Article Abstract:
The recombinant beta subunit of a molecular chaperonin (CpkB), heat shock proteins, from the hyperthermophilic archaeon Pyrococcus sp. strain KOD1 prevents thermal denaturation, and enhances the thermostability of alcohol dehydrogenase in Escherichia coli. The coexpression of CpkB and cobryic acid synthase dissolves insoluble proteins in vivo. ATP is necessary for the activity of CpkB if the CpkB level is low, and unnecessary if the level is high. Thus, the beta subunit plays an important role in the activity of chaperonin and is functional without the alpha subunit.
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Article Abstract:
The glnA gene encoding glutamine synthetase was cloned from the hyperthermophilic archaeon Pyrococcus sp. strain KOD1 and its nucleotide sequence was determined. The glnA gene was expressed in Escherichia coli ME8459 and the protein was purified to homogeneity and found to be functional in a dodecameric form, showing both transferase and synthetase activities. However, the enzyme had low biosynthetic activity, indicating that the reaction was biased towards glutamate production.
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Article Abstract:
The identification of protein regions necessary for cyclization activity using constructed and characterized chimeric enzymes is discussed. The cyclodextrin production and thermostability of these chimeric enzymes were examined using nucleotide sequence analysis and base substitutions. It was found that the NH2-terminal region of the cyclodextrin glucanotransferase provided the cyclization reaction.
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