alg8

Summary: Alg8 synthesizes the specific polysaccharide alginate.

Reason: Refine the true general polysaccharide-biosynthesis term to its alginate-biosynthesis descendant, already present in this review.

Proposed replacements: alginic acid biosynthetic process

Summary: Alg8 is an inner-membrane glycosyltransferase.

Reason: PhoA topology experiments support membrane anchoring and a cytoplasmic catalytic region; the bacterial inner membrane is the plasma membrane.

Summary: Alg8 is an inner-membrane glycosyltransferase.

Reason: PhoA topology experiments support membrane anchoring and a cytoplasmic catalytic region; the bacterial inner membrane is the plasma membrane.

Summary: Alg8 makes mannuronan, not hyaluronan.

Reason: The IBA at PANTHER:PTN000530809 crosses substrate specificity within a glycosyltransferase family. Alg8 uses GDP-mannuronate for alginate; hyaluronan synthesis instead alternates glucuronate and N-acetylglucosamine. Target-specific mutagenesis and polymerization evidence contradict this substrate assignment. This challenges propagation scope, not donor count or the target appearing among donors.

Summary: Alg8 catalyzes mannuronan polymerization in alginate synthesis.

Reason: Alg8 active-site substitutions, loss/complementation genetics and cell-envelope polymerization assays support its processive glycosyltransferase role. These data do not imply isolated Alg8 alone reconstitutes the secretion machinery.

Summary: Alg8 catalyzes mannuronan polymerization in alginate synthesis.

Reason: Alg8 active-site substitutions, loss/complementation genetics and cell-envelope polymerization assays support its processive glycosyltransferase role. These data do not imply isolated Alg8 alone reconstitutes the secretion machinery. PseudoCAP seed assessment (2026-11-05): this row is the PAO1 seed of the GO:0000271 IBD at PTN000530809. Verdict SOUND. The abstract states that alg8 mutants make no polymer and that each predicted active-site residue is required for polymerization in vivo, so the gene's own catalytic role, not only a phenotype, is shown. The IBD also stands on the three mouse hyaluronan synthase seeds.

Summary: Alg8 catalyzes mannuronan polymerization in alginate synthesis.

Reason: Alg8 active-site substitutions, loss/complementation genetics and cell-envelope polymerization assays support its processive glycosyltransferase role. These data do not imply isolated Alg8 alone reconstitutes the secretion machinery.

Summary: Alg8 makes mannuronan, not hyaluronan.

Reason: The IBA at PANTHER:PTN000530809 crosses substrate specificity within a glycosyltransferase family. Alg8 uses GDP-mannuronate for alginate; hyaluronan synthesis instead alternates glucuronate and N-acetylglucosamine. Target-specific mutagenesis and polymerization evidence contradict this substrate assignment. This challenges propagation scope, not donor count or the target appearing among donors.

Summary: Alg8 constructs the alginate matrix polymer and contributes to architecture of alginate-producing biofilms.

Reason: Alg8 directly polymerizes a structural extracellular-matrix polysaccharide. In the native P. aeruginosa PDO300 background, alg8 complementation restores highly structured biofilms relative to the nonmucoid deletion control (PMID:25968647, Fig. 9 and Table 2). The matrix-assembly role is therefore supported by target-specific architecture measurements together with demonstrated polymer synthesis, rather than necessity alone. Retain this conditional biofilm role as non-core; alginate polymerization remains the core activity. This evidence supports the broad biological claim independently of the unresolved PAINT node placement. GO:0085029 concerns aggregation, arrangement and bonding of extracellular matrix without a mammalian restriction. The architecture data and polymer-building mechanism support this conditional matrix role. GO:0044010 describes the distinct whole-biofilm process rather than a more specific replacement for this assembly claim; no additional biofilm annotation is proposed.