title: The Creatininase Homolog MftE fromMycobacterium smegmatisCatalyzes a Peptide Cleavage Reaction in the Biosynthesis of a Novel Ribosomally Synthesized Post-translationally Modified Peptide (RiPP).
abstract: Most ribosomally synthesized and post-translationally modified peptide (RiPP) natural products are processed by tailoring enzymes to create complex natural products that are still recognizably peptide-based. However, some tailoring enzymes dismantle the peptide en route to synthesis of small molecules. A small molecule natural product of as yet unknown structure, mycofactocin, is thought to be synthesized in this way via themftgene cluster found in many strains of mycobacteria. This cluster harbors at least six genes, which appear to be conserved across species. We have previously shown that one enzyme from this cluster, MftC, catalyzes the oxidative decarboxylation of the C-terminal Tyr of the substrate peptide MftA in a reaction that requires the MftB protein. Herein we show thatmftEencodes a creatininase homolog that catalyzes cleavage of the oxidatively decarboxylated MftA peptide to liberate its final two residues, including the C-terminal decarboxylated Tyr (VY*). Unlike MftC, which requires MftB for function, MftE catalyzes the cleavage reaction in the absence of MftB. The identification of this novel metabolite, VY*, supports the notion that themftcluster is involved in generating a small molecule from the MftA peptide. The ability to produce VY* from MftA byin vitroreconstitution of the activities of MftB, MftC, and MftE sets the stage for identification of the novel metabolite that results from the proteins encoded by themftcluster.
authors.affiliation: From the Department of Chemistry, University of Utah, Salt Lake City, Utah 84112.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Bruender
authors.affiliation: From the Department of Chemistry, University of Utah, Salt Lake City, Utah 84112 vahe@chem.utah.edu.
authors.forename: Vahe
authors.initials: V
authors.lastname: Bandarian
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism*; D002384:Catalysis; D018360:Crystallography, X-Ray; D020102:Mycobacterium smegmatis / Q000254:growth & development / Q000378:metabolism*; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012270:Ribosomes / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D014512:Ureohydrolases / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D010446:Peptide Fragments; D014512:Ureohydrolases; C019944:creatinase
keywords: enzyme catalysis; enzyme mechanism; natural product biosynthesis; proteolytic enzyme; secondary metabolism