Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.31.1 (micrococcal nuclease)
 2,818 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The staphylococcal nuclease (nuc) gene from Staphylococcus aureus has been cloned and expressed in Bacillus subtilis. The nuclease protein was expressed either from its own promoter and translation start signals, or from a combination of a B. subtilis promoter, ribosome binding site, and a signal peptide sequence. Greater than 80% of the active gene product was secreted into the medium, whereas, when a signal peptide sequence was absent, as little as 4% of the nuclease activity was found in the culture medium. Intracellular (or cell-bound) nuclease, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting, was shown to have the molecular weight of the predicted precursor protein with the signal peptide. Levels of nuclease reached 50 mg per liter in the culture medium, depending on the growth medium and the strain used. These findings indicate the prospective use of nuclease as a model system for studying secretion of heterologous proteins in B. subtilis.
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PMID:Secretion of staphylococcal nuclease by Bacillus subtilis. 392 23

In addition to Gag, Pol, and Env, primate lentiviruses encode other virion-associated proteins, including Vpr, Vpx, and Vif. Vpr- and Vpx-staphylococcal nuclease and chloramphenicol acetyltransferase fusion proteins incorporate into human immunodeficiency virus (HIV) virions and retain enzyme activity when expressed in trans with HIV proviruses (Wu et al., J. Virol. 69, 3389, 1995). To explore whether the viral protease (PR) could be expressed as a proteolytically active fusion protein, the HIV PR coding region was fused in-frame with the HIV-2 vpx and HIV-1 vpr genes. Using a vaccinia virus-T7 expression system, the Vpx-PR fusion protein was expressed and formed homodimers. Coexpression with Pr55Gag demonstrated that Vpx-PR possessed Gag-specific proteolytic activity and inhibited the production of Gag virus-like particles. Trans-expression of a PR-Vpr fusion protein with HIV-1 provirus caused a profound reduction in viral protein expression and virion production. Importantly, the PR-Vpr fusion protein caused a similar level of inhibition and intracellular cleavage of Pr55Gag precursor protein when coexpressed with protease defective HIV-1 provirus. The inhibitory effect of PR-Vpr expression on virion production was markedly greater than that of PR alone. These results indicate that Vpr arguments the intracellular proteolytic activity of PR when expressed as a fusion protein and thus may be relevant for the expression of PR in intracellular immunization strategies against HIV infection. Moreover, the ability to express and package enzymatically active PR-Vpr fusion protein, independent of Gag/Pol, may provide a novel means to study enzyme function.
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PMID:Proteolytic activity of human immunodeficiency virus Vpr- and Vpx-protease fusion proteins. 862 47