The tail of KdsC: conformational changes control the activity of a haloacid dehalogenase superfamily phosphatase.
J Biol Chem
; 284(44): 30594-603, 2009 Oct 30.
Article
em En
| MEDLINE
| ID: mdl-19726684
ABSTRACT
The phosphatase KdsC cleaves 3-deoxy-D-manno-octulosonate 8-phosphate to generate a molecule of inorganic phosphate and Kdo. Kdo is an essential component of the lipopolysaccharide envelope in Gram-negative bacteria. Because lipopolysaccharide is an important determinant of bacterial resistance and toxicity, KdsC is a potential target for novel antibacterial agents. KdsC belongs to the broad haloacid dehalogenase superfamily. In haloacid dehalogenase superfamily enzymes, substrate specificity and catalytic efficiency are generally dictated by a fold feature called the cap domain. It is therefore not clear why KdsC, which lacks a cap domain, is catalytically efficient and highly specific to 3-deoxy-D-manno-octulosonate 8-phosphate. Here, we present a set of seven structures of tetrameric Escherichia coli KdsC (ranging from 1.4 to 3.06 A in resolution) that model different intermediate states in its catalytic mechanism. A crystal structure of product-bound E. coli KdsC shows how the interface between adjacent monomers defines the active site pocket. Kdo is engaged in a network of polar and nonpolar interactions with residues at this interface, which explains substrate specificity. Furthermore, this structural and kinetic analysis strongly suggests that the binding of the flexible C-terminal region (tail) to the active site makes KdsC catalytically efficient by facilitating product release.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Monoéster Fosfórico Hidrolases
/
Proteínas de Escherichia coli
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Hidrolases
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Estados Unidos