Solvent PRE and effective near surface electrostatics: theory, methods, and biological insights

Area of Science:

• Biochemistry
• Biophysics
• Structural Biology

Background:

• Electrostatic interactions are crucial for biomolecular structure, dynamics, and function.
• Experimentally resolving local electrostatic potentials at residue-level is challenging.
• Solvent paramagnetic relaxation enhancement (sPRE) is a nuclear magnetic resonance (NMR) technique for probing near-surface electrostatic environments.

Purpose of the Study:

• To review the theoretical framework and recent advances in sPRE.
• To discuss the effective near-surface electrostatic potential (ENS) derived from sPRE.
• To highlight applications of sPRE and ENS in complex biological systems.

Main Methods:

• Utilizing sPRE to quantify near-surface electrostatic environments.
• Analyzing spectral density, spatial decomposition, and intermolecular potentials.
• Comparing transverse relaxation rates induced by paramagnetic cosolutes of differing charge to determine ENS.

Main Results:

• sPRE directly quantifies local electrostatic fields without prior structural information.
• ENS captures local electrostatic fields by comparing relaxation rates.
• sPRE and ENS reveal electrostatic modulation in proteins, nucleic acids, and disordered systems.

Conclusions:

• sPRE and ENS are powerful tools for mapping biomolecular electrostatics.
• These methods offer insights into phase separation, ion atmospheres, and biomolecular interactions.
• Future developments promise enhanced electrostatics mapping by NMR.