Five new genes are important for common polysaccharide antigen biosynthesis in Pseudomonas aeruginosa.
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The pa5455-pa5459 cluster, adjacent to the CPA locus, is required for CPA biosynthesis.
"Here we demonstrate that an adjacent five-gene cluster pa5455-pa5459 is also involved"
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PA5458 carries a conserved acetyltransferase domain (sequence analysis only).
"The pa5458 gene encodes a protein with a conserved acetyltransferase domain."
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The pa5458 in-frame deletion still produces CPA, but with altered migration and weaker monoclonal antibody binding, i.e. a structurally different polymer.
"Mutation of the putative acetyltransferase-encoding gene pa5458 did not abrogate polysaccharide production"
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The mutant CPA bands are shifted and diffuse.
"When the run time of SDS-PAGE was increased, it was clear that the bands produced by the mutant were shifted relative to the positions of bands produced by the wild type, and the bands also appeared to be more diffuse"
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Authors interpret PA5458 as modifying CPA structure, consistent with reported acetyl substitutions, and not as required for polymer assembly.
"its function is clearly not required for assembly and processing of the polysaccharide, although the mutant produces CPA with a different structure, which is consistent with previous reports of the presence of acetylation substitutions in the sugars of CPA"
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Overexpression modestly reduces CPA amount and chain length.
"Overexpression of the putative acetyltransferase resulted in a modest reduction in the amount of CPA produced and a subtle shift in the chain length distribution"