Publications

DEER of Singly Labelled Proteins to Evaluate Supramolecular Packing of Amyloid Fibrils

The formation of protein amyloid fibrils in the brain is a hallmark of various neurodegenerative diseases, including Alzheimer diseases and Parkinson diseases. Amyloid fibrils are highly ordered aggregates in which proteins folded in two-dimensional layers stack along one axis to form elongated linear assemblies. The specific conformations adopted by the proteins within each layer of the amyloid correlates with the pathology. Furthermore, their spreading and templating competency relies on strict in register packing of the folded proteins along the fibril growing axis. There is a need for tools to characterize not only the protein fold across the fibril cross section but also the spatial ordering of the proteins stacked along the amyloid fibril axis. We present an approach based on double electron electron resonance spectroscopy (DEER) using singly labelled tau protein assembled in amyloid fibrils that can deliver an apparent dimensionality of the supramolecular organization of tau fibrils. The parameters of the DEER background function can be used to assess the amyloid core location and packing order, and track time-resolved formation of aggregation intermediates. Showcasing the method on tau, we demonstrate that heparin-induced tau fibrils are mispacked while seeded aggregation can template amyloid fibrils with a higher packing order. This study benchmarks a new method that will provide critical structural insights into amyloid assemblies.

A water-pinning hot spot drives templated tau aggregation

Tau assembles into fibrillar aggregates that are pathological hallmarks of a group of neurodegenerative diseases collectively called tauopathies. Templated aggregation of naïve tau to seeding-competent fibrils that proceed from cell to cell is a key driver of prion-like progression of tauopathies. This study tests the hypothesis that tau, an intrinsically disordered protein, achieves in-register stacking to form seed-competent fibrils by a pinning action of tau to each other and/or the seed surface via a single dominant hotspot to avoid mismatch in tau stacking to fibrils. Structured solvation water has been proposed to be a signature of such hot spots at both the tau fibril-end surface and soluble tau monomers. Although jR2R3-P301L tau exhibits a heterogeneous hydration landscape in its intrinsically disordered state, with enhanced water structuring near the P301L mutation site, it is unclear whether a localized hotspot exists at the fibril end surface and surface water facilitates the initial contacts in templated aggregation. Using rapid ¹H-¹⁵N SOFAST-HMQC NMR to track seed-induced aggregation of jR2R3-P301L in real time, complemented by molecular dynamics simulation of fibril surface hydration, we identify a residue-specific pinning hotspot that is prone to dewetting followed by sequential folding and incorporation of the remaining segment in a two-step dock-and-lock process. Site-specific spin labeling further demonstrates that blocking this pinning hotspot disrupts templated aggregation, leading to shorter fibrils. The identification of a dominant pinning site will facilitate the rational design of binders to effectively disrupt fibril extension or serve as diagnostic or therapeutic strategies.

Charge Dependence of Local Hydration Dynamics in Poly(Acrylic Acid) Solutions

Localized measurements of hydration dynamics surrounding poly(acrylic acid) (pAA) chains are executed using Overhauser dynamic nuclear polarization relaxometry to determine the role of polymer protonation state on the polymer solvation environment. Alterations in polymer concentration and solution pH uncovered three different regimes of local water dynamics ranging from bulk-water-like to subdued water diffusivity. These experiments, combined with molecular dynamics simulations, reveal that the presence of deprotonated carboxylic acid groups promotes a hydrophilic local environment and extended polymer chain configurations that together incentivize the incorporation of bulk-like water near the polymer. This results in a stretched polymer conformation that leads to faster observed hydration dynamics in the local hydration environment. Meanwhile, protonated carboxylic acid groups are expected to engage in intrapolymer hydrogen bonding between monomer groups, resulting in a more collapsed conformation and slower observed hydration dynamics. The importance of the carboxylic acid groups on mediating hydration behavior is further illustrated by their role in dictating the solvation environment around poly(acrylic acid-stat-(poly(ethylene glycol) methyl ether acrylate) (p(AA-stat-PEGMEA)) copolymers with varying monomer ratios. These local hydration measurements establish a connection between local water dynamics and polymer chain conformation and may provide additional molecular perspective into poly(acrylic acid)’s classification as a superabsorbent polymer.

Quantum transduction from electron spin state to signaling in wild-type AsLOV2

Coherent electron-spin dynamics has been shown to modulate flavoprotein fluorescence in vivo, but not the chemistry by which a protein signals. Here we show that a magnetic field modulates formation of the covalent FMN-cysteine photoadduct that constitutes the signaling state of wild-type Avena sativa LOV2 (AsLOV2), via a spin-selective radical-pair reaction. AsLOV2 was thought magnetically inactive, but a fluorescence magnetic field effect (MFE) emerges near 100 mT and reaches 7% by 1300 mT. Tracking the photoadduct by UV-vis absorption, we find that 650 mT raises the signaling state population and shortens the product formation time constant by 6.7 ± 0.6%. The short FMN-cysteine separation produces a large dipolar coupling that blocks hyperfine-driven triplet-singlet interconversion at low field; the unusually large flavin-cysteinyl radical g-factor difference overcomes it at high field. The same proximity enables covalent bond formation of radical pairs in a singlet state. This arrangement is canonical in LOV domains, so magnetically enhanced signaling likely extends across natural and engineered photoreceptors

Reconstructing time-resolved inter-residue distance distributions in a protein ensemble during functional dynamics in solution

Reconstructing time-resolved inter-residue distance distributions during protein functional dynamics in the solution state is known to be a difficult and important problem. This article presents a technique for extracting spin-spin (as a proxy for residue-residue) distance distributions on doubly-spin-labeled proteins from rapid-scan time-resolved Gd-Gd electron paramagnetic resonance (rs-TiGGER) spectra recorded near room temperature in solution at 240 GHz. We use a best-fit technique that convolves a dipolar kernel matrix with an intrinsic, non-dipolar-broadened (single-labeled) spectrum. The kernel incorporates the effect of solution-state tumbling on the dipolar broadening using a correlation function that bridges the static and rapidly tumbling regimes. We apply the technique to AsLOV2, a protein domain with a dark-state crystal structure that is well-known from X-ray crystallography, but a less well-characterized and disordered tertiary structure that manifests after photoactivation at 450 nm. Informed by principal component analysis, we assume that the underlying distance distribution may be approximated by a sum of two Gaussian distributions. The fits returned time-resolved, light-activated populations with mean distances of 2.596_-0.045^+0.049 nm (dark) and 4.04_-0.45^+0.92 nm (lit) in the wild type, and 2.55_-0.11^+0.13 nm (dark) and 4.4_-0.9^+1.6 nm (lit) in an N414Q mutant, with nearly complete unfolding (within fit uncertainty) of the active, light-sensitive fraction. The extracted distance distributions and their accompanying uncertainties are consistent within uncertainty with molecular dynamics simulations of the equilibrated protein structure.

tRNA-derived fragments elevated in Alzheimer’s disease facilitate Tau aggregation

Tauopathies, including Alzheimer’s disease (AD), are driven by pathological Tau aggregation, a process that requires co-factors. Small RNAs (sRNA) have been proposed as such co-factors, yet little is known about endogenous transcripts that promote Tau pathology. We identify stress-induced tRNA-derived RNAs or fragments (tDRs/tRFs) as the most dysregulated sRNA class in human AD brains, PS19 mice overexpressing mutant human Tau, and human neuronal tauopathy models. Notably, the highly accumulating 5’Glu^CTC and 5’Gly^GCC tRFs directly bind Tau and induce its phosphorylation, oligomerization, fibril formation, and impact neurite growth. 5’Glu^CTC is enriched in pathological Tau precipitates and co-localizes with oligomeric Tau in PS19 mouse brains. Inhibiting 5’Glu^CTC mitigates Tau pathology. Furthermore, these tRFs are highly secreted by neurons and can be taken up by recipient cells, contributing to Tau pathology. Our findings establish 5’Glu^CTC as a key regulator of Tau aggregation and suggest its inhibition as a promising therapeutic strategy for tauopathies.

Water-Mediated Phosphoryl Wires Stabilize Pathological Tau Fibrils​

Hyperphosphorylation of tau is a hallmark of tauopathies, with specific phosphorylation sites elevated in pathological fibrils. Yet, the molecular role of this post-translational modification (PTM) in driving tau aggregation remains unclear. Tau proteins assemble in register, placing high-phosphoryl groups ~4.8 Å apart for high abundance PTMs, requiring an energetically favorable arrangement. This study tests the hypothesis that phosphoryl groups within the fibril core-forming segment readily associate into an extended “wire” that stabilizes the amyloid fibril, counter to the common assumption that closely packed phosphoryl groups is energetically unfavorable due to electrostatic repulsion. We examined two phosphorylation sites linked to neurodegeneration, serine 305 (S305^p) and tyrosine 310 (Y310^p), using seeding-competent fibrils of the tau peptide jR2R3-P301L. Multiple-quantum spin counting (MQ-SC) by ³¹P solid-state NMR with dynamic nuclear polarization revealed at least six phosphorus spins arranged in 1D within a protofibril, consistent with the observed MQ coherence order of four. Molecular dynamics simulations and 2D ¹H-³¹P heteronuclear correlation NMR and revealed water-mediated phosphoryl wires enhancing the stability and seeding competency of fibrils made of S305^p-phosphorylated jR2R3-P301L compared to the unmodified one. This work introduces the concept that phosphorylation within tau’s core can promote fibril registry and stability through water-mediated hydrogen-bonded phosphoryl wires.

Detection of Mutation-Induced Conformational Changes in an Intrinsically Disordered Protein by Double Quantum Coherence Electron Spin Resonance Methodology

Exchange coupling-assisted ¹³C dynamic nuclear polarization in microdiamond at 14 T

We investigate nitrogen substitution defects, also known as P1 centers, in Type 1b diamonds generated under high pressure and high temperature (HPHT) as a source of electron spin polarization. The open question was how readily electron spin polarization in this diamond transfers to ¹³C nuclear spins within the diamond matrix at 14 T by dynamic nuclear polarization (DNP). The goal was to refine the model for clustered P1 centers in HPHT diamonds and evaluate their potential as a source for DNP hyperpolarization or contrast. The study relied on frequency-stepped measurements of DNP profiles under magic angle spinning (MAS) using the mm-wave output of a frequency-tunable gyrotron and a regular superconducting NMR magnet at a single field. We observe up to 700-fold ¹³C on/off signal enhancements in both MAS and static mode at room temperature, and 130-fold between 35 and 100 K. Modelling the experimental results revealed the dominant role of P1 clusters harboring inter-P1 dipolar and exchange couplings exceeding 100 MHz in achieving ¹³C DNP at 14.1 T. Our results exemplify the importance of exchange coupling for high-field DNP and provides a refined model for DNP via P1 centers of HPHT diamonds.

Pump-Induced Dipolar Order to Evaluate Electron Spin Coupling Networks and Many-Body Effects

Networks of coupled electron spins are integral to applications in dynamic nuclear polarization, quantum information science, and materials properties emerging from many-body correlations. A minimal condition for electron spin entanglement or many- body spin correlations is dipolar order, yet techniques for creating and characterizing electron dipolar order of paramagnetic species are not broadly available. Here, we generate pump-induced dipolar order between P1 centers in powdered diamond samples and probe its formation by ELDOR (ELectron DOuble Resonance) and OOP-ESEEM (Out-Of-Phase Electron Spin Echo Envelope Modulation). ELDOR experiments on P1 centers show electron spin hyperpolarization which we attribute to the generation of dipolar order and subsequent conversion to Zeeman order. Pump-initialized OOP- ESEEM directly detects P1 dipolar order, with simulations confirming the experimental signatures originate from a heterogeneous network of coupled P1 centers. These results establish new approaches for monitoring dipolar order formation and probing materials’ potential for many-body effects.

Protein-Like Polymer for Inhibition of Tau Fibril Propagation in Human-Derived Models of Neurodegeneration

The misfolding, aggregation, and spread of tau protein fibrils underlie tauopathies, a diverse class of neurodegenerative diseases for which effective treatments remain elusive. Among these are corticobasal dementia (CBD) and progressive supranuclear palsy (PSP), canonical examples of 4-repeat (4R) tauopathies characterized by tau isoforms exclusively with four microtubule-binding repeat domains. We target this 4R tau isoform-specific mechanism by focusing on misfolded tau’s distinctive stem-loop-stem structural motif formed by the junction of the 4R-defining alternatively spliced exon and the adjacent constitutive exon. A synthetic peptide based on this stem-loop-stem sequence can induce aggregation and spread in an isoform-specific manner. Here, we develop a protein-like polymer (PLP) in which multiple copies of this synthetic peptide form a brush-like structure capable of preventing tau aggregation by binding and capping fibril ends in vitro, in human brain organoids, and in cellular models with an EC50 of 105 ± 14 nM. PLPs demonstrate robust activity against fibrils derived from CBD and PSP patient brains and a PS19 mouse tauopathy model. Previous tau-targeted treatments have primarily focused on broad tau clearance, aggregation inhibition, or microtubule stabilization, often lacking isoform specificity and precision. In contrast, this approach targets the 4R tau isoform’s unique structural motif, offering a tailored therapeutic intervention for diseases like CBD and PSP. Supported by prior studies showing blood-brain barrier penetrance and safety profiles, this tau-binding PLP offers a promising translational path toward clinical applications in tauopathy treatment.

Hydration and Polyelectrolyte Properties of Polymeric Zwitterions with Long Carbon Spacers

The antifouling performance of polymeric zwitterions exceeds those of other antifouling coating design strategies and is thought to be related to their strong surface-hydration interactions. However, design rules that connect zwitterion molecular structure with measures of surface hydration and fouling have been slow to emerge. This work probes the effect of the spacer length between the anion and cation on the hydration and ion sorption characteristics of model, carboxybetaine-containing hydrogel materials. In these hydrogels, the relationship between water sorption (swelling) and network mechanics allows for direct insight into intermolecular interactions and hydration structure from a combination of macroscopic and molecular-scale measurements. Control over the hydrogel mesh size tunes the relative strength of interchain interactions, deconvoluting the opposing effects of zwitterion hydrophilicity and associative pairing interactions. Swelling measurements indicate that zwitterions with shorter spacers are less hydrophilic and engage in fewer interchain zwitterion pairing interactions than those with longer spacers. Zwitterions with increasing spacer lengths give rise to distinct deswelling and salt partitioning behaviors with the addition of salt, indicative of appreciable surface charge segregation that may create attractive interactions with foulants. Measurements by Overhauser dynamic nuclear polarization indicated little difference in local water dynamics near zwitterionic polymer surfaces. While the shorter zwitterions studied here are less hydrophilic, they are known to possess superior fouling resistance. This trend is perhaps a result of appreciable surface charges among zwitterions with long spacers rather than hydration interactions alone. The higher degree of fouling observed in zwitterions with long spacers may indicate the role of surface charges in these chemistries.

Solution-Like Water Transport Across Molecular to Macroscopic Length Scales in Crosslinked Poly(Ethylene Glycol Diacrylate) Networks With Tailored Sidechains

Poly(ethylene glycol) (PEG)-based materials, like PEG-diacrylate (PEGDA), are prized for their hydrophilic, inert properties, and leveraged in hydrogels and as membrane mimics. While network chemistry is often tuned for selective transport and antifouling, fundamental understanding of water dynamics at the network surface and the impact on bulk transport is limited. We utilize Overhauser dynamic nuclear polarization (ODNP) to measure nanoscale water diffusivity near a tethered spin label at the water-polymer surface and compare it to bulk water diffusivity from pulsed field gradient (PFG) NMR. Via active ester chemistry, spin labels and varied sidechain chemistries are introduced, modulating network hydrophilicity. Tuning network hydration through crosslinker content and functional groups further impacts water diffusivity. Results show rapid nanoscale water transport at the polymer surface, reflecting network volumetric water content, with further modulation by sidechain functionality. These findings demonstrate PEGDA’s utility as a membrane mimic and the critical impact of network chemistry on water transport.

Coherent Control over Nuclear Hyperpolarization Using an Optically Initializable Chromophore-Radical System

Chromophore radicals (CR) are emerging as important components for molecular quantum information science (QIS), especially in the context of quantum sensing. Here, we demonstrate that the optically hyperpolarized electrons in a 1,6,7,12-tetrakis(4-tert-butylphenoxy)-perylene-3,4,9,10-bis(dicarboximide) (tpPDI) covalently linked to a partially deuterated 1,3-bis(diphenylene)-d16-2-phenylallyl radical (BDPA-d16) can be coherently manipulated via pulsed dynamic nuclear polarization (DNP) methods to transfer polarization to nuclear spins and back. Under light illumination at 85 K, electron hyperpolarization in BDPA is enhanced 2.1- to 2.4-fold over thermal polarization and lasts for more than 100 ms. By applying nuclear orientation via electron spin-locking (NOVEL) DNP, this optically amplified electron hyperpolarization was successfully transferred to a 1H nuclear spin within the CR system and efficiently returned to the electron spin for readout via reverse-NOVEL. The NOVEL transfer efficiency of 65% amounts to a 688-fold nuclear spin hyperpolarization of the target nuclear spin, considering the 2.1-fold electron spin hyperpolarization. This reversible coherent manipulation of hyperpolarization transfer highlights the utility of CR systems to initialize and read out nuclear spin states in a disordered matrix at moderate cryogenic temperatures. Coupled with CRs’ environmental compatibility, tunability, and precise state initialization, these results highlight the promising role of nuclear spins in CRs for QIS applications, including quantum sensing and memory.

Structure-specific Mini-Prion Model for Alzheimer’s Disease Tau Fibrils

A critical discovery of the past decade is that tau protein fibrils adopt disease-specific hallmark structures in each tauopathy. The faithful generation of synthetic fibrils adopting hallmark structures that can serve as targets for developing diagnostic and/or therapeutic strategies remains a grand challenge. We report on a rational design of synthetic fibrils built of a short peptide that adopts a critical structural motif in tauopathy fibrils found in Alzheimer’s Disease (AD) and Chronic Traumatic Encephalopathy (CTE). They serve as minimal prions with exquisite seeding competency, in vitro and in tau biosensor cells, for recruiting tau constructs ten times larger its size en route to AD or CTE fibril structures. We demonstrate that the generation of AD and CTE-like fibril structures is dramatically catalyzed in the presence of mini-AD prions and further influenced by salt composition in solution. Double Electron-Electron Resonance studies confirmed the preservation of AD-like folds across multi-generational seeding. Fibrils formed with the full AD/CTE-like core show strong seeding competency, with their templating effect dominating over the choice of salt composition that tunes the initial selection of AD- and CTE-like fibril populations. The mini-AD prions serve as a potent catalyst with templating capabilities that offer a novel strategy to design pathological tau fibril models.

Hydraulic Activation of the AsLOV2 photoreceptor

How proteins transduce environmental signals into mechanical motion remains a central question in biology. This study tests the hypothesis that blue light activation of AsLOV2 gives rise to concerted water movement that induce protein conformational extensions. Using electron and nuclear magnetic resonance spectroscopy, along with atomistic molecular dynamics simulations at high pressure, we find that activation, whether initiated by blue light or high pressure, is accompanied by selective expulsion of low-entropy, tetrahedrally coordinated “wrap” water from hydrophobic regions of the protein. These findings suggest that interfacial water serves as functional constituents to help reshape the protein’s free energy landscape during activation. Our study highlights hydration water as an active medium with the capacity to drive long-range conformational changes underlying protein mechanics and offers a new conceptual understanding for engineering externally controllable protein actuators for biomedical studies to smart materials.

Water-directed pinning is key to tau prion formation

Tau forms fibrillar aggregates that are pathological hallmarks of a family of neurodegenerative diseases known as tauopathies. The synthetic replication of disease-specific fibril structures is a critical gap for developing diagnostic and therapeutic tools. This study debuts a strategy of identifying a critical and minimal folding motif in fibrils characteristic of tauopathies and generating seeding-competent fibrils from the isolated tau peptides. The 19-residue jR2R3 peptide (295 to 313) which spans the R2/R3 splice junction of tau, and includes the P301L mutation, is one such peptide that forms prion-competent fibrils. This tau fragment contains the hydrophobic VQIVYK hexapeptide that is part of the core of all known pathological tau fibril structures and an intramolecular counterstrand that stabilizes the strand–loop–strand (SLS) motif observed in 4R tauopathy fibrils. This study shows that P301L exhibits a duality of effects: it lowers the barrier for the peptide to adopt aggregation-prone conformations and enhances the local structuring of water around the mutation site to facilitate site-directed pinning and dewetting around sites 300-301 to achieve in-register stacking of tau to cross β-sheets. We solved a 3 Å cryo-EM structure of jR2R3-P301L fibrils in which each protofilament layer contains two jR2R3-P301L copies, of which one adopts a SLS fold found in 4R tauopathies and the other wraps around the SLS fold to stabilize it, reminiscent of the three- and fourfold structures observed in 4R tauopathies. These jR2R3-P301L fibrils are competent to template full-length 4R tau in a prion-like manner.

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

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

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.

Localized Reconstruction of Multimodal Distance Distribution from DEER Data of Biopolymers

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.