Metabolic channeling of carbamoyl phosphate, a thermolabile intermediate: evidence for physical interaction between carbamate kinase-like carbamoyl-phosphate synthetase and ornithine carbamoyltransferase from the hyperthermophile Pyrococcus furiosus.
Two different approaches provided evidence for a physical interaction between the carbamate kinase-like carbamoyl-phosphate synthetase (CKase) and ornithine carbamoyltransferase (OTCase) from the hyperthermophilic archaeon Pyrococcus furiosus. Affinity electrophoresis indicated that CKase and OTCase associate into a multienzyme cluster. Further evidence for a biologically significant interaction between CKase and OTCase was obtained by co-immunoprecipitation combined with formaldehyde cross-linking experiments. These experiments support the hypothesis that CKase and OTCase form an efficient channeling cluster for carbamoyl phosphate, an extremely thermolabile and potentially toxic metabolic intermediate. Therefore, by physically interacting with each other, CKase and OTCase prevent the thermodenaturation of carbamoyl phosphate in the aqueous cytoplasmic environment.
Massant
Jan
J
Department of Microbiology, Vrije Universiteit Brussel, Flanders Interuniversity Institute for Biotechnology, Université Libre de Bruxelles, Belgium.
Verstreken
Patrik
P
Durbecq
Virginie
V
Kholti
Abdelaziz
A
Legrain
Christianne
C
Beeckmans
Sonia
S
Cornelis
Pierre
P
Glansdorff
Nicolas
N
D002221:Carbamyl Phosphate / Q000378:metabolism*; D019731:Carbon-Nitrogen Ligases / Q000378:metabolism*; D004586:Electrophoresis / Q000379:methods; D006868:Hydrolysis; D009954:Ornithine Carbamoyltransferase / Q000378:metabolism*; D017851:Phosphotransferases (Carboxyl Group Acceptor) / Q000378:metabolism*; D011233:Precipitin Tests; D020027:Pyrococcus furiosus / Q000201:enzymology*
D002221:Carbamyl Phosphate; D009954:Ornithine Carbamoyltransferase; D017851:Phosphotransferases (Carboxyl Group Acceptor); C019288:carbamate kinase; D019731:Carbon-Nitrogen Ligases