The hyperthermophilic α-amylase from Thermococcus sp. HJ21 does not require exogenous calcium for thermostability because of high-binding affinity to calcium.
J Microbiol
; 55(5): 379-387, 2017 May.
Article
em En
| MEDLINE
| ID: mdl-28251549
ABSTRACT
The hyperthermophilic α-amylase from Thermococcus sp. HJ21 does not require exogenous calcium ions for thermostability, and is a promising alternative to commercially available α-amylases to increase the efficiency of industrial processes like the liquefaction of starch. We analyzed the amino acid sequence of this α-amylase by sequence alignments and structural modeling, and found that this α-amylase closely resembles the α-amylase from Pyrococcus woesei. The gene of this α-amylase was cloned in Escherichia coli and the recombinant α-amylase was overexpressed and purified with a combined renaturation-purification procedure. We confirmed thermostability and exogenous calcium ion independency of the recombinant α-amylase and further investigated the mechanism of the independency using biochemical approaches. The results suggested that the α-amylase has a high calcium ion binding affinity that traps a calcium ion that would not dissociate at high temperatures, providing a direct explanation as to why the addition of calcium ions is not required for thermostability. Understanding of the mechanism offers a strong base on which to further engineer properties of this α-amylase for better potential applications in industrial processes.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Cálcio
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Thermococcus
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Alfa-Amilases
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article