Utility of bacterial peptidoglycan recycling enzymes in the chemoenzymatic synthesis of valuable UDP sugar substrates

Author(s):  
Ophelia I. Ukaegbu ◽  
Kristen E. DeMeester ◽  
Hai Liang ◽  
Ashley R. Brown ◽  
Zachary S. Jones ◽  
...  
2019 ◽  
Author(s):  
Sylvia L. Rivera ◽  
Akbar Espaillat ◽  
Arjun K. Aditham ◽  
Peyton Shieh ◽  
Chris Muriel-Mundo ◽  
...  

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 bacterial species makes it challenging to determine cross-link function precisely. Here we present a technique to covalently link peptide strands by chemical rather than enzymatic reaction. We employ bio-compatible click chemistry to induce triazole formation between azido- and alkynyl-D-alanine residues that are metabolically installed in the cell walls of Gram-positive and Gram-negative bacteria. Synthetic triazole cross-links can be visualized by substituting azido-D-alanine with azidocoumarin-D-alanine, an amino acid derivative that undergoes fluorescent enhancement upon reaction with terminal alkynes. Cell wall stapling protects the model bacterium Escherichia coli from β-lactam treatment. Chemical control of cell wall structure in live bacteria can provide functional insights that are orthogonal to those obtained by genetics.<br>


2018 ◽  
Author(s):  
Christian R. Zwick ◽  
Hans Renata

We report an efficient ten-step synthesis of antiviral natural product cavinafungin B in 37% overall yield. By leveraging a one-pot chemoenzymatic synthesis of (2S,4R)-4-methylproline and oxazolidine-tethered (Rink-Boc-ATG-resin) SPPS methodology, the assembly of our molecular target could be conducted in an efficient manner.This general strategy could prove amenable to the construction of other natural and unnatural linear lipopeptides. The value of incorporating biocatalytic steps in complex molecule synthesis is highlighted by this work.


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