English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Thewbp cluster ofPseudomonas aeruginosa O5 encodes a number of proteins involved in biosynthesis of the heteropolymeric and Wzy-dependent B-band O antigen, including Wzy, the O-antigen polymerase, and Wzz, the regulator of O-antigen chain length. A gene (formerlywbpF ), contiguous withwzy in thewbp cluster, is predicted to encode a highly hydrophobic protein with multiple membrane-spanning domains. This secondary structure is consistent with that of Wzx (RfbX), the putative O-antigen unit translocase or “flippase.” Insertion of a Gmr cassette at two separate sites within the putativewzx gene led in both cases to the loss of B-band lipopolysaccharide (LPS) O-antigen production. To our knowledge, this is the first report of the successful generation of chromosomalwzx gene replacement mutations. Surprisingly, inactivation ofwzx also led to a marked delay in production of the ATP-binding cassette–transporter-dependent,d -rhamnose homopolymer, A-band LPS. This effect on A-band LPS synthesis was alleviated by supplying multiple copies of WbpL intrans . WbpL, a WecA (Rfe) homologue, was shown recently to be essential for the initiation of both A-band and B-band LPS synthesis inP. aeruginosa O5 (H. L. Rocchetta, L. L. Burrows, J. C. Pacan, and J. S. Lam, Mol. Microbiol. 28:1103–1119, 1998). These results suggest that the delay in A-band LPS production may arise from insufficient access to WbpL when the completed B-band O unit is not successfully translocated to the periplasm. Without adequate WbpL, A-band LPS synthesis is delayed. A subset ofwzx mutants appeared to have accumulated second-site mutations which either restored the normal expression of A-band LPS or abolished A-band expression completely. Complementation studies showed that all of the additional mutations affecting LPS synthesis that were characterized in this study were located within the B-band LPS genes.

Effect of wzx ( rfbX ) Mutations on A-Band and B-Band Lipopolysaccharide Biosynthesis in Pseudomonas aeruginosa O5