Anionic polymers of Bacillus subtilis cell wall modulate the folding rate of secreted proteins

Abstract

In order to characterize the dynamics of the interaction between the emergent membrane translocated exoprotein and the components of Bacillus subtilis cell wall, we examined the kinetics of the in vitro refolding of levansucrase and alpha-amylase, at pH 7 and 37 degrees C, in the presence of polyphosphates (polyP) of various chain lengths (2</=n</=65). These soluble anionic polymers are considered here to mimic the role of teichoic acids. Even in the absence of calcium, levansucrase rapidly refolded in the presence of polyP of n>/=16. In contrast, polyP modulate indirectly the rate of alpha-amylase refolding via their affinity for calcium. These differential effects might explain that the rate of the cell wall translocation of alpha-amylase secretion was found to be half that of levansucrase.