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Structure and ligand specificity of Borrelia burgdorferi BmpA

BmpA is a putative substrate-binding protein from Borrelia burgdorferi, the causative agent of Lyme disease, an organism with limited metabolic capacity that relies on salvage pathways rather than de novo nucleotide biosynthesis. Here, we determine the crystal structure of BmpA to a resolution of 2.6 [A], revealing a conserved substrate-binding protein fold with a deeply buried nucleoside-binding pocket. Using microscale thermophoresis, we show that BmpA binds thymidine with high affinity fol...

— Liu, Q., Nunez, V. A., Fernandez, D., Sharaf, N. G. 2026-01-31 00:00:00

Structure, biosynthesis, and bioactivity of nostolysamides

A recent genome mining study identified class II lanthipeptides encoded in Nostoc punctiforme PCC73102 that contain acyl groups conjugated to Lys side chains. The structure and bioactivity of these peptides, named nostolysamides, were not determined. In this study, we heterologously produced the nostolysamides by co-expression of the NpuA precursor peptide with an N-terminal SUMO tag with the class II lanthipeptide synthetase NpuM in Escherichia coli. We structurally characterized the NpuA-de...

— Weir, E., Anterola, I., van der Donk, W. A. 2026-01-31 00:00:00

Small molecule agonists of 8-oxoguanine DNA glycosylase, OGG1

Base excision repair (BER) is the primary pathway that removes oxidatively-induced DNA base damage from the nuclear and mitochondrial genomes, with 8-oxoguanine DNA glycosylase (OGG1) initiating repair at the two most frequently-formed base lesions: 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxoGua) and 2,6-diamino-4-oxo-5-formamidopyrimidine (FapyGua). Humans expressing a catalytically-compromised variant of OGG1 (S326C) are at increased risk for type 2 diabetes, Alzheimers disease, and Parkinso...

— Luzadder, M. M., Minko, I. G., Moellmer-Gomez, S. A., Tozaki, N. N., Jaruga, P., Dizdaroglu, M., Jin, H., Devereaux, J., Nilsen, A., Lloyd, R. S., McCullough, A. K. 2026-01-31 00:00:00

Engineering the Self-assembly of Bacterial Microcompartment Shell Proteins via Charged Mutations

Protein self-assembly is a fundamental biological process of great importance for the design and synthesis of biomaterials. Developing the ability to precisely manipulate protein assembly would greatly expand both our understanding of the process and our biotechnological capabilities. Within bacteria, proteins that self-organize to form bacterial microcompartments (MCPs) offer an excellent model system for studying protein self-assembly and advancing biomaterial design capabilities. MCPs cons...

— Gomez, A., Mehrafrooz, B., Waltmann, C., Mills, C., Kennedy, N., Miller, J., Tullman-Ercek, D., Olvera de la Cruz, M. 2026-01-30 00:00:00

Principles of in situ protein sequencing: expansion microscopy-adapted Edman degradation and amino acid recognition

The ability to map protein identity, with resolution sufficient to infer interactions, would support analysis of how proteins work together, or malfunction, in biological processes and diseases. Although several emerging technologies aim towards single-molecule protein sequencing, they require proteins to be removed from the nanoscale spatial context of cells and tissues. Expansion microscopy (ExM) has facilitated a diversity of chemical analyses by isotropically separating molecules througho...

— Mitchell, C. M., Tavana, S. Z., Peng, J., Wang, H., Shi, J., Zhang, C., Evgeniou, L., Domecillo, M., Wang, S., Estandian, D. M., Choueiri, A. G., Wong, E., Dohadwala, S., Polizzi, N., Kiessling, L. L., Boyden, E. S. 2026-01-30 00:00:00

DDX3X syndrome mutations lock DDX3X-RNA conformational states to drive persistent pathological condensation and neuronal death

DDX3X is a highly conserved RNA helicase associated with RNA metabolism, translation initiation, and deciding cell fate choices. Spontaneous mutations in DDX3X cause a rare genetic human disorder called DDX3X syndrome, showing a spectrum of neurodevelopmental and intellectual abnormalities. How missense mutations in DDX3X lead to aberrant cellular functions and pathological consequences is unclear. Here, we demonstrate that specific DDX3X syndrome missense mutations induce the formation of pe...

— Ghosh, P., Kapuganti, S. K., Gopal, S., Lamba, S., Rajyaguru, P. I., Kesavardhana, S. 2026-01-30 00:00:00

Identification and Evaluation of dibasic piperidines as novel cell wall inhibitors against Mycobacterium tuberculosis

Globally, Mycobacterium tuberculosis remains a significant disease burden. Although effective treatment regimens exist, drug resistance continues to emerge. This clinical resistance, combined with side effects and protracted treatment times from the current front-line therapies, means there is a need to identify novel agents to combat this disease. Here we report on a new chemical series, identified by whole-cell phenotypic growth inhibition screening that demonstrates significant activity ac...

— Naylor, C., Prosser, G. A., Bayliss, T., Berle, L., Wallach, J. B., Kim, H., Olvera, R. A., Thompson, S., Ioerger, T. R., Simpson, L., Casanueva, R., Guijarro-Lopez, L., Read, K. D., Wyatt, P. G., Schnappinger, D., Barry, C. E., Green, S. R., Boshoff, H. I., Cleghorn, L. A. T. 2026-01-30 00:00:00

Structural basis of underwound DNA topology bearing PAM-mutant recognition by AtCas9

The CRISPR-Cas9 system locates genomic targets through gRNA pairing and recognition a protospacer-adjacent motif (PAM). While PAM specificity is typically sequence-determined, we previously found that DNA topology can regulate PAM specificity, relaxing PAMs of various Cas9 effectors and allowing near-PAMless cleavage activity of a type II-C Alicyclobacillus tengchongensis Cas9 (AtCas9). However, the structural mechanism underlying this regulation remains unknown. Here, we report cryo-EM struc...

— Duan, M., Meng, B., Zhou, L., Wu, L., Tong, X., Huang, D., Yin, H., Liu, Z. J., ZHANG, Y. 2026-01-30 00:00:00

Phylogenetic Investigation of the 100 kDa Hexokinase Enzyme Family with the Topiary Ancestral Sequence Reconstruction Pipeline

The 100 kDa hexokinase (HK) enzyme family represents an attractive model to investigate the molecular origins of allosteric regulation in multidomain enzymes. Extant HK homologs are subject to various allosteric phenomena, including activation and inhibition by both homotropic and heterotropic ligands. Here, we report the results of a phylogenetic investigation of this enzyme family using the recently developed Topiary ancestral sequence reconstruction pipeline. The results agree with prior s...

— Freye, C., Whittington, A. C., Miller, B. G. 2026-01-30 00:00:00

Integrative modelling reveals the structure of the human Mic60-Mic19 subcomplex and its role as a diffusion barrier in mitochondria

Mitochondrial crista junctions (CJs) operate as regulated gateways into the cristae microenvironment, whose protein, metabolite, and ion compositions are finely tuned for mitochondrial function. The Mic60-Mic19 complex of the mitochondrial contact site and cristae organizing system (MICOS) complex was suggested to span across CJs and act as a diffusion barrier, but little is known of how its dynamic architecture facilitates this task. To address this open question, we determined the crystal s...

— Nathanail, E., Rolando, E., Ruwolt, M., Zaporozhets, I., Liu, F., Clementi, C., Daumke, O. 2026-01-30 00:00:00

Dietary cholesterol reduces blood pressure and alters lipid profiles in stroke-prone spontaneously hypertensive rats

Cholesterol is widely recognized as a risk factor for cardiovascular disease, yet dietary cholesterol intake has been reported to extend the lifespan of stroke-prone spontaneously hypertensive rats (SHRSP). The mechanisms underlying this paradoxical effect remain unclear. This study investigated changes in organ lipid profiles and associated molecular factors in cholesterol-fed SHRSP rats. Four-week-old male SHRSP/Izm rats were divided into three groups and fed ad libitum for 12 weeks with a ...

— Tatematsu, K., Nishikata, Y., Saito, Y., Matsunaga, T., Ohara, N. 2026-01-30 00:00:00

Evolutionary origin of terpenoid biosynthesis in termites

Termites produce the most diverse array of terpenoids among metazoans, comprising over 200 structures. However, their biosynthesis has not yet been elucidated. Here, we identify a gene family which arose through the duplication of geranylgeranyl pyrophosphate synthase in the common ancestor of Neoisoptera, the terpene-producing termite lineage. We functionally characterized several proteins from this family as terpene synthases generating biologically relevant sesqui- and diterpenes. These in...

— Horacek, N., Luksan, O., Rebholz, Z., Harant, K., Pohl, R., Mutabdzija-Nedelcheva, L., Hellemans, S., Jungwirth, D., Krivanek, J., Amirianova, A., Kyjakova, P., Bourguignon, T., Tholl, D., Hanus, R., Stafkova, J. 2026-01-29 00:00:00

Ex vivo maturation of the malaria parasite egress protease SERA6 aids pathway dissection and inhibitor development.

Release (egress) of malaria parasites from host red blood cells (RBC) is a protease-dependent process involving breakdown of the RBC cytoskeleton by a parasite cysteine protease-like protein called SERA6. In the penultimate step of the egress cascade, SERA6 undergoes autoproteolytic maturation triggered upon cleavage by a serine protease called SUB1 and requiring interactions between SERA6 and fragments of another parasite protein called MSA180. Egress can be blocked by treatment of intraeryt...

— Withers-Martinez, C., Taha, Z., Collins, C. R., Hackett, F., Tan, M. S., Soudy, C., Joshi, D., Redmond, J., Davies, B., Maslen, S., Skehel, M., George, R., Kjaer, S., Blackman, M. J. 2026-01-29 00:00:00

Harnessing FBXO31 with terminal amide-functionalized molecules for targeted protein degradation

Targeted protein degradation (TPD) is a powerful strategy for controlling protein abundance. Here, we establish FBXO31 as a TPD-competent E3 ligase by exploiting its recognition of C-terminal amide-bearing degrons. Using an amidated Ala-Phe motif as a chemical recruiter, multiple small-molecule binders can be transformed into FBXO31-dependent degraders that induce rapid and potent target degradation. Mechanistic studies confirm FBXO31-mediated ternary complex formation and identify key residu...

— Zhang, C., Jin, X., Zhou, C., Martin, J. M., Riha, I. A., Zhang, X. 2026-01-29 00:00:00

Function within Disorder: Small heat shock proteins use different functional regions to chaperone tau aggregation

In numerous neurodegenerative diseases known collectively as tauopathies, the microtubule-associated protein tau forms fibrillar aggregates that are hallmarks of disease pathology. Tauopathies represent a substantial fraction of diseases associated with protein misfolding. Cellular chaperones known as small heat shock proteins (sHSPs) play a critical role in maintaining protein homeostasis by delaying the onset of protein aggregation. Two sHSPs, HSPB1 (Hsp27) and HSPB5 aB-crystallin), are con...

— Cervantes, M., Janowska, M. K., Tuttle, L. M., Nath, A., Klevit, R. E. 2026-01-29 00:00:00

Calcium directs actin assembly via allosteric activation of formin INF2

Calcium signals spatiotemporally orchestrate cytoskeletal dynamics, typically through Rho GTPase-mediated signaling cascades, yet the direct molecular transducers that convert local calcium transients into spatially controlled actin assembly have remained elusive. Here, we uncover a structure-based mechanism by which calcium-bound calmodulin (Ca2+-CaM) directly activates formin INF2 to drive actin assembly. We demonstrate that Ca2+-CaM binds to the diaphanous inhibitory domain (DID) of INF2 w...

— Zhang, B., Zhang, M., Liu, K., Zhao, C., Zhang, J., Liu, Z., Fan, Y., Gu, R.-x., Lin, L., Fu, C., Zhu, J. 2026-01-29 00:00:00

A small molecule PTER-selective inhibitor reduces food intake and body weight

PTER (phosphotriesterase-related) is an amidohydrolase that mediates catabolism of the anorexigenic taurine metabolite N-acetyltaurine. However, the structural basis of PTER ligand binding and catalysis remain unknown, limiting our ability to harness this pathway therapeutically. Here we solve crystal structures of a eukaryotic PTER in apo and product-bound forms. These structures uncover an unexpected pocket homology between PTER and histone deacetylase (HDAC) enzymes. We exploit this simila...

— Fu, S., Wang, L., Li, V. L., Lyu, X., Wei, W., Shi, X., Deng, S., Barber, J., Tahir, U., Adams, C., Carson, A., Hidalgo, B. A., Raffield, L. M., Wilson, J. G., Razumkov, H., Xiao, S., Spaas, J., Fernandez, D., Zhang, T., Gerszten, R. E., Benson, M., Gray, N., Hinshaw, S. M., Long, J. Z. 2026-01-28 00:00:00

MDA5 multimerization on LINE RNA drives pathogenic extracellular immune complexes in autoimmunity

Autoantibodies are hallmarks of many autoimmune diseases, but their potential pathogenic roles, particularly for those targeting intracellular proteins, remain unclear. Anti-MDA5-positive dermatomyositis (anti-MDA5 DM) is characterized by autoantibodies against the intracellular protein MDA51,2, a conserved innate immune receptor that recognizes viral dsRNA by forming filaments3. Here, using four patient-derived monoclonal autoantibodies (mAbs), we reconstitute and define the molecular archit...

— Hsu, T. Y.-T., Wang, X., Isayama, Y., Jung, V., Zhang, J., van Gompel, E., Maadadi, H., Torres, C., Shimazaki-Takahashi, A., Kurihara, N., Kondo, M., Galesic, M., Notarnicola, A., Sultana, S., Maeda, A., Vleugels, R. A., Dellaripa, P. F., Yamashita, T., Ito, Y., Awaji, K., Kotani, H., Matsuda, K. M., Horuluogu, B., Grönwall, C., Joshua, V., Ukai, Y., Hosomi, N., Wagner, D. D., Lundberg, I. E., Kato, K., Hur, S. 2026-01-28 00:00:00

The Shape of Control: How Going in Circles Keeps RNA Catalytically Switched On

RNase P was one of the first enzymes discovered to have an RNA-based catalytic component. Since its identification, it has been extensively studied, particularly in E. coli, due to the ability of its M1 RNA to exhibit in vitro catalytic activity even in the absence of associated protein. In this study, we report G-quadruplex formation as a potential regulatory mechanism that modulates the catalytic activity of this RNA. We observed a significantly higher propensity for G-quadruplex formation ...

— Billings, M. J., Chawla, A. K., Mulla-Feroze, A., Kietrys, A. M. v. 2026-01-28 00:00:00

Re-Engineering P(V) Chemical Warfare: Harnessing Stereogenic Phosphorus-Azoles for Protein Ligand Discovery In Vivo

P(V) electrophiles such as tabun, sarin, soman, and VX are notorious for their lethality and nefarious intent in chemical warfare. Consequently, these deadly agents have largely been abandoned except for fluorophosphonate tool compounds that were repurposed for activity-based protein profiling (ABPP). Stereogenic P(V) centers hold strong potential as enabling scaffolds for synthetic and medicinal chemistry due to their inherent chirality and favorable bioavailability but are limited principal...

— Grams, R. J., Murtagh, O., Ware, M., Vasylevskyi, S., Hsu, K.-L. 2026-01-28 00:00:00

Coupling high-throughput protease enzymology with viral replication reveals biochemical constraints of viral fitness

Proteases govern essential biological processes and are key drug targets, yet how protease sequence variation quantitatively reshapes biochemical parameters and constrains biological fitness remains poorly understood. Here, we integrate high-throughput in vitro enzymology with cellular assays to link protease sequence, biochemistry, and fitness. We extend a microfluidic platform for high-throughput protease enzymology (HT-MEKpro), which is broadly applicable across protease families and catal...

— Aidlen, D., Vo, W. V. T., Young, N. J., Rosecrans, J., Kurianowicz, A., Chuo, S.-W., Asper, G. P. R., Anderson, D., Posner, J. A., Muir, D. F., Freitas, N., Ott, M., Craik, C. S., Taha, T. Y., Pinney, M. M. 2026-01-28 00:00:00

Chemoproteomics discovery of a CNS-penetrant covalent inhibitor of PIKfyve

PIKfyve is a lipid kinase involved in regulating protein clearance mechanisms and is a promising target for the treatment of neurodegenerative diseases. Here, we present the discovery and optimization of a CNS-penetrant covalent PIKfyve inhibitor, DUN058, which achieves sustained target occupancy in vivo. Covalent screening hits, identified from chemoproteomics experiments performed in live cells, were rapidly optimized to deliver a brain-penetrant covalent inhibitor of PIKfyve. This covalenc...

— Burton, A. J., Chupak, L. S., Davis, A. J., Mady, A. S., Meniconi, M., Teobald, B., Dorsey, B. W., Byrne, L. R., Mulhern, R., Lundeen, B., Sorensen, E. W., Patel, B., Brennan, S., Kormocha, D., Tommasi, R., Simpson, G. L., Keillor, J. W., D'Agostino, L., Huang, P. S., Penebre, E. 2026-01-28 00:00:00

MacroH2A-Mediated Gene Repression through Nucleosome Compaction and Remodeling Inhibition

MacroH2A (mH2A) is a histone variant primarily implicated in heterochromatin maintenance and transcriptional repression, yet how its conserved histone-fold and its variant-specific domains reshape chromatin to enforce gene silencing remains poorly understood. Here, we dissect the domain-specific contributions of mH2A to nucleosome dynamics and chromatin remodeling. We show that, in addition to its linker region, the C-terminal tail of mH2A histone-fold also stabilizes nucleosome entry/exit DN...

— Tan, D., Sokolova, V., Jiang, R., Mullins, A., Lee, G., Pan, B. H. 2026-01-28 00:00:00

Structural and functional basis of proton-independent transition metal import by a canonical bacterial Nramp transporter

Natural resistance-associated macrophage proteins (Nramps) are divalent transition metal transporters found in most organisms, typically coupling metal uptake to proton co-transport. How this coupling evolved, however, remains unclear. We present structural, functional, and evolutionary analyses of a clade B Nramp from the gut bacterium Bacteroides fragilis (BfraNramp). Phylogenetic reconstruction positions clade B as the most basal group of canonical Nramps, retaining conserved metal-binding...

— Ray, S., Berry, S. P., Gaudet, R. 2026-01-27 00:00:00

Mechanism of ATXN8OS CTA/CTG repeat-associated non-AUG translation revealed by approaches ranging from cell-free translation to live-cell imaging.

Microsatellite repeat expansions contribute to the pathogenesis of many neurodegenerative disorders. In spinocerebellar ataxia type 8 (SCA8), abnormal expansion of CTA/CTG repeats in the 3' untranslated region of the ATXN8OS (ATXN8 Opposite Strand) gene has been implicated in disease pathology. Although the occurrence of repeat-associated non-AUG (RAN) translation from the ATXN8 transcript has been reported, whether and how RAN translation occurs from the ATXN8OS transcript has remained unexp...

— Sakamoto, S., Ito, H., Hasumi, M., Morisaki, T., Hirano, M., Nagai, Y., Stasevich, T. J., Taguchi, H. J. 2026-01-27 00:00:00

An enzyme-level benchmark based on environmental bacterial laccases for predicting contaminant fate in water

Bacterial laccases are widespread multicopper oxidases whose roles in the fate of anthropogenic chemicals in aquatic environments remain poorly understood. Here, we integrate metagenomic analysis, a miniaturized high-throughput assay and machine learning to establish an enzyme-level benchmark for predicting biotransformation of wastewater-relevant trace organic contaminants by laccase-mediator systems. Using a laccase from an ammonia-oxidizing bacterium as a model enzyme, we screened 183 comp...

— Yu, Y., Zhang, K., Steiner, V.-M., Poltorak, V., Probst, S. I., Robinson, S. L., Hutter, J., Satoh, H., Fenner, K. 2026-01-27 00:00:00

Discovery of Membrane Channel Modulators via DNA-Encoded Library Screening Using Native-Like Membrane Protein Nanoparticles

Developing novel drugs against membrane proteins is a major challenge in drug discovery due to the difficulty of stabilizing these targets for high-throughput screenings. Pannexin 1 (PANX1) is a membrane channel protein involved in various physiological and pathological processes, making it a promising target for drug discovery. However, efforts to develop PANX1-targeting therapeutics have been hindered by the inherent challenges of stabilizing the protein channel and conducting effective pha...

— Reddavide, F. V., Toft-Bertelsen, T. L., Drulyte, I., Gutgsell, A. R., Nguyen, D., Bonetti, S., Vafia, K., Tournillon, A.-S., Heiden, S., Grosser, G., Iric, K., Diez, V., MacAulay, N., Geschwindner, S., Thompson, T., Frauenfeld, J., Loving, R. 2026-01-27 00:00:00

Translesion DNA synthesis on pyrimidine dimers by Plant organellar DNA polymerases is metal-dependent

Ultraviolet (UV) radiation generates crosslinked DNA lesions--primarily cyclobutane pyrimidine dimers (CPDs) and [6-4] photoproducts ([6-4] PPs)--that block the progression of replicative DNA polymerases. In plants, these lesions are efficiently removed from nuclear DNA by dedicated repair pathways; however, comparable repair mechanisms are absent in plastids and mitochondria. Consequently, how plant organellar DNA polymerases (POPs) tolerate or bypass UV-induced damage has remained unclear. ...

— Baruch-Torres, N., Park, J., Castro-Torres, E., Iwai, S., Yin, Y. W., Brieba, L. G. 2026-01-27 00:00:00

A peptide catalyst can replace an essential enzyme in a eukaryotic cell

Protein enzymes are central to modern biology, yet how catalysis emerged before the evolution of large, folded proteins remains unresolved. Here we show that a short, genetically encoded peptide can replace an essential enzyme in a living eukaryotic cell. We designed minimal peptides containing a Cys-Xaa-Cys catalytic motif and an endoplasmic reticulum retention signal, and identified variants that rescue the otherwise lethal deletion of protein disulfide isomerase (PDI) in Saccharomyces cere...

— Podolsky, K. A., Molina, O. J., Long, V. Y., Raines, R. T. 2026-01-27 00:00:00

Chemical control of 2'-hydroxyl-dependent Cas9 target engagement enables CRISPR RNA ribose replacement

Advanced CRISPR-based therapies benefit from CRISPR RNA (crRNA) with high nuclease resistance and enhanced drug-like properties, which is primarily achieved through chemical replacement of the RNA ribose moiety. However, for gene editing enzymes like CRISPR-Cas9 a handful of residues cannot be replaced with chemical ribose analogues, limiting the scope of therapeutic strategies. The mechanism underlying this restriction has remained unclear. Here, using nucleic acid chemistry, biochemistry, c...

— Pater, A. A., Barber, H. M., Sudhakar, S., Chilamkurthy, R., Jana, S. K., Parasrampuria, M. A., Bosmeny, M. S., Graczyk-Marrs, J. A., Eddington, S. B., Blazier, C. A., Abdullahu, L., Malek-Adamian, E., Barkau, C. L., O'Reilly, D., Korolev, S., Pradeepkumar, P. I., Damha, M. J., Gagnon, K. T. 2026-01-26 00:00:00