Differs from EC 18.104.22.168, ornithine carbamoyltransferase. This enzyme replaces EC 22.214.171.124 in the canonic arginine biosynthetic pathway of several Eubacteria and has no catalytic activity with L-ornithine as substrate.
Lys302 is post-translationally carboxylated. The carboxyl group on Lys302 forms a strong hydrogen bonding network with surrounding active site residues, Lys252, Ser253, His293, and Glu92 from the adjacent subunit either directly or via a water molecule. The carboxyl group is involved in binding N-acetyl-L-ornithine via a water molecule. The posttranslational modification of lysine 302 has an important role in catalysis
stochastic simulations of coarse-grained protein models used to investigate the propensity to form knots in early stages of protein folding, comparison of natively-knotted N-acetylornithine carbamoyltransferase, AOTCase, and an unknotted ornithine carbamoyltransferase, OTCase, EC 126.96.36.199, protein and amino acid interactions, mechanism, overview. The different entanglement of the two transcarbamylases follows from the tendency of the C-terminal to point away from (for OTCase) or approach and eventually thread (for AOTCase) other regions of partly-folded protein. The analysis of the OTCase/AOTCase pair clarifies that natively-knotted proteins can spontaneously knot during early folding stages and that non-native sequence-dependent interactions are important for promoting and disfavouring early knotting events. Knotting usually results from the threading of the C-terminal through loops present in the loose protein globule. Simulation of the early folding process of the two transcarbamylases, non-native interactions, kinetics, and modeling, overview
Lys302 is post-translationally carboxylated. The carboxyl group on Lys302 forms a strong hydrogen bonding network with surrounding active site residues, Lys252, Ser253, His293, and Glu92 from the adjacent subunit either directly or via a water molecule. The carboxyl group is involved in binding N-acetyl-L-ornithine via a water molecule
purified recombinant enzyme in binary complex with its substrates, carbamoyl phosphate or N-acetyl-L-ornithine, and in ternary complex with carbamoyl phosphate and N-acetyl-L-norvaline, hanging drop vapour diffusion method, preparation by mixing of 0.002 ml of 12 mg/ml protein solution with an equal volume of reservoir solution containing the ligands, cryoprotection, X-ray diffraction structure determination and analysis at 1.8-1.95 A resolution, modeling of the transition state complex
wild-type and mutant AOTCase complexed with bisubstrate analogue Ndelta-(phosphonoacetyl)-Nalpha-acetyl-L-ornithine, hanging drop vapor diffusion method, mixing of 0.002 ml 10 mg/ml protein in solution with 0.0016 ml of reservoir solution and 0.0004 ml 10 mM ligand solution. The reservoir solution contains 20% w/v PEG 3350, 0.2 M lithium sulfate, and 0.1 M Bis-Tris, pH 6.0, X-ray diffraction structure determination and analysis at 1.8-2.2 A resolution, molecular replacement
site-directed mutagenesis, the mutant shows reduced activity compared to the wild-type enzyme. The side-chain of Glu302 in the K302E mutant structure is well defined and anchored by hydrogen bonding interaction with the main-chain nitrogen atom of Arg298 and weakly hydrogen bonded to the main-chain nitrogen atom of Ser253