1887

Abstract

The gene of encodes a periplasmic enzyme which catalyses disulfide bond formation. Analysis of its surrounding DNA region showed that it is preceded by an open reading frame, , of 984 nucleotides. The intergenic region (19 nucleotides) carries no typical transcription termination signals. is transcribed from two promoters, the first (P1) lies in the distal part of , and the second (P2) just upstream from . Using a plasmid-borne :: Tn fusion and an :: ω insertion, each promoter was shown to contribute equally to transcription. The disruption of the single chromosomal copy of by ω more drastically reduced the amount of DsbA in the periplasmic space. Such a reduction of the DsbA pool, however, did not change the activities of the AppA, Agp and PhoA periplasmic phosphatases, which all require disulfide bond formation, even when the enzymes were produced from multicopy recombinant plasmids. Thus, in a wild-type strain, DsbA is far from being in limiting amounts for physiological requirements. The gene product was identified as a weakly expressed 39 kDa cytoplasmic protein, but it is not involved in the overall mechanism of disulfide bond formation.

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/content/journal/micro/10.1099/13500872-140-12-3337
1994-12-01
2019-11-15
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