Functional analysis of the propeptides of subtilisin E and aqualysin I as intramolecular chaperones

Several proteases require propeptides for the correct folding of their own protease domain. We have recently found that the propeptide from a thermost able subtilisin homolog aqualysin I can refold subtilisin BPN' when added i n trans. Here, we constructed chimeric genes with subtilisin E and aqualysi n I to attempt the in cis folding of subtilisin E by means of the propeptid e of aqualysin I. Our results indicate that the propeptide of aqualysin I c an to some extent chaperone the intramolecular folding of the denatured sub tilisin E. These results suggest that propeptides in the subtilisin family, despite their sequence diversity, have similar functions. Further, some en zymatic properties of some chimeras in which the subtilisin mature domain i s partly swapped with that of aqualysin I were shown to be more similar to those of aqualysin I. (C) 2001 Federation of European Biochemical Societies . Published by Elsevier Science B.V. All rights reserved.