Dual function of the O ‐antigen WaaL ligase of Aggregatibacter actinomycetemcomitans

In this study, we have determined that theEscherichia coli waaL ortholog (rflA) does not restore collagen binding of awaaL mutant strain ofA. actinomycetemcomitans but does restore O-PS ligase activity following transformation of a plasmid expressingwaaL. Therefore, a heterologousE. coli expression system was developed constituted of two independently replicating plasmids expressing eitherwaaL oremaA ofA. actinomycetemcomitans to directly demonstrate the necessity of ligase activity for EmaA collagen binding. Proper expression of the protein encoded by each plasmid was characterized, and the individually transformed strains did not promote collagen binding. However, coexpression of the two plasmids resulted in a strain with a significant increase in collagen binding activity and a change in the biochemical properties of the protein. These results provide additional data supporting the novel hypothesis that the WaaL ligase ofA. actinomycetemcomitans shares a dual role as a ligase in LPS biosynthesis and is required for collagen binding activity of EmaA.

Source: Molecular Oral Microbiology - November 9, 2023 Category: Microbiology Authors: David R. Danforth, Marcella Melloni, Richard Thorpe, Avi Cohen, Richard Voogt, Jake Tristano, Keith P. Mintz Tags: ORIGINAL ARTICLE Source Type: research