1FB5
LOW RESOLUTION STRUCTURE OF OVINE ORNITHINE TRANSCARBMOYLASE IN THE UNLIGANDED STATE
Summary for 1FB5
| Entry DOI | 10.2210/pdb1fb5/pdb |
| Related | 1OTH |
| Descriptor | ORNITHINE TRANSCARBAMOYLASE, NORVALINE (3 entities in total) |
| Functional Keywords | cooperativity, t-state, ornithine, transferase |
| Biological source | Ovis aries (sheep) |
| Cellular location | Mitochondrion matrix: P00480 |
| Total number of polymer chains | 1 |
| Total formula weight | 36005.36 |
| Authors | Zanotti, G.,Battistutta, R.,Panzalorto, M.,Francescato, P.,Bruno, G.,De Gregorio, A. (deposition date: 2000-07-14, release date: 2003-08-26, Last modification date: 2024-03-13) |
| Primary citation | De Gregorio, A.,Battistutta, R.,Arena, N.,Panzalorto, M.,Francescato, P.,Valentini, G.,Bruno, G.,Zanotti, G. Functional and structural characterization of ovine ornithine transcarbamoylase. Org.Biomol.Chem., 1:3178-3185, 2003 Cited by PubMed Abstract: Ornithine transcarbamoylase from ovine liver has been purified to homogeneity. Like all anabolic OTCs, the ovine enzyme is a trimer, constituted by identical subunits of 34 kDa. Sequence analysis of the 54 N-terminal residues of ovine OTC shows a high degree of homology with the human enzyme. The optimum pH and the Michaelis constants for the catalytic reaction were determined. The ovine enzyme is the most thermostable one among mammals OTCs, its critical temperature being 6 degrees C higher than those measured for the other enzymes. The enzyme has been crystallised and the structure determined at 3.5 A resolution. Crystals belong to the cubic P4(3)32 space group, with a = b = c = 184.7 A and a solvent content of about 80%. There is no evidence of any ligand in the active site cavity, indicating that the crystals contain an unliganded or T state of the enzyme. The unliganded OTCase enzyme adopts a trimeric structure which, in the crystal, presents a three-fold axis coincident with the crystallographic one. The conformation of each monomer in the trimer is quite similar to that of the liganded human protein, with the exception of a few loops, directly interacting with the substrate(s), which are able to induce a rearrangement of the quaternary organisation of the trimer, that accounts for the cooperative behaviour of the enzyme following the binding of the substrates. PubMed: 14527149DOI: 10.1039/b304901a PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.5 Å) |
Structure validation
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