Investigations on the Role of PatA in the O-Acetylation of Peptidoglycan in Gram-negative Bacteria

The existence of O-acetyl modifications to the C6 hydroxyl of N-acetylmuramic acid residues within the peptidoglycan of bacteria is a contributing factor to their pathogenesis. O-Acetylation in Gram-negative bacteria employs a two-component system of an integral membrane protein, peptidoglycan O-acetyltransferase (Pat) A, and a periplasmic transferase, PatB. The work presented in this study attempted to express patA within an E. coli expression host, while avoiding toxicity complications. Herein, the apparent production of PatA from Proteus mirabilis was achieved as detected by western immunoblot, but the protein’s true identity remains to be confirmed by mass spectrometry. Additionally, the possibility of a periplasmic molecule to mediate the transfer of acetyl groups from PatA to PatB was explored, but inconsistent results prove that a different approach needs to be taken to assess this hypothesis. These results provide a framework for the expression of patA so that it may be characterized in future studies.