Octahedral Trifluoromagnesate, an Anomalous Metal Fluoride Species, Stabilizes the Transition State in a Biological Motor.

ABSTRACT: Isoelectronic metal fluoride transition state analogue (TSA) complexes, MgF₃ ^- and AlF₄ ^-, have proven to be immensely useful in understanding mechanisms of biological motors utilizing phosphoryl transfer. Here we report a previously unobserved octahedral TSA complex, MgF₃(H₂O)^-, in a 1.5 Å resolution Zika virus NS3 helicase crystal structure. ¹⁹F NMR provided independent validation and also the direct observation of conformational tightening resulting from ssRNA binding in solution. The TSA stabilizes the two conformations of motif V of the helicase that link ATP hydrolysis with mechanical work. DFT analysis further validated the MgF₃(H₂O)^- species, indicating the significance of this TSA for studies of biological motors.

SUBMITTER: Ge M 

PROVIDER: S-EPMC7944477 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature