45G. Comparison of the AAC content measured by ELISA and the binding of [3H]CAT and [3H]BKA reveals discrepancies in K48A, D149S, and D249S mitochondria, which provide evidence that these mutations largely abolish inhibitor binding. Also these mitochondria have undetectable OxPhos. Differently in K38A, CAT and BKA binding are retained at high AAC levels but OxPhos is very low. This reveals a special functional role of K38, different from the more structural role of R152, K48, D149, and D249. Transport activity was measured with reconstituted AAC. The electroneutral ADP/ADP exchange of gly- mutants is largely or fully suppressed in K48A, D149S, and D249S. K38A and R152A are still active at 18% and 30% of wt. The other three exchange modes, ATP/ADP, ADP/ATP, and ATP/ATP, are nearly suppressed in all gly- mutants but remain high in gly+ mutants. ATP-linked modes are higher than the ADP/ADP mode in gly+ but lower in gly- mutants, resulting in an exchange mode inversion (EMI). In the competition for AAC2 transport capacity, the weak ATP exporting modes are suppressed by the much stronger unproductive ADP/ADP mode causing inhibition of OxPhos. Together with previous results all members of three charge triads are now mutagenized, revealing drastic functional rotatory asymmetries within the three repeat domains. In the intrahelical arginine triad the third (R294A), in the positive matrix triad the second (R152A), and in the helix-terminating negative triad the first (E45G) still show high activity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
16008-18
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:9398336-Adenosine Triphosphate, pubmed-meshheading:9398336-Amino Acid Sequence, pubmed-meshheading:9398336-Anti-Bacterial Agents, pubmed-meshheading:9398336-Atractyloside, pubmed-meshheading:9398336-Biological Transport, pubmed-meshheading:9398336-Bongkrekic Acid, pubmed-meshheading:9398336-Cell Respiration, pubmed-meshheading:9398336-Cytochrome c Group, pubmed-meshheading:9398336-Enzyme-Linked Immunosorbent Assay, pubmed-meshheading:9398336-Immunoblotting, pubmed-meshheading:9398336-Liposomes, pubmed-meshheading:9398336-Membrane Proteins, pubmed-meshheading:9398336-Mitochondria, pubmed-meshheading:9398336-Mitochondrial ADP, ATP Translocases, pubmed-meshheading:9398336-Molecular Sequence Data, pubmed-meshheading:9398336-Mutagenesis, pubmed-meshheading:9398336-Oxidative Phosphorylation, pubmed-meshheading:9398336-Protein Binding, pubmed-meshheading:9398336-Saccharomyces cerevisiae
pubmed:year
1997
pubmed:articleTitle
Mutagenesis of some positive and negative residues occurring in repeat triad residues in the ADP/ATP carrier from yeast.
pubmed:affiliation
Institute of Physical Biochemistry, University of Munich, Schillerstrasse 44, 80336 Munich, Germany.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't