Spin-Based Quantum Information Processing in Cytoskeletal Filaments Using Nucleoside Phosphates

Abstract Phosphorus nuclear spins are candidates for quantum information processing in biological matter because 31P is a spin-1/2nucleus without an electric quadrupole moment, although coherence remains environment-dependent. Recent work rangesfrom theoretical proposals based on phosphate ions and Posner molecules to experimental demonstrations of room-temperaturequantum logic in adenosine diphosphate. Scaling such approaches in liquid-state molecular systems is difficult becauseslower rotational dynamics in larger phosphate-containing structures weaken motional averaging, restore anisotropic couplings,broaden spectra, and can reduce transverse coherence. We therefore propose investigating a transition to oriented, immobilizedbiomolecular architectures. Filamentous actin and microtubules provide ordered lattices containing bound ADP and GDP/GTP,respectively, at periodic nucleotide-binding sites and offer geometries suitable for orientation-dependent NMR studies. Usingstructural models based on PDB entries 7BT7 and 5SYF, we estimate static intranucleotide 31P–31P dipolar contributionsand corresponding conditional two-spin interaction intervals in aligned lattices. The resulting sub-millisecond interactiontimescales motivate direct measurements of relaxation, linewidths, orientation dependence, and selective control. Cytoskeletalnucleotide-spin lattices therefore merit investigation as candidate platforms for solid-state nuclear magnetic resonance quantuminformation processing in biological matter.