Reference : Influence of moderate temperatures on myristoyl-CoA metabolism and acyl-CoA thioesterase...
Scientific journals : Article
Life sciences : Microbiology
http://hdl.handle.net/2268/31552
Influence of moderate temperatures on myristoyl-CoA metabolism and acyl-CoA thioesterase activity in the psychrophilic antarctic yeast Rhodotorula aurantiaca.
English
Sabri, Ahmed mailto [Université de Liège - ULg > > Centre Wallon de biologie industrielle >]
Bare, G. [> > > >]
Jacques, P. [> > > >]
Jabrane, A. [> > > >]
Ongena, MARC mailto [Université de Liège - ULg > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech >]
Van Heugen, Jean-Claude mailto [Centre Hospitalier Universitaire de Liège - CHU > > Chimie médicale >]
Devreese, B. [> > > >]
Thonart, Philippe mailto [Université de Liège - ULg > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech - Biochimie et microbiologie industrielles >]
2001
Journal of Biological Chemistry
American Society for Biochemistry and Molecular Biology
276
16
12691-6
Yes (verified by ORBi)
International
0021-9258
1083-351X
Baltimore
MD
[en] Acyl Coenzyme A/isolation & purification/metabolism ; Antarctic Regions ; Catalysis ; Chromatography, High Pressure Liquid ; Chromatography, Ion Exchange ; Fatty Acids, Nonesterified/metabolism ; Kinetics ; Palmitoyl-CoA Hydrolase/metabolism ; Rhodotorula/growth & development/metabolism ; Substrate Specificity ; Temperature ; Thermodynamics
[en] The inability of psychrophilic microorganisms to grow at moderate temperatures (>20 degrees C) presently represents an unresolved thermodynamic paradox. Here we report for the psychrophilic yeast Rhodotorula aurantiaca A19, isolated from Antarctic ice, that the inability to grow at temperatures close to 20 degrees C is associated with profound alterations in cell morphology and integrity. High performance liquid chromatography analysis of the intracellular acyl-CoA esters revealed an abnormal accumulation of myristoyl-CoA (C14-CoA) in cells cultivated close to the nonpermissive temperature. Its concentration (500 microm) was found to be 28-fold higher than in cells cultivated at 0 degrees C. If one considers its ability to disrupt membrane bilayers and to inhibit many cellular enzymes and functions, intracellular myristoyl-CoA accumulation in the psychrophile R. aurantiaca represents one of the principal causes of growth arrest at moderate temperatures. Intracellular acyl-CoA concentrations are believed to be regulated by thioesterase activity. Thus in an attempt to explore the mechanism by which temperature disrupts myristoyl-CoA metabolism, we isolated and characterized a long chain acyl-CoA thioesterase. The monomeric 80-kDa thioesterase from the psychrophilic yeast shows a very strong specificity for myristoyl-CoA. The affinity for substrate and the catalytic efficiency of the thioesterase are optimal below 5 degrees C (temperatures habitually experienced by the strain) and dramatically decrease with increasing temperature. The loss of affinity for substrate is related to the intracellular increase of myristoyl-CoA concentration. Our observations reveal one of the probable mechanisms by which temperature fixes the limit of growth for this psychrophilic yeast.
http://hdl.handle.net/2268/31552
10.1074/jbc.M100155200

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