1pvv

Publication Abstract from PubMed

Using synchrotron radiation, X-ray data have been collected from Pyrococcus furiosus ornithine carbamoyltransferase (Pfu OTCase) to a maximal resolution of 1.87 A, allowing the refinement of a previous structure at 2.7 A [Villeret et al. (1998), Proc. Natl Acad. Sci. USA, 95, 2801-2806]. Thanks to the high resolution of this refined structure, two sulfate ions and 191 water molecules could be localized directly from the electron-density maps. The identification of these molecules allowed a more rigorous description of the active site and the identification of residues involved in binding carbamoyl phosphate. The improved quality of the model resulted in a better definition of several loops and the various interfaces. The dodecameric protein is composed of four catalytic trimers disposed in a tetrahedral manner. The extreme thermal stability of Pfu OTCase is mainly the result of the strengthening of the intersubunit interactions in a trimer and oligomerization of the trimers into a dodecamer. Interfaces between monomers in a catalytic trimer are characterized by an increase in ion-pair networks compared with mesophilic OTCases. However, the interfaces between catalytic trimers in the dodecameric oligomer are mainly hydrophobic and also involve aromatic-aromatic and cation-pi interactions.

Refined structure of Pyrococcus furiosus ornithine carbamoyltransferase at 1.87 A.,Massant J, Wouters J, Glansdorff N Acta Crystallogr D Biol Crystallogr. 2003 Dec;59(Pt 12):2140-9. Epub 2003, Nov 27. PMID:14646072^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.