The crystal structure of Pyrococcus furiosus ornithine carbamoyltransferase reveals a key role for oligomerization in enzyme stability at extremely high temperatures.

ABSTRACT: The Pyrococcus furiosus (PF) ornithine carbamoyltransferase (OTCase; EC 2.1.3.3) is an extremely heat-stable enzyme that maintains about 50% of its activity after heat treatment for 60 min at 100 degrees C. To understand the molecular basis of thermostability of this enzyme, we have determined its three-dimensional structure at a resolution of 2.7 A and compared it with the previously reported structures of OTCases isolated from mesophilic bacteria. Most OTCases investigated up to now are homotrimeric and devoid of allosteric properties. A striking exception is the catabolic OTCase from Pseudomonas aeruginosa, which is allosterically regulated and built up of four trimers disposed in a tetrahedral manner, an architecture that actually underlies the allostery of the enzyme. We now report th

SUBMITTER: Villeret V 

PROVIDER: S-EPMC19649 | biostudies-literature | 1998 Mar

REPOSITORIES: biostudies-literature