Journal Article

A new metabolic cell-wall labelling method reveals peptidoglycan in Chlamydia trachomatis

Liechti, G. W., Kalinda, A., Kuru, E., Hall, E., Maurelli, A. T., VanNieuwenhze, M., Brun, Y. V.

2014

Overview

Peptidoglycan is an essential structural component of the cell wall in the majority of bacteria, but the obligate intracellular human pathogen Chlamydia trachomatis was thought to be one of the few exceptions; here a click chemistry approach is used to label peptidoglycan in replicating C. trachomatis with novel d -amino acid dipeptide probes. The chlamydial anomaly resolved The sugar amino acid polymer peptidoglycan is an essential cell-wall component in most free-living bacteria. The Chlamydiales, Gram-negative parasites including the human pathogen Chlamydia trachomatis , were thought to be a rare exception: they encode genes for peptidoglycan biosynthesis and are susceptible to β -lactam antibiotics, yet attempts to detect chlamydial peptidoglycans had failed. Now this paradox, known as the 'chlamydial anomaly', has been resolved. This study, using a novel click chemistry technique to label peptidoglycans with D -amino acid dipeptide probes, demonstrates the presence of peptidoglycans in replicating C. trachomatis . Peptidoglycan (PG), an essential structure in the cell walls of the vast majority of bacteria, is critical for division and maintaining cell shape and hydrostatic pressure 1 . Bacteria comprising the Chlamydiales were thought to be one of the few exceptions. Chlamydia harbour genes for PG biosynthesis 2 , 3 , 4 , 5 , 6 , 7 and exhibit susceptibility to ‘anti-PG’ antibiotics 8 , 9 , yet attempts to detect PG in any chlamydial species have proven unsuccessful (the ‘chlamydial anomaly’ 10 ). We used a novel approach to metabolically label chlamydial PG using d -amino acid dipeptide probes and click chemistry. Replicating Chlamydia trachomatis were labelled with these probes throughout their biphasic developmental life cycle, and the results of differential probe incorporation experiments conducted in the presence of ampicillin are consistent with the presence of chlamydial PG-modifying enzymes. These findings culminate 50 years of speculation and debate concerning the chlamydial anomaly and are the strongest evidence so far that chlamydial species possess functional PG.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 14/19 / 14/34 / 14/63 / 631/326/1320 / Amino acids / Amino Acids - chemistry / Amino Acids - metabolism / Antibiotics / Bacteria / Bacterial infections / Bacteriology / Biosynthesis / Cell division / Cell research / Cell Wall - chemistry / Cell Wall - metabolism / Chlamydia / Chlamydia trachomatis / Chlamydia trachomatis - chemistry / Chlamydia trachomatis - cytology / Chlamydia trachomatis - drug effects / Chlamydia trachomatis - metabolism / Click Chemistry / Dipeptides - analysis / Dipeptides - chemistry / Enzymes / Fluorescence / Humanities and Social Sciences / Hydrostatic pressure / Intracellular Space - chemistry / Intracellular Space - metabolism / letter / Methods / Molecular Probes - analysis / Molecular Probes - chemistry / multidisciplinary / Peptidoglycan - analysis / Peptidoglycan - biosynthesis / Peptidoglycan - chemistry / Peptidoglycan - metabolism / Peptidoglycans / Physiological aspects / Plant cell walls / Probes / Science / Staining and Labeling - methods