Linked Life Data

8440686

Source:http://linkedlifedata.com/resource/pubmed/id/8440686

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1993-3-26
pubmed:abstractText
The precursor to rat mitochondrial aspartate aminotransferase (pmAspAT) can be expressed in and purified from Escherichia coli as a fully active enzyme with remarkable trypsin resistance. Only two sites within the presequence are readily hydrolyzed (Martinez-Carrion, M., Altieri, F., Iriarte, A., Mattingly, J. R., Youssef, J., and Wu, T. (1990) Ann. N.Y. Acad. Sci. 585, 346-356). In contrast, pmAspAT freshly synthesized in rabbit reticulocyte lysate is significantly less resistant to proteolysis and is completely digested by trypsin. Extended incubation of the pmAspAT translation product slowly converts it to a species with qualitatively the same trypsin resistance as the purified pmAspAT. In addition, this species binds pyridoxal 5'-phosphate, exhibits catalytic activity, and loses its ability to be imported into mitochondria. This process appears to reflect protein folding. The rate of folding is unaffected by the addition of cofactor or the depletion of endogenous cofactor and is not significantly affected by the concentration of translation product in the reaction. Agents that decrease the availability of ATP partially inhibit the folding, whereas the sulfhydryl alkylating reagent N-ethylmaleimide and the detergent Triton X-100 completely prevent the conversion. Although the folding of pmAspAT in reticulocyte lysate is slow, folding is rapid once the translation product is sequestered within the mitochondria as the mature form of the enzyme. These results are presented as a model for the in vivo folding of pyridoxal-dependent, oligomeric mitochondrial precursors in the presence of cytoplasmic components and for the fate of true mitochondrial precursor proteins when not imported.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
268
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3925-37
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:8440686-Adenosine Triphosphate, pubmed-meshheading:8440686-Animals, pubmed-meshheading:8440686-Aspartate Aminotransferases, pubmed-meshheading:8440686-Biological Transport, pubmed-meshheading:8440686-Cell-Free System, pubmed-meshheading:8440686-Coenzymes, pubmed-meshheading:8440686-Detergents, pubmed-meshheading:8440686-Edetic Acid, pubmed-meshheading:8440686-Enzyme Precursors, pubmed-meshheading:8440686-Escherichia coli, pubmed-meshheading:8440686-Ethylmaleimide, pubmed-meshheading:8440686-Mitochondria, pubmed-meshheading:8440686-Octoxynol, pubmed-meshheading:8440686-Polyethylene Glycols, pubmed-meshheading:8440686-Protein Biosynthesis, pubmed-meshheading:8440686-Protein Folding, pubmed-meshheading:8440686-RNA, Messenger, pubmed-meshheading:8440686-Rabbits, pubmed-meshheading:8440686-Rats, pubmed-meshheading:8440686-Trypsin
pubmed:year
1993
pubmed:articleTitle
Protein folding in a cell-free translation system. The fate of the precursor to mitochondrial aspartate aminotransferase.
pubmed:affiliation
Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri, Kansas City 64110-2499.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.