Structural and functional characterization of a noncanonical nucleoside triphosphate pyrophosphatase from Thermotoga maritima.
Acta Crystallogr D Biol Crystallogr
; 69(Pt 2): 184-93, 2013 Feb.
Article
en En
| MEDLINE
| ID: mdl-23385455
The hyperthermophilic bacterium Thermotoga maritima has a noncanonical nucleoside triphosphatase that catalyzes the conversion of inosine triphosphate (ITP), deoxyinosine triphosphate (dITP) and xanthosine triphosphate (XTP) into inosine monophosphate (IMP), deoxyinosine monophosphate (IMP) and xanthosine monophosphate (XMP), respectively. The k(cat)/K(m) values determined at 323 and 353 K fall between 1.31 × 10(4) and 7.80 × 10(4) M(-1) s(-1). ITP and dITP are slightly preferred over XTP. Activity towards canonical nucleoside triphosphates (ATP and GTP) was not detected. The enzyme has an absolute requirement for Mg(2+) as a cofactor and has a preference for alkaline conditions. A protein X-ray structure of the enzyme with bound IMP was obtained at 2.15 Å resolution. The active site houses a well conserved network of residues that are critical for substrate recognition and catalysis. The crystal structure shows a tetramer with two possible dimer interfaces. One of these interfaces strongly resembles the dimer interface that is found in the structures of other noncanonical nucleoside pyrophosphatases from human (human ITPase) and archaea (Mj0226 and PhNTPase).
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Pirofosfatasas
/
Proteínas Bacterianas
/
Thermotoga maritima
Tipo de estudio:
Clinical_trials
Límite:
Humans
Idioma:
En
Revista:
Acta Crystallogr D Biol Crystallogr
Año:
2013
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos