PMID:8895467

Citation	Li, YM, Milne, JC, Madison, LL, Kolter, R and Walsh, CT (1996) From peptide precursors to oxazole and thiazole-containing peptide antibiotics: microcin B17 synthase. Science 274:1188-93
Abstract	Esherichia coli microcin B17 is a posttranslationally modified peptide that inhibits bacterial DNA gyrase. It contains four oxazole and four thiazole rings and is representative of a broad class of pharmaceutically important natural products with five-membered heterocycles derived from peptide precursors. An in vitro assay was developed to detect heterocycle formation, and an enzyme complex, microcin B17 synthase, was purified and found to contain three proteins, McbB, McbC, and McbD, that convert 14 residues into the eight mono- and bisheterocyclic moieties in vitro that confer antibiotic activity on mature microcin B17. These enzymatic reactions alter the peptide backbone connectivity. The propeptide region of premicrocin is the major recognition determinant for binding and downstream heterocycle formation by microcin B17 synthase. A general pathway for the enzymatic biosynthesis of these heterocycles is formulated.
Links	PubMed
Keywords	Adenosine Triphosphate/metabolism; Anti-Bacterial Agents/biosynthesis; Anti-Bacterial Agents/chemistry; Anti-Bacterial Agents/pharmacology; Bacterial Proteins; Bacteriocins/biosynthesis; Bacteriocins/chemistry; Bacteriocins/genetics; Bacteriocins/pharmacology; Enzyme Inhibitors/pharmacology; Escherichia coli/enzymology; Escherichia coli/genetics; Molecular Weight; Multienzyme Complexes/genetics; Multienzyme Complexes/isolation & purification; Multienzyme Complexes/metabolism; Operon; Oxazoles/analysis; Oxidation-Reduction; Oxygen/metabolism; Protein Precursors/biosynthesis; Protein Precursors/genetics; Protein Processing, Post-Translational; Substrate Specificity; Thiazoles/analysis; Topoisomerase II Inhibitors
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ECOLX:MCBC		GO:0018130: heterocycle biosynthetic process	ECO:0000314:		P		Figure 5: This figure details the results of a mass spectrometric analysis of a peptide precursor exposed to the trimer including McbC. The precursor lost 40 mass units, the expected amount lost in the formation of 2 heterocycles. In addition, the newly modified peptide was recognized by polyclonal antibodies known to recognize products containing heterocycles.	complete
ECOLX:MCBB		GO:0018130: heterocycle biosynthetic process	ECO:0000314:		P		Figure 5: This figure details the results of a mass spectrometric analysis of a peptide precursor exposed to the trimer including McbB. The precursor lost 40 mass units, the expected amount lost in the formation of 2 heterocycles. In addition, the newly modified peptide was recognized by polyclonal antibodies known to recognize products containing heterocycles.	complete
ECOLX:MCBD		GO:0018130: heterocycle biosynthetic process	ECO:0000314:		P		Figure 5: This figure details the results of a mass spectrometric analysis of a peptide precursor exposed to the trimer including McbD. The precursor lost 40 mass units, the expected amount lost in the formation of 2 heterocycles. In addition, the newly modified peptide was recognized by polyclonal antibodies known to recognize products containing heterocycles.	complete
ECOLX:MCBA		GO:0018130: heterocycle biosynthetic process	ECO:0000314:		P		Figure 5: This figure details the results of a mass spectrometric analysis of a McbA exposed to a trimer of McbBCD. The precursor lost 40 mass units, the expected amount lost in the formation of 2 heterocycles. In addition, the newly modified peptide was recognized by polyclonal antibodies known to recognize products containing heterocycles.	complete

References

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