Linked Life Data

9426601

Source:http://linkedlifedata.com/resource/pubmed/id/9426601

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1998-1-26
pubmed:abstractText
Protein import into mitochondria involves several components of the mitochondrial outer and inner membranes as well as molecular chaperones located inside mitochondria. Here, we have investigated the effect of sulfhydryl group reagents on import of the in vitro transcribed/translated precursor of the F1 beta subunit of the ATP synthase (pF1 beta) into Solanum tuberosum mitochondria. We have used a reducing agent, dithiothreitol (DTT), a membrane-permeant alkylating agent, N-ethylmaleimide (NEM), a non-permeant alkylating agent, 3-(N-maleimidopropionyl)biocytin (MPB), an SH-group specific agent and cross-linker 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) as well as an oxidizing cross-linker, copper sulfate. DTT stimulated the mitochondrial protein import, whereas NEM, MPB, DTNB and Cu2+ were inhibitory. Inhibition by Cu2+ could be reversed by addition of DTT. The efficiency of inhibition was higher in energized mitochondrial than in non-energized. We have dissected the effect of the SH-group reagents on binding, unfolding and transport of the precursor into mitochondria. Our results demonstrated that the inhibitory effect of NEM, DTNB and Cu2+ on the efficiency of import was not due to the interaction of the SH-group reagents with import receptors. Modification of pF1 beta with NEM prior to the import resulted in stimulation of import, whereas DTNB and Cu2+ were inhibitory. NEM, MPB, DTNB and Cu2+ inhibited import of the NEM-modified pF1 beta into intact mitochondria. Import of pF1 beta through a receptor-independent bypass-route as well as import into mitoplasts were sensitive to DTT, NEM, MPB, DTNB and Cu2+ in a similar manner as import into mitochondria. As MPB does not cross the inner membrane, these results indicated that redox and conformational status of SH groups located on the outer surface of the inner mitochondrial membrane were essential for protein import.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0167-4412
pubmed:author
pubmed:issnType
Print
pubmed:volume
35
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
809-20
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Mitochondrial protein import: modification of sulfhydryl groups of the inner mitochondrial membrane import machinery in Solanum tuberosum inhibits protein import.
pubmed:affiliation
Department of Biochemistry, Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't