Biochemical Characterization and Complete Conversion of Coenzyme Specificity of Isocitrate Dehydrogenase from Bifidobacterium longum.
Int J Mol Sci
; 17(3): 296, 2016 Feb 26.
Article
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| MEDLINE
| ID: mdl-26927087
ABSTRACT
Bifidobacterium longum is a very important gram-positive non-pathogenic bacterium in the human gastrointestinal tract for keeping the digestive and immune system healthy. Isocitrate dehydrogenase (IDH) from B. longum (BlIDH), a novel member in Type II subfamily, was overexpressed, purified and biochemically characterized in detail. The active form of BlIDH was an 83-kDa homodimer. Kinetic analysis showed BlIDH was a NADPâº-dependent IDH (NADP-IDH), with a 567- and 193-fold preference for NADP⺠over NAD⺠in the presence of Mg(2+) and Mn(2+), respectively. The maximal activity for BlIDH occurred at 60 °C (with Mn(2+)) and 65 °C (with Mg(2+)), and pH 7.5 (with Mn(2+)) and pH 8.0 (with Mg(2+)). Heat-inactivation profiles revealed that BlIDH retained 50% of maximal activity after incubation at 45 °C for 20 min with either Mn(2+) or Mg(2+). Furthermore, the coenzyme specificity of BlIDH can be completely reversed from NADP⺠to NAD⺠by a factor of 2387 by replacing six residues. This current work, the first report on the coenzyme specificity conversion of Type II NADP-IDHs, would provide better insight into the evolution of NADP⺠use by the IDH family.
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Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas Bacterianas
/
Bifidobacterium
/
Coenzimas
/
Isocitrato Deshidrogenasa
Idioma:
En
Revista:
Int J Mol Sci
Año:
2016
Tipo del documento:
Article
País de afiliación:
China