Guojun Zheng

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The formation of inclusion bodies (IBs) in recombinant protein biotechnology has become one of the most frequent undesirable occurrences in both research and industrial applications. So far, the pET System is the most powerful system developed for the production of recombinant proteins when Escherichia coli is used as the microbial cell factory. Also, using(More)
Biocatalyzed synthesis of nucleoside analogues was carried out using two thermostable nucleoside phosphorylases from the hyperthermophilic aerobic crenarchaeon Aeropyrum pernix K1. The synthesis of the 2,6-diaminopurine nucleoside and 5-methyluridine was used as a reaction model to test the process. Both the purine nucleoside phosphorylase (apPNP) and(More)
2-Azabicyclo[2.2.1]hept-5-en-3-one (γ-lactam) is an important precursor of many carbocyclic nucleoside analogs and pharmaceuticals. (−)-γ-Lactam has attracted much attention because of its role as an intermediate of antiviral drugs such as abacavir and carbovir. (+)-γ-Lactamase can be used for the kinetic resolution of γ-lactam to obtain (−)-γ-lactam. In(More)
A (−)γ-lactamase, Mhg, from Microbacterium hydrocarbonoxydans was over-expressed in E. coli and was characterized after purification. The maximum activity was at pH 8.0 and 60°C and the half life of Mhg was ~30 min at 75°C. The enzyme was activated by DTT. The catalytic triad of the (−)γ-lactamase is comprised of residues Ser98, Asp230, and His259 and an(More)
Five truncated constructs of Xcc_est GDSL esterase from Xanthomonas campestris were heterologously expressed and purified. The truncated constructs with a RGD motif had higher specific activities than those without the motif. The specific activity of wild-type Xcc_est was 32.5 +/- 2.7 U/mg, while the RGD mutant was 12.5 +/- 4.9 U/mg. Moreover, we expressed(More)
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