Gadolinium-Based NMR Spin Relaxation Measurements of Near-Surface Electrostatic Potentials of Biomolecules.

NMR spectroscopy is an important tool for the measurement of the electrostatic properties of biomolecules. To this point, paramagnetic relaxation enhancements (PREs) of H nuclei arising from nitroxide cosolutes in biomolecular solutions have been used to measure effective near-surface electrostatic potentials (ϕ) of proteins and nucleic acids. Here, we present a gadolinium (Gd)-based NMR method, exploiting Gd chelates with different net charges, for measuring ϕ values and demonstrate its utility through applications to a number of biomolecular systems.

Phosphorylation by Protein Kinase C Weakens DNA-Binding Affinity and Folding Stability of the HMGB1 Protein.

The HMGB1 protein typically serves as a DNA chaperone that assists DNA-repair enzymes and transcription factors but can translocate from the nucleus to the cytoplasm or even to extracellular space upon some cellular stimuli. One of the factors that triggers the translocation of HMGB1 is its phosphorylation near a nuclear localization sequence by protein kinase C (PKC), although the exact modification sites on HMGB1 remain ambiguous. In this study, using spectroscopic methods, we investigated the HMGB1 phosphorylation and its impact on the molecular properties of the HMGB1 protein.

Influence of an Intrinsically Disordered Region on Protein Domains Revealed by NMR-Based Electrostatic Potential Measurements.

Many human proteins possess intrinsically disordered regions containing consecutive aspartate or glutamate residues ("D/E repeats"). Approximately half of them are DNA/RNA-binding proteins. In this study, using nuclear magnetic resonance (NMR) spectroscopy, we investigated the electrostatic properties of D/E repeats and their influence on folded domains within the same protein.