Disulfide oxidoreductase activity of Shigella flexneri is required for release of Ipa proteins and invasion of epithelial cells.

• DOI: 10.1073/pnas.92.11.4927
• Publication Date: 2006-05-31T13:11:38Z
• Authors: M Watarai; T Tobe; M Yoshikawa; C Sasakawa
• Keywords: DsbA

Secretion of IpaB, IpaC, and IpaD proteins Shigella flexneri, essential for the invasion epithelial cells, requires a number encoded by spa mxi loci on large plasmid. Introduction dsbA::Tn5 into S.flexneri from Escherichia coli K-12 reduced invasiveness, which resulted decrease in capacity to release external medium. Examination surface-presented Ipa dsbA mutant, however, revealed at levels similar those wild-type cells. Since defective phenotype was that spa32 mutant S. flexneri Spa32 sequence possessed two Cys residues, effect mutation folding structure under reducing conditions surface expression investigated. The results indicated disulfide-containing protein whose correctly folded required its presentation outer membrane. Indeed, replacing either one residues with Ser site-directed mutagenesis medium led accumulation periplasm. These DsbA performs an function during mammalian facilitating transport across