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Title
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Overproduction of DnaJ in Escherichia coli improves in vivo solubility of the recombinant fish-derived transglutaminase.
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Authors
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K.Yokoyama,
Y.Kikuchi,
H.Yasueda.
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Ref.
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Biosci Biotechnol Biochem, 1998,
62,
1205-1210.
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PubMed id
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Abstract
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The overexpression of red sea bream (Pagrus major) transglutaminase (TGase, E.C.
2.3.2.13) in Escherichia coli mostly leads to the accumulation of biologically
inactive enzyme. Although the solubility of the gene products could be improved
by cultivation at a lower temperature (26-28 degrees C), most of the synthesized
TGase was still in the form of insoluble aggregates. The effects of
overproduction of molecular chaperones on the intracellular solubility of newly
produced recombinant TGase were examined. The overexpression of dnaK or groES/EL
did not improve solubility. However, DnaJ greatly increased the solubility of
the recombinant TGase, resulting in active enzyme in the presence of calcium
ions. Co-expression of dnaK along with dnaJ further increased the content of
soluble TGase. Under our experimental conditions, supplementation with both DnaJ
and DnaK elevated the TGase activity in the producer cells by roughly 4-fold,
compared with the control strain cultured at 30 degrees C. Thus, we found that
DnaJ is important in controlling the solubility of protein overproduced in E.
coli.
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