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Cloning and nucleotide sequence of the signal peptidase II (lsp)-gene from Staphylococcus carnosus
Abstract:
Staphylococcus carnosus TM300 is able to synthesize at least seven lipoproteins with molecular masses between 15 and 45 kDa; the proteins are located in the membrane fraction. It can be concluded that this strain also posesses the enzymes involved in lipoprotein modification and prolipoprotein signal peptidase (signal peptidase II) processing. The gene encoding the prolipoprotein signal peptidase, lsp, from Staphylococcus carnosus TM300 was cloned in Escherichia coli and sequenced. The deduced amino acid sequence of the Lsp showed amino acid similarities with the Lsp's of S. aureus, Enterobacter aerogenes, E. coli, and Pseudomonas fluorescens. The hydropathy profile reveals four hydrophobic segments which are homologous to the putative transmembrane regions of the E. coli signal peptidase II. E. coli strains carrying lsp of S. carnosus exhibited an increased globomycin resistance.
Insights
Staphylococcus carnosus synthesizes multiple lipoproteins. Researchers cloned and sequenced the prolipoprotein signal peptidase (lsp) gene, finding similarities to other bacteria and increased globomycin resistance in E. coli.
Area of Science:
- Microbiology
- Molecular Biology
- Protein Biochemistry
Background:
- Staphylococcus carnosus TM300 synthesizes at least seven lipoproteins (15-45 kDa) localized in the membrane fraction.
- This suggests the strain possesses enzymes for lipoprotein modification and prolipoprotein signal peptidase (signal peptidase II) processing.
Purpose of the Study:
- To clone and sequence the prolipoprotein signal peptidase (lsp) gene from Staphylococcus carnosus TM300.
- To analyze the deduced amino acid sequence and compare it with known Lsp proteins.
- To investigate the functional implications of the cloned gene in a heterologous host.
Main Methods:
- Gene cloning of Staphylococcus carnosus TM300 lsp in Escherichia coli.
- DNA sequencing of the cloned lsp gene.
- Amino acid sequence analysis and hydropathy profiling.
- Phenotypic analysis of E. coli transformants for globomycin resistance.
Main Results:
- The lsp gene from S. carnosus TM300 was successfully cloned and sequenced.
- The deduced Lsp amino acid sequence showed homology to Lsp proteins from S. aureus, E. aerogenes, E. coli, and P. fluorescens.
- Hydropathy profiling indicated four hydrophobic segments homologous to E. coli signal peptidase II transmembrane regions.
- E. coli strains harboring the S. carnosus lsp gene exhibited enhanced resistance to globomycin.
Conclusions:
- The cloned Staphylococcus carnosus lsp gene encodes a functional prolipoprotein signal peptidase.
- The S. carnosus Lsp shares structural and functional similarities with signal peptidase II from other bacterial species.
- The increased globomycin resistance in E. coli transformants highlights the functional conservation and potential applications of the S. carnosus lsp gene.