Crystal structure of the hexameric catabolic ornithine transcarbamylase from Lactobacillus hilgardii: Structural insights into the oligomeric assembly and metal binding.
J Mol Biol
; 393(2): 425-34, 2009 Oct 23.
Article
em En
| MEDLINE
| ID: mdl-19666033
ABSTRACT
Catabolic ornithine transcarbamylase (cOTC; EC 2.1.3.3) catalyzes the formation of ornithine (ORN) and carbamoyl phosphate from citrulline, which constitutes the second step of the degradation of arginine via the arginine deiminase pathway. Here, we report the crystal structure of cOTC from the lactic acid bacteria Lactobacillus hilgardii (Lh-cOTC) refined to 2.1 A resolution. The structure reveals that Lh-cOTC forms a hexameric assembly, which was also confirmed by gel-filtration chromatography and analytical ultracentrifugation. The homohexamer, with 32 point group symmetry, represents a new oligomeric state within the members of the ornithine transcarbamylase family that are typically homotrimeric or homododecameric. The C-terminal end from each subunit constitutes a key structural element for the stabilization of the hexameric assembly in solution. Additionally, the structure reveals, for the first time in the ornithine transcarbamylase family, a metal-binding site located at the 3-fold molecular symmetry axis of each trimer.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Ornitina Carbamoiltransferase
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Proteínas de Bactérias
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Cristalografia por Raios X
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Níquel
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article