Enhanced degradation of chemical warfare agents through molecular engineering of the phosphotriesterase active site.
J Am Chem Soc
; 125(30): 8990-1, 2003 Jul 30.
Article
em En
| MEDLINE
| ID: mdl-15369336
ABSTRACT
The bacterial phosphotriesterase has been utilized as a template for the evolution of improved enzymes for the catalytic decomposition of organophosphate nerve agents. A combinatorial library of active site mutants was constructed by randomizing residues His-254, His-257, and Leu-303. The collection of mutant proteins was screened for the ability to hydrolyze a chromogenic analogue of the most toxic stereoisomer of the chemical warfare agent, soman. The mutant H254G/H257W/L303T catalyzed the hydrolysis of the target substrate nearly 3 orders of magnitude faster than the wild-type enzyme. The X-ray crystal structure was solved in the presence and absence of diisopropyl methyl phosphonate. The mutant enzyme was ligated to an additional divalent cation at the active site that was displaced upon the binding of the substrate analogue inhibitor. These studies demonstrate that substantial changes in substrate specificity can be achieved by relatively minor changes to the primary amino acid sequence.
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Base de dados:
MEDLINE
Assunto principal:
Substâncias para a Guerra Química
/
Hidrolases de Triester Fosfórico
Tipo de estudo:
Clinical_trials
Idioma:
En
Ano de publicação:
2003
Tipo de documento:
Article