title: Studying a cell division amidase using defined peptidoglycan substrates.
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.
authors: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors: Tania J
authors: TJ
authors: Lupoli
authors: Tohru
authors: T
authors: Taniguchi
authors: Tsung-Shing
authors: TS
authors: Wang
authors: Deborah L
authors: DL
authors: Perlstein
authors: Suzanne
authors: S
authors: Walker
authors: Daniel E
authors: DE
authors: Kahne
mesh_terms: D000581:Amidohydrolases / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D002455:Cell Division; D004926:Escherichia coli / Q000166:cytology / Q000201:enzymology; D029968:Escherichia coli Proteins; D008666:Metalloendopeptidases; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D010457:Peptidoglycan / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity; D015032:Zinc
chemical_list: D029968:Escherichia coli Proteins; D010446:Peptide Fragments; D010457:Peptidoglycan; D008666:Metalloendopeptidases; D000581:Amidohydrolases; C019665:amidase; D015032:Zinc