Purification, crystallization and preliminary X-ray analysis of catabolic ornithine carbamoyltransferase from Pseudomonas aeruginosa

• Published in: Acta crystallographica. Section D, Biological crystallography. Vol. 55; no. 9; pp. 1591 - 1593
• Main Authors: Sainz, G., Vicat, J., Kahn, R., Tricot, C., Stalon, V., Dideberg, O.
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.09.1999
• Subjects: Bacterial Proteins - chemistry; Bacterial Proteins - isolation & purification; Bacterial Proteins - metabolism; carbamoyltransferase; Catalysis; Crystallization; Crystallography, X-Ray; Ornithine Carbamoyltransferase - chemistry; Ornithine Carbamoyltransferase - isolation & purification; Ornithine Carbamoyltransferase - metabolism; Protein Conformation; Pseudomonas aeruginosa - enzymology
• ISSN: 1399-0047; 0907-4449; 1399-0047
• DOI: 10.1107/S0907444999007970

The catabolic ornithine carbamoyltransferase (OTCase) from Pseudomonas aeruginosa exhibits allosteric behaviour, with two conformational states of the molecule: an active R form and an inactive T form. The enzyme is a dodecamer with a molecular mass of 455700 Da. Three crystal forms have been obtained. Crystals of allosteric state T are rhombohedral, belonging to the R3 space group, with hexagonal unit‐cell parameters a = b = 180.6, c = 122.0 Å. They diffract to a resolution of 4.5 Å. Two crystal forms for allosteric state R have been obtained, with hexagonal and cubic symmetries. Hexagonal crystals, which diffract to a resolution of 3.4 Å, belong to the space group P63 with unit‐cell parameters a = b = 140.8, c = 145.6 Å. The cubic crystals belong to space group I23, with unit‐cell parameter a = 134.32 Å and diffract to a resolution better than 2.5 Å. In all crystal forms, the dodecamer exhibits a 23 point‐group symmetry.