The cell wall is essential for the survival of bacteria. It gives the bacterial cell its shape and protects it against osmotic pressure, while allowing cell growth and division.
The machinery involved in the synthesis of this envelop is crucial and is one of the main antibiotic target. Different proteins as transpeptidases, transpeptidase activators or hydrolases are recruited to maintain the morphogenesis of this polymer during the bacterial cell cycle. Based on few examples involved in the machinery of synthesis of the peptidoglycan, we will present a combination of liquid and solid-state NMR that can be a powerful tool to screen for cell-wall interacting proteins in vitro and on cell.
In particular, we have explored the possibilities to study the PG with ultra-fast (100 kHz) magic-angle spinning NMR. We show that highly resolved spectra can be obtained, and we have developed strategies to obtain site-specific resonance assignments and distance information. we have also in parallel investigated the potential of Dynamic Nuclear Polarization (DNP) to investigate cell surface directly in intact cells.
Altogether, NMR approaches developed here propose new routes to fill the gap between in vitro studies of isolated biomacromolecules and in vivo cell biology studies in order to investigate cell surfaces and decipher key biological processes involved.