Studying a cell division amidase using defined peptidoglycan substrates
Journal
Journal of the American Chemical Society
Journal Volume
131
Journal Issue
51
Pages
18230-18231
Date Issued
2009
Author(s)
Abstract
Three periplasmic N-acetylmuramoyl-l-alanine amidases are critical for hydrolysis of septal peptidoglycan, which enables cell separation. The amidases cleave the amide bond between the lactyl group of muramic acid and the amino group of l-alanine to release a peptide moiety. Cell division amidases remain largely uncharacterized because substrates suitable for studying them have not been available. Here we have used synthetic peptidoglycan fragments of defined composition to characterize the catalytic activity and substrate specificity of the important Escherichia coli cell division amidase AmiA. We show that AmiA is a zinc metalloprotease that requires at least a tetrasaccharide glycopeptide substrate for cleavage. The approach outlined here can be applied to many other cell wall hydrolases and should enable more detailed studies of accessory proteins proposed to regulate amidase activity in cells.
Type
journal article