Construction of co-expression SHMT and TPase recombinant vector and dual-enzymatic synthesis of L-tryptophan / 生物工程学报
Chinese Journal of Biotechnology
;
(12): 1302-1308, 2010.
Artículo
en Chino
| WPRIM
| ID: wpr-351592
ABSTRACT
Hydroxymethyltransferase (SHMT) and tryptophanase (TPase) are key enzymes in biosynthesis of L-tryptophan. We constructed three recombinant plasmids, including pET-SHMT, pET-TPase, and pET-ST for over-expression or co-expression of SHMT and TPase in Escherichia coli BL21 (DE3). The SDS-PAGE analysis showed that the recombinant proteins of 47 kDa and 50 kDa were expressed of pET-SHMT and pET-TPase, respectively. As compared to the host stain, the enzyme activity of SHMT and TPase was increased by 6.4 and 8.4 folds, respectively. Co-expression of both recombinant proteins, 47 kDa and 50 kDa, was also successful by using pET-ST and the enzyme activities were enhanced by 6.1 and 6.9 folds. We designed two pathways of dual-enzymatic synthesis of L-tryptophan by using these recombinant strains as source of SHMT and TPase. In the first pathway, the pET-SHMT carrying strain was used to catalyze synthesis of L-serine, which was further transformed into L-tryptophan by the pET-TPase expressing strain. These two steps sequentially took place in different bioreactors. In the second pathway, the pET-ST carrying strain, in which two enzymes were co-expressed, was used to catalyze simultaneously two steps in a single bioreactor. HPLC analysis indicated a high yield of 41.5 g/L of L-tryptophan was achieved in the first pathway, while a lower yield of 28.9 g/L was observed in the second pathway. In the first pathway, the calculated conversion rates for L-glycine and indole were 83.3% and 92.5%, respectively. In the second pathway, a comparable conversion rate, 82.7%, was achieved for L-glycine, while conversion of indole was much lower, only 82.9%.
Texto completo:
Disponible
Índice:
WPRIM (Pacífico Occidental)
Asunto principal:
Farmacología
/
Fisiología
/
Plásmidos
/
Recombinación Genética
/
Glicina Hidroximetiltransferasa
/
Triptófano
/
Triptofanasa
/
Proteínas Recombinantes de Fusión
/
Regulación Bacteriana de la Expresión Génica
/
Regulación Enzimológica de la Expresión Génica
Idioma:
Chino
Revista:
Chinese Journal of Biotechnology
Año:
2010
Tipo del documento:
Artículo
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