The Glycoprotease CpaA Secreted by Medically Relevant Acinetobacter Species Targets Multiple <i>O</i> -Linked Host Glycoproteins

Abstract

CpaA is a glycoprotease expressed by members of the Acinetobacter baumannii-calcoaceticus complex, and it is the first bona fide secreted virulence factor identified in these species. Here, we show that CpaA cleaves multiple targets precisely at O -glycosylation sites preceded by a Pro residue. This feature, together with the observation that sialic acid does not impact CpaA activity, makes this enzyme an attractive tool for the analysis of O -linked human protein for biotechnical and diagnostic purposes. Previous work identified proteins involved in blood coagulation as targets of CpaA. Our work broadens the set of targets of CpaA, pointing toward additional roles in bacterium-host interactions. We propose that CpaA belongs to an expanding class of functionally defined glycoproteases that targets multiple O -linked host glycoproteins.