Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
39
pubmed:dateCreated
1991-2-28
pubmed:abstractText
The effect of lipid ordering on the kinetics and extent of metarhodopsin II (meta II) formation was evaluated in bovine rhodopsin which had been reconstituted into phosphatidylcholine vesicles containing 0, 15, and 30 mol% cholesterol. The rate of establishment of the dynamic equilibrium between metarhodopsin I (meta I) and the two kinetically distinguished forms of meta II in the branched meta II model [meta IIfast and meta IIslow; Straume, M., Mitchell, D. C., Miller, J. L., & Litman, B. J. (1990) Biochemistry (preceding paper in this issue)] is derived from kinetic measurements of rhodopsin photolysis in these vesicle systems at several temperatures. Values of the meta I in equilibrium with meta IItotal equilibrium constant, Keq, are calculated from the derived model-dependent rate constants, and are shown to be equivalent to those derived from rapidly acquired absorbance spectra. The presence of 30 mol% cholesterol reduces Keq by approximately 50% between 10 and 37 degrees C. Analysis of the model-dependent parameters in terms of delta H and delta S reveals that cholesterol raises the free energy of meta IIslow, relative to meta I, by increasing delta H whereas it raises the relative free energy of meta IIfast by making delta S meta IIfast relative to meta I less positive. The reduction in Keq by both temperature and cholesterol is found to be directly correlated with a parameter that reflects the free volume available for molecular motion in the hydrophobic core of the bilayer [Straume, M., & Litman, B. J. (1988) Biochemistry 27, 7723-7733].(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9143-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Modulation of metarhodopsin formation by cholesterol-induced ordering of bilayer lipids.
pubmed:affiliation
Department of Biochemistry, University of Virginia Health Sciences Center, Charlottesville 22908.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.