Linked Life Data

6408078

Source:http://linkedlifedata.com/resource/pubmed/id/6408078

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
1983-8-11
pubmed:abstractText
Our previous in vivo studies demonstrated that large premature fragments of beta-galactosidase are degraded in Escherichia coli by a common pathway, and the initial event appears to be a site-specific cleavage (McKnight, J. L., and Fried, V. A. (1981) J. Biol. Chem. 256, 9652-9661). We now have developed a cell-free system that retains the specificity of this early cleavage event. Immunochemical techniques were used to isolate and quantitate the polypeptide substrate and products in pulse-chase experiments. The in vitro system has an activity that quantitatively converts the prematurely terminated A polypeptide of the lacZ non-sense mutant CSH-10 to the 90-kilodalton common B polypeptide intermediate observed in vivo. The activity is localized in the cytoplasm since the cleavage reaction is not affected by osmotic shock of whole cells or removal of the membrane fraction from cell-free extracts. The lon mutation capR9, which blocks this degradation pathway in vivo, does not affect the initial cleavage event in cell-free extracts of CSH-10 carrying this mutation. The in vitro cleavage event in extracts of lon+ CSH-10 or the isogenic lon- mutant is not stimulated by addition of ATP, not inhibited by depletion of ATP pools by hexokinase-2-deoxyglucose treatment, and not inhibited by EDTA or phenylmethylsulfonyl fluoride. These results suggest that the ATP-dependent proteolytic activity of the lon gene product does not directly catalyze this primary cleavage event.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7550-5
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
A novel proteolytic activity apparently initiating degradation of beta-galactosidase nonsense fragments in in vitro extracts of Escherichia coli.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't