Three-dimensional structures of Pseudomonas aeruginosa PvcA and PvcB, two proteins involved in the synthesis of 2-isocyano-6,7-dihydroxycoumarin.
The pvcABCD operon of Pseudomonas aeruginosa encodes four proteins (PA2254, PA2255, PA2256, and PA2257) that form a cluster that is responsible for the synthesis of a cyclized isocyano derivative of tyrosine. These proteins, which were identified originally as being responsible for a step in the maturation of the chromophore of the peptide siderophore pyoverdine, have been identified recently as belonging to a family of proteins that produce small organic isonitriles. We report that strains harboring a disruption in the pvcA or pvcB genes are able to grow in iron-depleted conditions and to produce pyoverdine. Additionally, we have determined the three-dimensional crystal structures of PvcA and PvcB. The structure of PvcA demonstrates a novel enzyme architecture that is built upon a Rossmann fold. We have analyzed the sequence conservation of enzymes within this family and identified six conserved motifs. These regions of the protein cluster around a putative active site cavity. The structure of the PvcB protein confirms it is a member of the Fe2+/alpha-ketoglutarate-dependent oxygenase family of enzymes. The active site of PvcB is compared to the structures of other family members and suggests that a conformational change to order several loops will accompany the binding of ligands.
Drake
Eric J
EJ
Hauptman-Woodward Medical Research Institute, Department of Structural Biology, State University of New York at Buffalo, 700 Ellicott St, Buffalo, NY 14203-1102, USA.
Gulick
Andrew M
AM
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D049109:Cell Proliferation / Q000187:drug effects; D017124:Conserved Sequence; D003374:Coumarins / Q000737:chemistry / Q000378:metabolism*; D018360:Crystallography, X-Ray; D003470:Culture Media; D007502:Iron Chelating Agents / Q000494:pharmacology; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009842:Oligopeptides / Q000096:biosynthesis; D009876:Operon / Q000235:genetics; D017433:Protein Structure, Secondary; D011550:Pseudomonas aeruginosa / Q000737:chemistry* / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D016415:Sequence Alignment; D055672:Static Electricity
C532942:2-isocyano-6,7-dihydroxycoumarin; D001426:Bacterial Proteins; D003374:Coumarins; D003470:Culture Media; D007502:Iron Chelating Agents; D009842:Oligopeptides; C042453:pyoverdin