The dsbB Gene Product Is Required for Protease Production by Burkholderia cepacia

Burkholderia(formerly Pseudomonas) cepacia is a causative agent of severe pulmonary infection in immunocompromised patients. We have found that B. cepacia strain KF1, isolated from a pneumoniae patient, produces a 37kDa extracellular metalloprotease in larger quantities than the other clinical and environmental isolates. To study the mechanism of protease production, we constructed protease-negative mutants using a transposon mutagenesis. One of the mutant, KFTI007, protease-deficient and lipase-proficient mutant, was complemented by a clone having an open reading frame coding for a 170-amino-acid polypeptide, which showed significant homology to Escherichia coli DsbB. KFTI007, presumed dsbB mutant, also failed to show motility, and both protease secretion and motility were restored by the introduction of the cloned dsbB gene of B. cepacia. The mutant KFTI007 excreted a 43kDa polypeptide that is immunologically related to the 37kDa mature protease. These results suggest that the dsbB mutant secretes a premature and catalytically inactive form of protease and that disulfide formation is required for the production of extracellular protease by B. cepacia.

B.cepacia

金属プロテアーゼ

DsbA

DsbB

disulfide bond oxidoreductase