Cloning and characterization of a gene required for the secretion of extracellular enzymes across the outer membrane by Xanthomonas campestris pv. campestris

Abstract

In gram-negative bacteria, the extracellular proteins have two lipid bilayers to cross, in contrast to the proteins targeted to the periplasm or the outer membrane. Depending upon the secretion route and the genes involved, two major secretion pathways can be identified. Without traversing the periplasm, oc-hemolysin of Escherichia coli is secreted through a hemolysin translocator composed of HlyB, HlyD (24), and ToiC (48). Two genes, prtD and prtE, required for the secretion of an extracellular protease by Erwinia chrysanthemi were found to be homologous to hlyB and hlyD, respectively (27). In the second category, extracellular proteins, for example, the pullulanase of Klebsiella oxytoca, are secreted via the periplasm (34). A closely linked operon includes at least 12 pul genes encoding proteins required for the secretion of pullulanase in addition to the sec genes involved in the translocation of proteins across the inner membrane (34, 35). Homologs of the pul genes are also required for the secretion of extracellular proteins by E. chrysanthemi (22), Pseudomonas aeruginosa (15), Xanthomonas campestns pv. campestris (12), and Yersinia enterocolitica (29). Mutations in these genes can result in the accumulation of extracellular proteins in the periplasm (1,7,11,16,29,34,45,49

Molecular cloning, characterization and nucleotide sequence of the gene for secreted -amylase from Xanthomonas campestris pv. campestris

“…campestris have been isolated by Dow et al (1987) and from our laboratory (Hu et al, 1992). Accumulation of a-amylase in the periplasm was observed in these mutants (Dow et al, 1987 ;Hu et al, 1992), suggesting that a-amylase may be exported via the periplasm. In this study, the gene encoding the a-amylase (amy) of X .…”

Common components in the assembly of type 4 fimbriae, DNA transfer systems, filamentous phage and protein‐secretion apparatus: a general system for the formation of surface‐associated protein complexes

“…These include Erwinia species (secretion of enzymes which degrade the plant cell wall) (He et al, 1991;~ondemine et al, 1992;Lindeberg and eollmer, 1992;Reeves et al, 1993), Xanthomonas campestris (secretion of a range of extracellular enzymes, including pectate Iyases and cellulases) (Dums et al, 1991, Hu et al, 1992, and the opportunistic animal pathogens Aeromonas hydrophila (secretion of the toxin aerolysin and other proteins) (Jiang and Howard , 1992) and P. aeruginosa (secretion of numerous proteins, including elastase, alkaline phosphatase, phospholipase e, and exotoxin A) (Lazdunski et al, 1990;Bally et al, 1991 ;Filloux et al, 1991 ;Nunn and Lory, 1992;Tommassen et al, 1992: Akrim et aI., 1993. Recently it has been shown (Sandkvist et al, 1993) that secretion of cholera toxin by V. cholerae requires a gene, epsE, which is a homologue of pulE (Martin et al, 1993).…”

XpsD, an Outer Membrane Protein Required for Protein Secretion by Xanthomonas campestris pv. campestris, Forms a Multimer

“…campestris required for the secretion of extracellular proteins with a cleavable NH 2 -terminal signal peptide (1)(2)(3). It is likely to be involved in the second step of a two-step secretory pathway, the type II pathway (4 -6).…”

“…XpsD is an outer membrane (OM) 1 protein of Xanthomonas campestris pv. campestris required for the secretion of extracellular proteins with a cleavable NH 2 -terminal signal peptide (1)(2)(3).…”