TY - JOUR
T1 - Refined structure of Pyrococcus furiosus ornithine carbamoyltransferase at 1.87 A
AU - Massant, Jan
AU - Wouters, Johan
AU - Glansdorff, Nicolas
PY - 2003/12/1
Y1 - 2003/12/1
N2 - Using synchrotron radiation, X-ray data have been collected from Pyrococcus furiosus ornithine carbamoyltransferase (Pfu OTCase) to a maximal resolution of 1.87 Å, allowing the refinement of a previous structure at 2.7 Å [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-π interactions.
AB - Using synchrotron radiation, X-ray data have been collected from Pyrococcus furiosus ornithine carbamoyltransferase (Pfu OTCase) to a maximal resolution of 1.87 Å, allowing the refinement of a previous structure at 2.7 Å [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-π interactions.
UR - http://www.scopus.com/inward/record.url?scp=0347062345&partnerID=8YFLogxK
U2 - 10.1107/S0907444903019231
DO - 10.1107/S0907444903019231
M3 - Article
C2 - 14646072
AN - SCOPUS:0347062345
SN - 0907-4449
VL - 59
SP - 2140
EP - 2149
JO - Acta crystallographica. Section D: Biological crystallography
JF - Acta crystallographica. Section D: Biological crystallography
IS - 12
ER -