Pulse Dipolar EPR Reveals Double-Histidine Motif Cu^II-NTA Spin-Labeling Robustness against Competitor Ions.

ABSTRACT: Pulse-dipolar EPR is an appealing strategy for structural characterization of complex systems in solution that complements other biophysical techniques. Significantly, the emergence of genetically encoded self-assembling spin labels exploiting exogenously introduced double-histidine motifs in conjunction with Cu^II-chelates offers high precision distance determination in systems nonpermissive to thiol-directed spin labeling. However, the noncovalency of this interaction exposes potential vulnerabilities to competition from adventitious divalent metal ions, and pH sensitivity. Herein, a combination of room-temperature isothermal titration calorimetry (ITC) and cryogenic relaxation-induced dipolar modulation enhancement (RIDME) measurements are applied to the model protein Strep

SUBMITTER: Wort JL 

PROVIDER: S-EPMC8006131 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature