Linked Life Data

8117724

Source:http://linkedlifedata.com/resource/pubmed/id/8117724

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1994-4-7
pubmed:abstractText
TP40 is a chimeric protein containing transforming growth factor-alpha (TGF-alpha) at the N-terminus and a Cys-->Ala mutant (PE40 delta Cys) of a 40,000-dalton segment (PE40) of Pseudomonas exotoxin (PE). The guanidine hydrochloride (Gdn-HCl)-induced unfolding of TP40 and PE40 delta Cys has been studied by tryptophan fluorescence, circular dichroism (CD), and high-performance size exclusion chromatography (HPSEC). The equilibrium unfolding of both proteins involves at least one intermediate (I). In the I state(s), which may be induced by 1.3-2.0 M Gdn-HCl, the tertiary structure is fully or partially collapsed as detected by tryptophan fluorescence and near-UV CD, but the protein largely retains the native secondary structure and a semicompact shape as judged by far-UV CD and HPSEC, respectively. Soluble aggregates of TP40 and PE40 delta Cys are observed in addition to monomers at these intermediate (but not at higher) Gdn-HCl concentrations, suggesting that self-association is possibly mediated by thermodynamically stable, partially unfolded I states. The kinetics of refolding of TP40 upon dilution of Gdn-HCl involve two or more phases. Re-formation of secondary structure occurs rapidly (t 1/2 < 10 s) as determined by CD and is followed by a biphasic refolding of the native tertiary structure as detected by changes in tryptophan fluorescence. The midpoint (Tm) of the thermal unfolding transition occurs at a lower temperature when measured by tryptophan fluorescence than when detected by DSC and CD. These data suggest that Gdn-HCl and temperature can induce conformation(s) of TP40 that are distinct from native (N) and unfolded (U) states.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
8
pubmed:volume
33
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2620-7
pubmed:dateRevised
2005-11-17
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Evidence for an equilibrium intermediate in the folding-unfolding pathway of a transforming growth factor-alpha-Pseudomonas exotoxin hybrid protein.
pubmed:affiliation
Department of Pharmaceutical Research, Merck Research Laboratories, West Point, Pennsylvania 19486.
pubmed:publicationType
Journal Article