Linked Life Data

1447169

Source:http://linkedlifedata.com/resource/pubmed/id/1447169

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
34
pubmed:dateCreated
1992-12-30
pubmed:abstractText
The ability of the cytoplasmically synthesized mitochondrial enzyme rhodanese and its putative import signal sequence to interact with model phospholipid membranes was characterized. Membrane perturbation assays were used to test a current hypothesis that the initial step in protein translocation may involve binding of signal sequences with membrane lipids. Here we show comparative studies on the effect of native and various forms of denatured rhodanese, as well as two peptides, rho(1-23) and rho(11-23), derived from its NH2-terminal sequence, on the perturbation of 6-carboxyfluorescein-containing large unilamellar vesicles composed of either cardiolipin, phosphatidylcholine, or phosphatidylserine. We monitored the degree of perturbation by measuring dye leakage and found differential perturbation by either peptide or protein. Unfolded rhodanese perturbed vesicles in the order phosphatidylserine > cardiolipin >> phosphatidylcholine. Denatured rhodanese was approximately 25 times more effective (on a molar basis) than rho(1-23) in the disruption of anionic liposomes. Rho(11-23) was unable to perturb liposomes. We found an inverse correlation between degree of activity of rhodanese folding intermediates and their ability to perturb liposomes. On urea denaturation, enzymatic activity was completely lost before membrane perturbation ability reached significant levels. Analysis of the peptides by circular dichroism showed that anionic liposomes can induce alpha-helical structure only in rho(1-23) and denatured rhodanese. Intrinsic peptide fluorescence studies showed that only rho(1-23) and denatured rhodanese partitioned into these model membranes. Results obtained here imply that peptides from naturally occurring alpha-helical structures may need adjacent motifs for helical structure induction in lipid environments, and the subsequent secondary structure may, in turn, promote partitioning of these segments into the lipid phase and ultimately lead to membrane perturbation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
267
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
24193-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Analysis of the perturbation of phospholipid model membranes by rhodanese and its presequence.
pubmed:affiliation
Department of Biochemistry, University of Texas Health Science Center, San Antonio 78284-7760.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't