Conformational dynamics and alignment properties of loop lanthanide-binding-tags (LBTs) studied in interleukin-1β.

Encodable lanthanide binding tags (LBTs) have become an attractive tool in modern structural biology as they can be expressed as fusion proteins of targets of choice. Previously, we have demonstrated the feasibility of inserting encodable LBTs into loop positions of interleukin-1β (Barthelmes et al. in J Am Chem Soc 133:808-819, 2011).

Heteronuclear Cross-Relaxation under Solid-State Dynamic Nuclear Polarization.

We report on the spontaneous polarization transfer from dynamically hyperpolarized H to C during magic-angle spinning dynamic nuclear polarization (DNP) at temperatures around 100 K. The transfer is mediated by H-C cross-relaxation within methyl groups due to reorientation dynamics, and results in an inverted C NMR signal of enhanced amplitude. Further spreading of transferred polarization can then occur via C-C spin-diffusion.

Encoded loop-lanthanide-binding tags for long-range distance measurements in proteins by NMR and EPR spectroscopy.

We recently engineered encodable lanthanide binding tags (LBTs) into proteins and demonstrated their applicability in Nuclear Magnetic Resonance (NMR) spectroscopy, X-ray crystallography and luminescence studies. Here, we engineered two-loop-LBTs into the model protein interleukin-1β (IL1β) and measured (1)H, (15)N-pseudocontact shifts (PCSs) by NMR spectroscopy. We determined the Δχ-tensors associated with each Tm(3+)-loaded loop-LBT and show that the experimental PCSs yield structural information at the interface between the two metal ion centers at atomic resolution.