Characterizing the Roles of AgmT, a Putative Lytic Transglycolyase, in the Gliding Motility of Myxococcus xanthus

Abstract

The gram-negative bacterium Myxcoccus xanthus glides on solid surfaces utilizing an inner-membrane proton channel as the motor. Together with other accessory proteins, motor units form static complexes that exert force between internal helical tracks and the substratum and drive a corkscrew-like motion of the tracks. As a result, the cell also moves forward like a corkscrew. After transient stalls, static complexes quickly disassemble and resume rapid motion. However, is not clear how the mechanical force transmits to cell surfaces across the rigid peptidoglycan (PG) cell wall. Here we show that AgmT, a putative lytic transglycosylase for PG, is an essential component of the gliding machinery. Using single-molecule microscopy, we found that the motors move normally in the absence of AgmT but fail to stall. Thus, we have identified the connection between the gliding motor and the PG. The aim of my research is to investigate how AgmT interacts with PG and if its transglycosylase activity is required for gliding. The findings of this project will reveal the mechanism by which M. xanthus transmits proton motive force from the inner-membrane to the cell surface.