1FB5

LOW RESOLUTION STRUCTURE OF OVINE ORNITHINE TRANSCARBMOYLASE IN THE UNLIGANDED STATE

1FB5 の概要

• エントリーDOI: 10.2210/pdb1fb5/pdb
• 関連するPDBエントリー: 1OTH
• 分子名称: ORNITHINE TRANSCARBAMOYLASE, NORVALINE (3 entities in total)
• 機能のキーワード: cooperativity, t-state, ornithine, transferase
• 由来する生物種: Ovis aries (sheep)
• 細胞内の位置: Mitochondrion matrix: P00480
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 36005.36

構造登録者

Zanotti, G.,Battistutta, R.,Panzalorto, M.,Francescato, P.,Bruno, G.,De Gregorio, A. (登録日: 2000-07-14, 公開日: 2003-08-26, 最終更新日: 2024-03-13)

主引用文献

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

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: 14527149
DOI: 10.1039/b304901a

実験手法

X-RAY DIFFRACTION (3.5 Å)