biostudies-literatureToyama YCIHRe2210492119https://www.ebi.ac.uk/biostudies/studies/S-EPMC9457416biostudies-literatureUnknown119(36)Electrostatic interactions and charge balance are important for the formation of biomolecular condensates involving proteins and nucleic acids. However, a detailed, atomistic picture of the charge distribution around proteins during the phase-separation process is lacking. Here, we use solution NMR spectroscopy to measure residue-specific near-surface electrostatic potentials (<i>ϕ</i>_ENS) of the positively charged carboxyl-terminal intrinsically disordered 103 residues of CAPRIN1, an RNA-binding protein localized to membraneless organelles playing an important role in messenger RNA (mRNA) storage and translation. Measured <i>ϕ</i>_ENS values have been mapped along the adenosine triphosphate (ATP)-induced phase-separation trajectory. In the absence of ATP, <i>ϕ</i><subProceedings of the National Academy of Sciences of the United States of AmericaMapping the per-residue surface electrostatic potential of CAPRIN1 along its phase-separation trajectory.PMC9457416FND-148375FND-503573Toyama YForman-Kay JDRangadurai AKKay LEfalseMapping the per-residue surface electrostatic potential of CAPRIN1 along its phase-separation trajectory.Electrostatic interactions and charge balance are important for the formation of biomolecular condensates involving proteins and nucleic acids. However, a detailed, atomistic picture of the charge distribution around proteins during the phase-separation process is lacking. Here, we use solution NMR spectroscopy to measure residue-specific near-surface electrostatic potentials (<i>ϕ</i>_ENS) of the positively charged carboxyl-terminal intrinsically disordered 103 residues of CAPRIN1, an RNA-binding protein localized to membraneless organelles playing an important role in messenger RNA (mRNA) storage and translation. Measured <i>ϕ</i>_ENS values have been mapped along the adenosine triphosphate (ATP)-induced phase-separation trajectory. In the absence of ATP, <i>ϕ</i><sub2022-01-01T00:00:00Z2022 Sep2026-05-27T21:06:27.035Z2025-04-25T16:55:51.218ZS-EPMC94574163604086910.1073/pnas.2210492119