The Crystal Structure of Pyrococcus Furiosus Ornithine Carbamoyltransferase Reveals a Key Role for Oligomerization in Enzyme Stability at Extremely High Temperatures
Proc. Natl. Acad. Sci. USA Vol. 95, pp. 2801–2806, March 1998 Biochemistry The crystal structure of Pyrococcus furiosus ornithine carbamoyltransferase reveals a key role for oligomerization in enzyme stability at extremely high temperatures VINCENT VILLERET*, BERNARD CLANTIN†,CATHERINE TRICOT‡,CHRISTIANNE LEGRAIN‡,MARTINE ROOVERS§¶, i VICTOR STALON†,NICOLAS GLANSDORFF‡§¶, AND JOZEF VAN BEEUMEN* *Laboratorium voor Eiwitbiochemie en Eiwitengineering, Universiteit Gent, Ledeganckstraat 35, B-9000 Gent, Belgium; and †Laboratoire de Microbiologie, Universite´Libre de Bruxelles, ‡Institut de Recherches du Centre d’Enseignement et de Recherches des Industries Alimentaires, Commission de la Communaute´ Franc¸aise de Belgique, Re´gionBruxelles Capitale, §Laboratorium voor Erfelijkheidsleer en Microbiologie, Vrije Universiteit Brussel, and ¶Vlaams Interuniversitair Instituut voor Biotechnologie, avenue E. Gryson 1, B-1070 Brussels, Belgium Edited by Max F. Perutz, Medical Research Council, Cambridge, United Kingdom, and approved January 5, 1998 (received for review September 8, 1997) ABSTRACT The Pyrococcus furiosus (PF) ornithine car- lating agent (8). The involvement of such a thermolabile bamoyltransferase (OTCase; EC 2.1.3.3) is an extremely heat- intermediate in the metabolism of extreme thermophilic mi- stable enzyme that maintains about 50% of its activity after croorganisms raises the question of which mechanisms protect heat treatment for 60 min at 100°C. To understand the it from decomposition at elevated growth temperatures. Re- molecular basis of thermostability of this enzyme, we have cent results suggest that in Thermus aquaticus and Pyrococcus determined its three-dimensional structure at a resolution of furiosus (PF), CP is protected from the bulk of the aqueous 2.7 Å and compared it with the previously reported structures phase by channeling between carbamoylphosphate synthetase of OTCases isolated from mesophilic bacteria.
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