**Cécile Dubois, Isaline Herrada, Philippe Barthe and Christian Roumestand \***

Centre de Biochimie Structurale, INSERM U1054, CNRS UMR 5048, Université de Montpellier, 34090 Montpellier, France; cecile.dubois@cbs.cnrs.fr (C.D.); isaline.herrada@yahoo.fr (I.H.); Philippe.Barthe@cbs.cnrs.fr (P.B.)

**\*** Correspondence: christian.roumestand@cbs.cnrs.fr; Tel.: +33-4-6741-7704

Academic Editor: Marilisa Leone

Received: 15 October 2020; Accepted: 23 November 2020; Published: 26 November 2020

**Abstract:** High-hydrostatic pressure is an alternative perturbation method that can be used to destabilize globular proteins. Generally perfectly reversible, pressure exerts local effects on regions or domains of a protein containing internal voids, contrary to heat or chemical denaturant that destabilize protein structures uniformly. When combined with NMR spectroscopy, high pressure (HP) allows one to monitor at a residue-level resolution the structural transitions occurring upon unfolding and to determine the kinetic properties of the process. The use of HP-NMR has long been hampered by technical difficulties. Owing to the recent development of commercially available high-pressure sample cells, HP-NMR experiments can now be routinely performed. This review summarizes recent advances of HP-NMR techniques for the characterization at a quasi-atomic resolution of the protein folding energy landscape.

**Keywords:** protein folding; NMR; High Hydrostatic Pressure
