Use of Bioorthogonal N‐Acetylcysteamine (SNAc) Analogues and Peptidoglycan O‐Acetyltransferase B (PatB) to Label Peptidoglycan

Abstract

In Gram (−) bacteria, peptidoglycan O‐acetyltransferase B (PatB) is responsible for the O‐acetylation of peptidoglycan to prevent degradation by lysozyme and other lytic transglycosylases generated by its host. In this work, PatB was exploited as a tool to incorporate bioorthogonal functionality on the carbohydrate backbone of the peptidoglycan by using a variety of donors, either p‐nitrophenol (pNP) or N‐acetylcysteamine (SNAc). Using tri‐N‐acetylglucosamine (GlcNAc)3 as a peptidoglycan mimic, a variety of functionalities were installed, including an alkyne and azide handle, on this mimic. Further studies in vitro showed that these modifications have a protective effect on isolated peptidoglycan from B. subtilis, E. coli, P. putida, and V. parahaemolyticus against lysozyme degradation. Intrigued by these results, an alkyne handle was subsequently installed on whole bacterial cells of B. subtilis using the SNAc alkyne derivative and the carbohydrate backbone was fluorescently labeled via click chemistry. Altering the peptidoglycan post‐synthetically with these derivatives will aid in the isolation and identification of immune stimulatory fragments from bacteria, as well as in the development of antibiotics and immune modulators.Support or Funding InformationThe Delaware COBRE and INBRE programs supported this project with a grant from the NIGMS (5 P30GM110758‐02, P20GM104316‐01A1 and P20GM103446) from the NIH.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.