@article {2624, title = {Chemically Induced Cell Wall Stapling in Bacteria.}, journal = {Cell Chem Biol}, volume = {28}, year = {2021}, month = {2021 Feb 18}, pages = {213-220.e4}, abstract = {

Transpeptidation reinforces the structure of cell-wall peptidoglycan, an extracellular heteropolymer that protects bacteria from osmotic lysis. The clinical success of transpeptidase-inhibiting \β-lactam antibiotics illustrates the essentiality of these cross-linkages for cell-wall integrity, but the presence of multiple, seemingly redundant transpeptidases in many species makes it challenging to determine cross-link function. Here, we present a technique to link peptide strands by chemical rather than enzymatic reaction. We employ biocompatible click chemistry to induce triazole formation between azido- and alkynyl-d-alanine residues that are metabolically installed in the peptidoglycan of Gram-positive or Gram-negative bacteria. Synthetic triazole cross-links can be visualized using azidocoumarin-d-alanine, an amino acid derivative that undergoes fluorescent enhancement upon reaction with terminal alkynes. Cell-wall stapling protects Escherichia coli from treatment with the broad-spectrum \β-lactams ampicillin and carbenicillin. Chemical control of cell-wall structure in live bacteria can provide functional insights that are orthogonal to those obtained by genetics.

}, issn = {2451-9448}, doi = {10.1016/j.chembiol.2020.11.006}, author = {Rivera, Sylvia L and Espaillat, Akbar and Aditham, Arjun K and Shieh, Peyton and Muriel-Mundo, Chris and Kim, Justin and Cava, Felipe and Siegrist, M Sloan} } @article {1503, title = {Host Actin Polymerization Tunes the Cell Division Cycle of an Intracellular Pathogen.}, journal = {Cell Rep}, year = {2015}, month = {2015 Apr 15}, abstract = {

Growth and division are two of the most fundamental capabilities of a bacterial cell. While they are well described for model organisms growing in broth culture, very little is known about the cell division cycle of bacteria replicating in more complex environments. Using a D-alanine reporter strategy, we found that intracellular Listeria monocytogenes (Lm) spend a smaller proportion of their cell cycle dividing compared to Lm growing in broth culture. This alteration to the cell division cycle is independent of bacterial doubling time. Instead, polymerization of host-derived actin at the bacterial cell surface extends the non-dividing elongation period and compresses the division period. By decreasing the relative proportion of dividing Lm, actin polymerization biases the population toward cells with the highest propensity to form actin tails. Thus, there is a positive-feedback loop between the Lm cell division\ cycle and a physical interaction with the host cytoskeleton.

}, issn = {2211-1247}, doi = {10.1016/j.celrep.2015.03.046}, author = {Siegrist, M Sloan and Aditham, Arjun K and Espaillat, Akbar and Cameron, Todd A and Whiteside, Sarah A and Cava, Felipe and Portnoy, Daniel A and Bertozzi, Carolyn R} } @article {1445, title = {(D)-Amino acid chemical reporters reveal peptidoglycan dynamics of an intracellular pathogen.}, journal = {ACS Chem Biol}, volume = {8}, year = {2013}, month = {2013 Mar 15}, pages = {500-5}, abstract = {

Peptidoglycan (PG) is an essential component of the bacterial cell wall. Although experiments with organisms in vitro have yielded a wealth of information on PG synthesis and maturation, it is unclear how these studies translate to bacteria replicating within host cells. We report a chemical approach for probing PG in vivo via metabolic labeling and bioorthogonal chemistry. A wide variety of bacterial species incorporated azide and alkyne-functionalized d-alanine into their cell walls, which we visualized by covalent reaction with click chemistry probes. The d-alanine analogues were specifically incorporated into nascent PG of the intracellular pathogen Listeria monocytogenes both in vitro and during macrophage infection. Metabolic incorporation of d-alanine derivatives and click chemistry detection constitute a facile, modular platform that facilitates unprecedented spatial and temporal resolution of PG dynamics in vivo.

}, keywords = {Alanine, Click Chemistry, Listeria monocytogenes, Molecular Conformation, Molecular Dynamics Simulation, Peptidoglycan}, issn = {1554-8937}, doi = {10.1021/cb3004995}, author = {Siegrist, M Sloan and Whiteside, Sarah and Jewett, John C and Aditham, Arjun and Cava, Felipe and Bertozzi, Carolyn R} }