Quantum Resonance Sensing of Molecular Activity in Water

Hydrolytically Stable Phosphonate‐Based Metal–Organic Frameworks for Harvesting Water from Low Humidity Air

H. Xie, A. Atilgan, F. Joodaki, J. Cui, X. Wang, H. Chen, L. Yang, X. Zhang, F. A. Son, K. B. Idrees, A. M. Wright, J. L. Wells, W. Morris, J. Klein, L. Franklin, F. Harrington, S. Herrington, S. Han, K. O. Kirlikovali, T. Islamoglu, R. Q. Snurr, O. K. Farha
https://doi.org/10.1002/smll.202503178

Harvesting water from air offers a promising solution to the global water crisis. However, existing sorbents often struggle in arid climates due to limitations such as low sorption capacities, hydrolytic instability, slow mass transport, high desorption enthalpy, and costly operation. Phosphonate-based metal–organic frameworks (MOFs), known for their exceptional water stability, have not been extensively explored for water harvesting. This study systematically investigates the performance of STA-12 (M═Co, Ni, Mg) and STA-16 (M═Co, Ni), a series of stable phosphonate-based MOFs, as water sorbents. STA-12 MOFs demonstrate remarkable adsorption at ultra-low humidity (<10%), while STA-16(Co) exhibits a high water uptake capacity of 0.54 g g⁻¹ at 10–50% relative humidity (RH) and 0.72 g g⁻¹ at 34% RH. Molecular simulations and solid-state NMR identified liquid-like water, critical for harvesting applications, as the key contributor to the superior sorption performance of STA-16(Co). Scalable aqueous synthesis methods are developed, producing tens of grams of MOFs per batch without high-pressure equipment. A prototype device incorporating STA-12(Ni) demonstrated the feasibility of these materials for real-world water harvesting, showcasing their potential to address water scarcity in arid regions

Passaging Human Tauopathy Patient Samples in Cells Generates Heterogeneous Fibrils with a Subpopulation Adopting Disease Folds

Z, Zeng, K. Tsay, V. Vijayan, M. P. Frost, S. Prakash, A. Quddus, A. Albert, M. Vigers, M. Srivastava, A.L. Woerman, S. Han
bioRxiv

The discovery by cryo-electron microscopy (cryo-EM) that the neu-ropathological hallmarks of different tauopathies, including Alzheimer’s disease, corticobasal degeneration (CBD), and progressive supranuclear palsy (PSP), are caused by unique misfolded conformations of the protein tau is among the most profound developments in neurodegenerative disease research. To capitalize on these discoveries for therapeutic development, one must achieve in vitroreplication of tau fibrils that adopt the representative tauopathy disease folds, which represents a grand challenge for the field. A widely used approach has been seeded propagation using pathological tau fibrils derived from post-mortem patient samples in biosensor cells that expresses a fragment of the tau protein known as K18, or Tau4RD, containing the microtubule-binding repeat domain of tau as the substrate. The new insights from cryo-EM raised the question of whether the Tau4RD fragment is capable of adopting characteristic tau folds found in CBD and PSP patient fibrils, and whether cell-passaged and amplified tau fibrils can be used as seeds to achieve cell-free assembly of recombinant 4R tau into fibrils without the addition of cofactors. Using Double Electron Electron Resonance (DEER) spectroscopy, we discovered that cell-passaged pathological seeds generate heterogeneous fibrils that are, however, distinct between the CBD and PSP lysate-seeded fibrils, and vastly different from heparin-induced tau fibril structures. Moreover, the lysate-seeded fibrils contain a characteristic sub-population that resembles the disease fold corresponding to the respective starting patient sample. These findings indicate that templated propagation using CBD and PSP patient-derived fibrils is possible with a tau fragment that does not contain the entire pathological fibril core, but also that additional mechanisms must be tuned to converge on a homogeneous fibril population.

https://doi.org/10.1101/2023.07.19.549721

Localized Reconstruction of Multimodal Distance Distribution from DEER Data of Biopolymers

K. Tsay, T. Keller, Y. Fichou, J.H. Freed, S. Han, M. Srivastava
bioRxiv

Pulsed Dipolar ESR Spectroscopy (PDS) is a uniquely powerful technique to characterize the structural property of intrinsically disordered proteins (IDPs) and polymers and the conformational evolution of IDPs and polymers, e.g. during assembly, by offering the probability distribution of segment end-to-end distances. However, it is challenging to determine distance distribution P(r) of IDPs by PDS because of the uncertain and broad shape information that is intrinsic to the distance distribution of IDPs. We demonstrate here that the Srivastava-Freed Singular Value Decomposition (SF-SVD) point-wise mathematical inversion method along with wavelet denoising (WavPDS) can aid in obtaining reliable shapes for the distance distribution, P(r), for IDPs. We show that broad regions of P(r) as well as mixed narrow and broad features within the captured distance distribution range can be effectively resolved and differentiated without a priori knowledge. The advantage of SF-SVD and WavPDS is that the methods are transparent, requiring no adjustable parameters, the processing of the magnitude for the probability distribution is performed separately for each distance increment, and the outcome of the analysis is independent of the user’s judgement. We demonstrate the performance and present the application of WavPDS and SF-SVD on model ruler molecules, model polyethylene glycol polymers with end-to-end spin labeling, and IDPs with pairwise labeling spanning different segments of the protein tau to generate the transparent solutions to the P(r)’s including their uncertainties and error analysis.

https://doi.org/10.1101/2025.01.02.631084