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)

We have studied the secretion and processing of Staphylococcus aureus nuclease in Bacillus subtilis. We show that the initial species of nuclease found in the cell supernatants during short-term radioactive labeling (pulse-chase) had a molecular weight of approximately 18,800 and comigrated in a sodium dodecyl sulfate-polyacrylamide gel with staphylococcal nuclease B. This nuclease B form was processed to the mature nuclease A extracellularly by a phenylmethylsulfonyl fluoride-sensitive protease. The nuclease B-processing site is a consensus signal peptidase site, and the processing of nuclease B was coupled to secretion as judged by pulse-chase experiments. The nuclease A was shown by microsequencing of the N terminus to be 2 amino acid residues shorter than the nuclease A described for S. aureus Foggi. The nuclease B form was still the first species found in the culture supernatant after removal of the N-terminal 26 amino acids of the native 60-amino-acid signal peptide. However, removal of the N-terminal 72 amino acids abolishes secretion of any nuclease form and leads to the intracellular accumulation of nuclease.
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PMID:Secretion and processing of staphylococcal nuclease by Bacillus subtilis. 311 23

We have previously used Tn917 for the identification and characterization of regulated promoters from Lactococcus lactis [Israelsen et al., Appl. Environ. Microbiol. 61 (1995) 2540-2547]. We describe here the construction of a new Tn917-transposon derivative, termed TnNuc, which includes the Staphylococcus aureus nuclease gene (nuc) as a reporter for secretion. Transposition of TnNuc into the L. lactis chromosome allows the generation of fusions in-frame with the nuc gene. TnNuc includes also lacZ, a reporter used for identification of relevant clones from the library, i.e. clones with Lac+ phenotype result from transposition of TnNuc into a functional gene on the L. lactis chromosome. The presence of a functional signal sequence at the upstream flanking region of the left repeat of the transposed element results in the detection of nuclease activity using a sensitive plate assay. TnNuc was used for the identification of novel secretion signals from L. lactis. The sequences identified included known and unknown lactococcal-secreted proteins containing either a signal peptidase-I or -II recognition sequence. In one case, the gene identified codes for a transmembrane protein. The sequences identified were used to study functionality when located in a plasmid under the control of the pH and growth phase-dependent promoter P170 [Madsen et al., Mol. Microbiol. 32 (1999) 75-87]. In all cases, concurrent secretion of nuclease was observed during induction of P170 in a fermentor.
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PMID:The development of TnNuc and its use for the isolation of novel secretion signals in Lactococcus lactis. 1072 29