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

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 less than or equal to n less than or equal to 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 greater than or equal to 16. In contrast, polyP modulate indirectly the rate of a-amylase refolding via their affinity for calcium. These differential effects might explain that the rate of the cell wall translocation of oc-amylase secretion was found to be half that of levansucrase. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.