Isolation and characterization of an extracellular haem-binding protein from Pseudomonas aeruginosa that shares function and sequence similarities with the Serratia marcescens HasA haemophore.
The major mechanism by which bacteria acquire free or haemoglobin-bound haem involves direct binding to specific outer membrane receptors. Serratia marcescens also secretes a haem-binding protein, HasA, which functions as a haemophore that catches haem and shuttles it to a cell surface specific outer membrane receptor, HasR. We report the isolation and characterization of hasAp, a gene from Pseudomonas aeruginosa. HasAp is an iron-regulated extracellular haem-binding protein that shares about 50% identity with HasA. HasAp is required for P. aeruginosa utilization of haemoglobin iron. It can replace HasA for HasR-dependent haemoblobin acquisition in a system reconstituted in Escherichia coli. HasAp, like HasA, lacks a signal peptide and is secreted by an ABC transporter. These findings show that haemophore-dependent haem acquisition is not unique to S. marcescens.
Létoffé
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Unité de Physiologie Cellulaire Institut Pasteur (CNRS URA 1300), Paris, France.
Redeker
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Wandersman
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D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015139:Blotting, Southern; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism; D006418:Heme / Q000378:metabolism; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D012706:Serratia marcescens / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; C093956:HasA protein, Serratia marcescens; C114820:HasAp protein, Pseudomonas aeruginosa; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D006454:Hemoglobins; D008565:Membrane Proteins; D006418:Heme