The crystal structure of urease from Klebsiella aerogenes.
Science
; 268(5213): 998-1004, 1995 May 19.
Article
em En
| MEDLINE
| ID: mdl-7754395
ABSTRACT
The crystal structure of urease from Klebsiella aerogenes has been determined at 2.2 A resolution and refined to an R factor of 18.2 percent. The enzyme contains four structural domains three with novel folds playing structural roles, and an (alpha beta)8 barrel domain, which contains the bi-nickel center. The two active site nickels are 3.5 A apart. One nickel ion is coordinated by three ligands (with low occupancy of a fourth ligand) and the second is coordinated by five ligands. A carbamylated lysine provides an oxygen ligand to each nickel, explaining why carbon dioxide is required for the activation of urease apoenzyme. The structure is compatible with a catalytic mechanism whereby urea ligates Ni-1 to complete its tetrahedral coordination and a hydroxide ligand of Ni-2 attacks the carbonyl carbon. A surprisingly high structural similarity between the urease catalytic domain and that of the zinc-dependent adenosine deaminase reveals a remarkable example of active site divergence.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Urease
/
Klebsiella pneumoniae
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Science
Ano de publicação:
1995
Tipo de documento:
Article
País de afiliação:
Estados Unidos