AlgF is essential for the addition of O-acetyl groups to alginate, an extracellular polysaccharide. The presence of O-acetyl groups plays an important role in the ability of the polymer to act as a virulence factor [1].

1: Mutant analysis and cellular localization of the AlgI, AlgJ, and AlgF proteins required for O acetylation of alginate in Pseudomonas aeruginosa. Franklin MJ, Ohman DE; J Bacteriol. 2002;184:3000-3007. PMID:12003941