Results
- Showing results for:
- Reset all filters
Search results
-
Journal articleGao F, Ye F, Buck M, et al., 2025,
Subunit specialization in AAA+ proteins and substrate unfolding during transcription complex remodeling
, Proceedings of the National Academy of Sciences, Vol: 122, ISSN: 0027-8424Bacterial RNA polymerase (RNAP) is a multisubunit enzyme that copies DNA into RNA in a process known as transcription. Bacteria use σ factors to recruit RNAP to promoter regions of genes that need to be transcribed, with 60% bacteria containing at least one specialized σ factor, σ54. σ54 recruits RNAP to promoters of genes associated with stress responses and forms a stable closed complex that does not spontaneously isomerize to the open state where promoter DNA is melted out and competent for transcription. The σ54-mediated open complex formation requires specific AAA+ proteins (ATPases Associated with diverse cellular Activities) known as bacterial enhancer-binding proteins (bEBPs). We have now obtained structures of new intermediate states of bEBP-bound complexes during transcription initiation, which elucidate the mechanism of DNA melting driven by ATPase activity of bEBPs and suggest a mechanistic model that couples the Adenosine triphosphate (ATP) hydrolysis cycle within the bEBP hexamer with σ54 unfolding. Our data reveal that bEBP forms a nonplanar hexamer with the hydrolysis-ready subunit located at the furthest/highest point of the spiral hexamer relative to the RNAP. ATP hydrolysis induces conformational changes in bEBP that drives a vectoral transiting of the regulatory N terminus of σ54 into the bEBP hexamer central pore causing the partial unfolding of σ54, while forming specific bEBP contacts with promoter DNA. Furthermore, our data suggest a mechanism of the bEBP AAA+ protein that is distinct from the hand-over-hand mechanism proposed for many other AAA+ proteins, highlighting the versatile mechanisms utilized by the large protein family.
-
Journal articleIshimoto N, Wong JLC, He S, et al., 2025,
Cryo-EM structure of the conjugation H-pilus reveals the cyclic nature of the TrhA pilin
, Proceedings of the National Academy of Sciences, Vol: 122, ISSN: 0027-8424Conjugation, the major driver of the spread of antimicrobial resistance genes, relies on a conjugation pilus for DNA transfer. Conjugative pili, such as the F-pilus, are dynamic tubular structures, composed of a polymerized pilin, that mediate the initial donor–recipient interactions, a process known as mating pair formation (MPF). IncH are low-copy-number plasmids, traditionally considered broad host range, which are found in bacteria infecting both humans and animals. The reference IncHI1 plasmid R27, isolated from Salmonella enterica serovar Typhi, encodes the conjugative H-pilus subunit TrhA containing 74 residues after cleavage of the signal sequence. Here, we show that the H-pilus forms long filamentous structures that mediate MPF and describe its cryoelectron-microscopic (cryo-EM) structure at 2.2 Å resolution. Like the F pilus, the H-pilin subunits form helical assemblies with phospholipid molecules at a stoichiometric ratio of 1:1. While there were previous reports that the T-pilus from Agrobacterium tumefaciens was composed of cyclic subunits, three recent cryo-EM structures of the T-pilus found no such cyclization. Here, we report that the H-pilin is cyclic, with a covalent bond connecting the peptide backbone between the N and C termini. Both the cryo-EM map and mass spectrometry revealed cleavage of the last five residues of the pilin, followed by cyclization via condensation of the amine and carboxyl residues. Mutagenesis experiments revealed that loss of cyclization abolished pilus biogenesis and efficient plasmid transfer. The cyclic nature of the pilin could stabilize the pilus and may explain the high incidence of IncH plasmid dissemination.
-
Journal articleYoun T, Kim G, Hariharan P, et al., 2025,
Improved pendant-bearing glucose-neopentyl glycols for membrane protein stability
, Bioconjugate Chemistry, Vol: 36, Pages: 707-717, ISSN: 1043-1802Membrane proteins are biologically and pharmaceutically significant, and determining their 3D structures requires a membrane-mimetic system to maintain protein stability. Detergent micelles are widely used as membrane mimetics; however, their dynamic structures often lead to the denaturation and aggregation of encapsulated membrane proteins. To address the limitations of classical detergents in stabilizing membrane proteins, we previously reported a class of glucose-neopentyl glycols (GNGs) and their pendant-bearing versions (P-GNGs), several of which proved more effective than DDM in stabilizing membrane proteins. In this study, we synthesized additional GNG derivatives by varying the lengths of the pendant (P-GNGs), and by introducing hemifluorinated pendants to the GNG scaffold (fluorinated pendant-bearing GNGs or FP-GNGs). The synthetic flexibility of the GNG chemical architecture allowed us to create a diverse range of derivatives, essential for the effective optimization of detergent properties. When tested with two model membrane proteins (a transporter and a G-protein coupled receptor (GPCR)), most of the new (F)P-GNGs demonstrated superior stabilization of these membrane proteins compared to DDM, the original GNG (OGNG)), and a previously developed P-GNG (i.e., GNG-3,14). Notably, several P-GNGs synthesized in this study were as effective as or even better than lauryl maltose neopentyl glycol (LMNG) in stabilizing a human GPCR, beta2 adrenergic receptor (β2AR). Enhanced protein stability was particularly observed for the P-GNGs with a butyl (C4) or pentyl (C5) pendant, indicating that these pendant sizes are optimal for membrane protein stability. The volumes of these pendants appear to minimize the empty spaces in the micelle interiors, thereby enhancing detergent-detergent interactions in micelles complexed with the membrane proteins. Additionally, we identified one FP-GNG that was more efficient at extracting the transporter and more effective at st
-
Journal articleSadaf A, Yun HS, Lee H, et al., 2025,
Multiple pendants-bearing triglucosides for membrane protein studies: effects of pendant length and number on micelle interior hydration and protein stability
, Biomacromolecules, Vol: 26, Pages: 2565-2579, ISSN: 1525-7797Membrane proteins play central roles in cell physiology and are the targets of over 50% of FDA-approved drugs. In the present study, we prepared single alkyl-chained triglucosides decorated with multiple pendants, designated multiple pendant-bearing glucosides (MPGs), to enhance membrane protein stability. The new detergents feature two and four pendants of varying size at the hydrophilic–lipophilic interfaces, designated MPG-Ds and MPG-Ts, respectively. When tested with model membrane proteins, including the human adrenergic receptor (β2AR), the tetra-pendant-bearing MPGs (MPG-Ts) demonstrated superior performance compared to the dipendant analogs (MPG-Ds) and the gold standard DDM. All-atom molecular dynamics (MD) simulations results reveal that the four-pendant configuration of this detergent is remarkably effective in excluding water from the hydrophobic micelle interiors compared to the dipendant MPGs and DDM, an unprecedented feature of this new detergent. Our findings provide a novel strategy for designing water-resistant detergents, advancing the field of membrane protein research.
-
Journal articleZhang Y, Deveikis M, Qiu Y, et al., 2025,
Optimizing Protein Production in the One-Pot PURE System: Insights into Reaction Composition and Expression Efficiency
, ACS SYNTHETIC BIOLOGY, Vol: 14, Pages: 1496-1508, ISSN: 2161-5063- Cite
- Citations: 3
-
Journal articleZacharopoulou M, Seetaloo N, Ross J, et al., 2025,
Local Ionic Conditions Modulate the Aggregation Propensity and Influence the Structural Polymorphism of α-Synuclein
, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 147, Pages: 13131-13145, ISSN: 0002-7863- Cite
- Citations: 3
-
Journal articleFeleke R, Jogaudaite S, Velentza-Almpani E, et al., 2025,
Seeding-competent early tau multimers are associated with cell type-specific transcriptional signatures
, Acta Neuropathologica, Vol: 149, ISSN: 1432-0533The initial molecular alterations of Alzheimer’s disease (AD) are unknown. Established AD is characterized by profound structural and transcriptional alterations in the human brain, with the hallmark neuropathological features being beta-amyloid (Aβ) accumulation in senile plaques and hyperphosphorylated fibrillar tau in neurofibrillary tangles (NFTs). Previous evidence indicates that tau multimerization into small aggregates is one of the earliest molecular alterations, anticipating the accumulation of hyperphosphorylated tau in NFTs. In this study, we investigated the seeding capacity of these early small tau multimers and the transcriptional changes associated with them, aiming to unveil early pathogenic processes in AD-type tau pathology. Early tau multimers visualized with tau proximity ligation assay (tau-PLA) in the post-mortem temporal cortex demonstrated high seeding activity detected by real-time quaking-induced conversion (RT-QuIC) assay and induction of aggregates in a tau biosensor cell line. Using single-nucleus transcriptomics, we showed that brain tissue harboring seeding-competent early tau multimers, but without significant NFT pathology, is associated with substantial gene expression alterations across diverse cell types when compared to control tissue lacking either multimers or NFTs. Differentially expressed genes, such as APP, MAPT, and PSEN1, exhibited significant enrichment of AD heritability in up-regulated genes within excitatory neurons, astrocytes, and oligodendrocytes. Pseudotime analysis exposed a positive correlation between the progression of tau pathology and the expression of genes marking reactive astrocytes. In summary, our results support the hypothesis that seeding-competent tau multimerization may initiate AD-type tau pathology cascades before the accumulation of tau in NFTs. This research contributes valuable insights into the early molecular events associated with AD, with implications for future diagnostic and the
-
Journal articleAlzheimer M, Froschauer K, Svensson SL, et al., 2025,
Functional genomics of Campylobacter -host interactions in an intestinal tissue model reveals a small lipoprotein essential for flagellar assembly.
, bioRxivCampylobacter jejuni is currently the most common cause of bacterial gastroenteritis worldwide. However, its genome provides few clues about how it interacts with the host. Moreover, infection screens have often been limited to classical cell culture or animal models. To identify C. jejuni genes involved in host cell interactions, we applied transposon sequencing in a humanized 3D intestinal infection model based on tissue engineering. This revealed key proteins required for host cell adherence and/or internalization, including an Rrf2 family transcriptional regulator as well as three so far uncharacterized genes ( pflC / Cj1643 , pflD / Cj0892c , pflE / Cj0978c ), which we demonstrate to encode factors essential for motility. Deletion mutants of pflC / D / E are non-motile but retain intact, paralysed flagella filaments. We demonstrate that two of these newly identified motility proteins, PflC and PflD, are components of the C. jejuni 's periplasmic disk structures of the high torque motor. The third gene, pflE , encodes a small protein of only 57 aa. Using CryoET imaging we uncovered that the small protein has a striking effect on motor biogenesis, leading to a complete loss of the flagellar disk and motor structures upon its deletion. While PflE does not appear to be a structural component of the motor itself, our data suggests that it is a lipoprotein and supports localization of the main basal disk protein FlgP, which is the first assembly step of the flagellar disk structure. Despite being annotated as a lipoprotein, we find that C. jejuni FlgP instead relies on PflE for its association with the outer membrane. Overall, our genome-wide screen revealed novel C. jejuni host interaction factors including a transcriptional regulator as well as two structural components and a small protein crucial for biogenesis of the C. jejuni high torque flagella motor. Since the flagella machinery is a critical virulence determining factor for C. jejuni , our work demonstrates
-
Journal articleZhang C, Ning Z, Gong Z, et al., 2025,
Uncovering the Molecular Stacking Patterns and Tuning Fluorescence Properties of Organic Molecular Crystals through Cocrystallization
, CRYSTAL GROWTH & DESIGN, Vol: 25, Pages: 2465-2475, ISSN: 1528-7483- Cite
- Citations: 2
-
Journal articleRimle L, Phillips BP, Barra IMCC, et al., 2025,
A splendid molecular factory: De-and reconstruction of the mammalian respiratory chain
, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 122, ISSN: 0027-8424- Cite
- Citations: 1
-
Journal articleBeeby M, Daum B, 2025,
How Does the Archaellum Work?
, BIOMOLECULES, Vol: 15 -
Journal articleChen N, Ning Z, Gong Z, et al., 2025,
Realizing Aggregation-Induced Emission Improvement and Multistimulus-Responsive Reversible Fluorescence Switching through Multicomponent Crystals
, CRYSTAL GROWTH & DESIGN, Vol: 25, Pages: 2099-2109, ISSN: 1528-7483- Cite
- Citations: 4
-
Journal articleGrossmann Q, Saenz-Cavazos PA, Ferru N, et al., 2025,
Measuring and Modeling Water and Carbon Dioxide Adsorption on Amine Functionalized Alumina under Direct Air Capture Conditions
, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, Vol: 64, Pages: 7165-7175, ISSN: 0888-5885- Cite
- Citations: 2
-
Journal articleEhsan M, Ghani L, Lan B, et al., 2025,
Unsymmetric triazine‐based triglucoside detergents for membrane protein stability
, ChemBioChem: a European journal of chemical biology, Vol: 26, ISSN: 1439-4227Membrane proteins play a crucial role in a variety of biological processes and are key targets for pharmaceutical development. Structural studies of membrane proteins provide molecular insights into the mechanisms of these processes and are essential for effective drug discovery. Historically, these studies have relied on solubilization of the target protein using detergents, but conventional detergents often fail to maintain the stability of challenging membrane proteins. To address this issue, there is a need to develop novel detergents with enhanced protein stabilization properties. In this study, we synthesized unsymmetric variants of recently reported tris(hydroxymethyl)aminomethane(TRIS)-linker-bearing triazine-based triglucosides (TTGs) by incorporating two different alkyl chains (long and short) into the detergent structure. When tested with model membrane proteins, including a G protein-coupled receptor, TTG-8,12 demonstrated superior efficacy in stabilizing membrane proteins compared to the original TTGs and the gold standard detergents DDM/LMNG. These results suggest that detergent unsymmetry is an important concept for improving detergent performance and unsymmetric detergents such as TTG-8,12 hold significant potential for advancing membrane protein structural studies.
-
Thesis dissertationErrington E, 2025,
Life Cycle Assessment of Silica-derived Adsorbents for Wastewater Treatment
Current trends in wastewater pollution are inconsistent with long-term sustainable growth. This is being exacerbated by increases in the presence of emerging wastewater pollutants (EWPs), which existing treatment approaches are often not well-equipped to handle.Silica-Based adsorbent materials (SBAMs) are one technological solution being investigated as a treatment for EWPs. This is for many reasons, including the desirable material properties of silica, ease of manufacturability, and the ability to undergo surface chemistry modifications – all of which enable SBAMs to be tuned to treat individual pollutants effectively. However, the environmental impact (EI) of producing and using SBAMs is still poorly understood.This work addresses gaps in understanding for the EI of SBAMs and intermediate materials used in their manufacture. This is done by using a life cycle assessment (LCA) approach, supported by material and energy use estimates developed from a mixture of literature review (academic and patents), process design modelling, and laboratory experimentation. The utility of this understanding is then demonstrated by a case-study of the EI of using SBAMs to recover vegetable oils - an example source of “Fat, oil and Grease” EWP.Results of the work provide new predictions for the EI of a range of materials used in SBAM manufacture, including: 1) silica substrates, 2) surface chemistry modifiers, 3) surface-modified SBAMs, and 4) associated intermediates (e.g. organic surfactants, silicon metals, and chlorosilanes). A major finding is the importance of silica precursor choice for the EI of silica substrates, which accounts for between 69 and 100% of the EI of commercial silica substrates considered across several EI categories. Study also suggests that precursor choice can drive large changes in the absolute EI of SBAM products (e.g. 4 to 92 kg-CO2eq/kg) via wider effects on wider process design. Nonethless, it is shown that emerging SBAM substrates
-
Journal articleNaskar S, Merino A, Espadas J, et al., 2025,
Mechanism for Vipp1 spiral formation, ring biogenesis, and membrane repair
, Nature Structural and Molecular Biology, Vol: 32, Pages: 571-584, ISSN: 1545-9993The ESCRT-III-like protein Vipp1 couples filament polymerization with membrane remodeling. It assembles planar sheets as well as 3D rings and helical polymers, all implicated in mitigating plastid-associated membrane stress. The architecture of Vipp1 planar sheets and helical polymers remains unknown, as do the geometric changes required to transition between polymeric forms. Here we show how cyanobacterial Vipp1 assembles into morphologically-related sheets and spirals on membranes in vitro. The spirals converge to form a central ring similar to those described in membrane budding. Cryo-EM structures of helical filaments reveal a close geometric relationship between Vipp1 helical and planar lattices. Moreover, the helical structures reveal how filaments twist—a process required for Vipp1, and likely other ESCRT-III filaments, to transition between planar and 3D architectures. Overall, our results provide a molecular model for Vipp1 ring biogenesis and a mechanism for Vipp1 membrane stabilization and repair, with implications for other ESCRT-III systems.
-
Journal articleQi M, Taunt H, Bečková M, et al., 2025,
Enhancing the production of chlorophyll f in the cyanobacterium Synechocystis sp. PCC 6803
, Physiologia Plantarum, Vol: 177, ISSN: 0031-9317One potential approach to improve the productivity of cyanobacteria and microalgae is to enhance photosynthetic efficiency by introducing far-red absorbing pigment molecules (such as chlorophylls f and d) into the photosynthetic apparatus to expand the range of photosynthetically active radiation. We have shown previously that expressing the ChlF subunit of Chroococcidiopsis thermalis PCC 7203 in the model cyanobacterium Synechocystis sp. PCC 6803 (Syn6803) is sufficient to drive the production of chlorophyll f (Chl f), but only to low levels (0.24% Chl f/Chl a). By using the strong Pcpc560 promoter and an N-terminal truncated derivative of ChlF, we have been able to increase the yield of Chl f in white light by over 30-fold to about 8.2% Chl f/Chl a, close to the level displayed by far-red photoacclimated C. thermalis 7203. Additionally, we demonstrate that ChlF from Fisherella thermalis PCC 7521, like ChlF from C. thermalis 7203, assembles into a variant of the monomeric photosystem II (PSII) core complex termed the super-rogue PSII complex when expressed in Syn6803. This contrasts with the originally reported formation of a ChlF homodimeric complex in Synechococcus sp. PCC 7002. Overall, our work is an important starting point for mechanistic and structural studies of super-rogue PSII and for incorporating Chl f into the photosynthetic apparatus of Syn6803.
-
Journal articleYang D, Yang Y, Wong T, et al., 2025,
Solution-processable polymer membranes with hydrophilic subnanometre pores for sustainable lithium extraction
, nature water, Vol: 3, Pages: 319-333, ISSN: 2731-6084Membrane-based separation processes hold great promise for sustainable extraction of lithium from brines for the rapidly expanding electric vehicle industry and renewable energy storage. However, it remains challenging to develop high-selectivity membranes that can be upscaled for industrial processes. Here we report solution-processable polymer membranes with subnanometre pores with excellent ion separation selectivity in electrodialysis processes for lithium extraction. Polymers of intrinsic microporosity incorporated with hydrophilic functional groups enable fast transport of monovalent alkali cations (Li+, Na+ and K+) while rejecting relatively larger divalent ions such as Mg2+. The polymer of intrinsic microporosity membranes surpasses the performance of most existing membrane materials. Furthermore, the membranes were scaled up and integrated into an electrodialysis stack, demonstrating excellent selectivity in simulated salt-lake brines. This work will inspire the development of selective membranes for a wide range of sustainable separation processes critical for resource recovery and a global circular economy.
-
Thesis dissertationZhang B, 2025,
Structural studies on bacterial enhancer binding proteins HrpR-HrpS and their regulations during sigma-54 dependent bacterial transcription initiation
Transcription is the process of unwinding double stranded DNA (dsDNA) and using one strand as template to make copies of RNA polymers. Transcription requires a protein complex called RNA polymerase (RNAP). Transcription initiation requires RNAP to be located correctly on DNA. In bacteria, this is done by factors, which recognise specific regions called promoter and create the initial opening on the hydrogen bonded dsDNA to allow transcription to begin. A special member of sigma family 54 is able to recruit RNAP to the promoter, however, does not spontaneously initiate transcription. Instead, it requires additional activators called bacterial enhancer binding proteins (bEBPs) which bind DNA remotely upstream. By DNA looping, bEBPs interact with 54 downstream to facilitate the initial opening of dsDNA, subsequently activating transcription. bEBP-mediated transcription is extensively regulated to allow specific genes expression in response to signals such as host infection, stress response, starvation. In plant pathogen Pseudomonas syringae, genes associated with host infection are activated by HrpR and HrpS, bEBPs that uniquely function as heterohexamer upon activation. Their bEBP functions are found to be inhibited by HrpV and activated by HrpG, through unknown mechanism. Using cryo-EM, we characterised the structure of HrpRS in complex with promoter DNA, explaining the sequence-specific interaction by bEBP and the underlying roles of upstream DNA in promoting hexamer assembly and 54 interaction. Our models also provide insights into the selective advantages of heterohexameric arrangement over other bEBPs. Lastly, we presented data characterising the HrpV inhibition and the HrpG activation, explaining the underlying mechanisms in regulating bacterial pathogenesis.
-
Journal articleChen T, Hojka M, Davey P, et al., 2025,
Engineering Rubisco condensation in chloroplasts to manipulate plant photosynthesis
, Plant Biotechnology Journal, ISSN: 1467-7644 -
Journal articleYu C, Zheng J, Zhang Y, et al., 2025,
Towards sustainable spirulina farming: Enhancing productivity and biosafety with a salinity-biostimulants strategy
, BIORESOURCE TECHNOLOGY, Vol: 419, ISSN: 0960-8524 -
Journal articleKarde V, Khala M, Kisuka F, et al., 2025,
A review of dry powder coating: techniques, theory, and applications
, KONA Powder and Particle Journal, Vol: 43, Pages: 93-116, ISSN: 0288-4534Dry powder coating, characterised by the blending of poorly flowing powders with finer coating powders to optimise flowability, represents a sophisticated and evolving approach to powder processing. The optimisation of this method involves precise formulation, carefully combining powders with different particle properties to achieve a desirable blend aimed at enhancing the flow characteristics during the application process. Over the last decade, this field has witnessed increasing activity, focusing on key mixing parameters, such as mixer type and mixing power, as well as understanding the influence of constituent powder characteristics, including size ratio, density, and cohesion. Various techniques have been used to assess the flowability improvement or quantify the degree of coating. This review aims to provide a comprehensive exploration of the literature on powder coating research, highlighting its significance in both academic research and industrial applications. This paper discusses current coating analysis techniques using state-of-the-art equipment and reviews recent findings, particularly the nascent attempts to establish regime maps for dry powder coating.
-
Journal articleGosiamemang T, V Law R, Heng JYY, 2025,
Effects of base catalyst on the physicochemical properties and surface reactivity of silica nanoparticles
, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, Vol: 707, ISSN: 0927-7757 -
Journal articleJonnerby J, Fenn J, Hakki S, et al., 2025,
Inferring transmission risk of respiratory viral infection from the viral load kinetics of SARS-CoV-2, England, 2020 to 2021 and influenza A virus, Hong Kong, 2008 to 2012
, Eurosurveillance, Vol: 30, ISSN: 1560-7917BackgroundInfectiousness of respiratory viral infections is quantified as plaque forming units (PFU), requiring resource-intensive viral culture that is not routinely performed. We hypothesised that RNA viral load (VL) decline time (e-folding time) in people might serve as an alternative marker of infectiousness.AimThis study’s objective was to evaluate the association of RNA VL decline time with RNA and PFU VL area under the curve (AUC) and transmission risk for SARS-CoV-2 and influenza A virus.MethodsIn SARS-CoV-2 and influenza A virus community cohorts, viral RNA was quantified by reverse transcription quantitative PCR in serial upper respiratory tract (URT)-samples collected within households after an initial household-member tested positive for one virus. We evaluated correlations between RNA VL decline time and RNA and PFU-VL AUC. Associations between VL decline time and transmission risk in index-contact pairs were assessed.ResultsIn SARS-CoV-2 cases, we observed positive correlations between RNA VL decline time and RNA and PFU VL AUC with posterior probabilities 1 and 0.96 respectively. In influenza A cases a positive correlation between RNA VL decline time and RNA VL AUC was observed, with posterior probability of 0.87. Index case VL decline times one standard deviation above the cohort-mean showed a relative increase in secondary attack rates of 39% (95% credible interval (CrI): −6.9 to 95%) for SARS-CoV-2 and 25% (95% CrI: −11 to 71%) for influenza A virus.ConclusionWe identify VL decline time as a potential marker of infectiousness and transmission risk for SARS-CoV-2 and influenza A virus. Early ascertainment of VL kinetics as part of surveillance of new viruses or variants could inform public health decision making.
-
Conference paperXu V, Barritt J, Wake M, et al., 2025,
Structural study of adeno-associated virus replication protein 40 and its role in DNA encapsidation
, 60th Annual Meeting of the Biophysical-Society, Publisher: CELL PRESS, ISSN: 0006-3495 -
Journal articleGrundling A, Brogan AP, James MJ, et al., 2025,
PgpP is a broadly conserved phosphatase required for phosphatidylglycerol lipid synthesis
, Proceedings of the National Academy of Sciences of USA, Vol: 122, ISSN: 0027-8424The cytoplasmic membrane of bacteria is composed of a phospholipid bilayer made up of a diverse set of lipids. Phosphatidylglycerol (PG) is one of the principal constituents and its production is essential for growth in many bacteria. All the enzymes required for PG biogenesis in Escherichia coli have been identified and characterized decades ago. However, it has remained poorly understood how gram-positive bacteria perform the terminal step in the pathway that produces this essential lipid. In E. coli, this reaction is mediated by three functionally redundant phosphatases that convert phosphatidylglycerophosphate (PGP) into PG. Here, we show that homologs of these enzymes in Bacillus subtilis are not required for PG synthesis. Instead, we identified a previously uncharacterized B. subtilis protein, YqeG (renamed PgpP), as an essential enzyme required for the conversion of PGP into PG. Expression of B. subtilis or Staphylococcus aureus PgpP in E. coli lacking all three Pgp enzymes supported the growth of the strain. Furthermore, depletion of PgpP in B. subtilis led to growth arrest, reduced membrane lipid staining, and accumulation of PGP. PgpP is broadly conserved among Firmicutes and Cyanobacteria. Homologs are also present in yeast mitochondria and plant chloroplasts, suggesting that this widely distributed enzyme has an ancient origin. Finally, evidence suggests that PgpP homologs are essential in many gram-positive pathogens and thus the enzyme represents an attractive target for antibiotic development.
-
Journal articleBetterle N, Gasparotto E, Battagini E, et al., 2025,
Engineering of the fast-growing cyanobacterium Synechococcus PCC 11901 for the synthesis of astaxanthin
, Biotechnology for Biofuels and Bioproducts -
Journal articleSiddiqui A, Iqbal M, Ali A, et al., 2025,
Harnessing the potential of chloroplast-derived expression elements for enhanced production of cellulases in Escherichia coli
, PeerJ, Vol: 13, ISSN: 2167-8359Thermophilic cellulases can play a crucial part in the efficient breakdown of cellulose—a major component of lignocellulosic plant biomass, however, their commercial production needs simple and robust biomanufacturing biosystems. In this study, two cellulases (β-glucosidase and endoglucanase) were heterologously expressed in Escherichia coli under a chloroplast-derived constitutive promoter and expression-enhancing terminator. The genes encoding the cellulases were sourced from a thermophilic bacterium Thermotoga maritima to exploit their industrially needed thermotolerance potential. The codon-optimized gene sequences were synthesized and placed under a tobacco chloroplast 16S rRNA promoter (Prrn), along with the 5′ UTR (untranslated region) from gene 10 of phage T7 (T7g10). A six-residue long histidine tag (His6-tag) was attached to the N-terminus for protein detection. A high-level of expression of β-glucosidase and endoglucanase in E. coli was recorded from the chloroplast promoter and terminator. Furthermore, the activity assays confirmed that the recombinant enzymes maintained their activity at elevated temperatures. Thermostability analysis showed that recombinant enzymes retained their thermotolerance even after being expressed in a non-native host. Where, β-glucosidase and endoglucanase showed their optimum activities at 90 °C and 100 °C, respectively. Examination of the 3D structures of T. maritima cellulases revealed differential ionic interactions contributing to this high degree of thermotolerance. The study highlights the feasibility of producing thermostable versions of recombinant enzymes in E. coli at high levels. Our finding underscores the potential of this approach to meet industrial demands for efficient enzyme production employing E. coli as a robust biomanufacturing platform.
-
Journal articleLombardi L, Granger L, Shattock R, et al., 2025,
Advancements in loop cyclization approaches for enhanced peptide therapeutics for targeting protein–protein interactions
, Journal of Organic Chemistry, Vol: 90, Pages: 1467-1477, ISSN: 0022-3263Protein–protein interactions (PPIs) are pivotal in regulating cellular functions and life processes, making them promising therapeutic targets in modern medicine. Despite their potential, developing PPI inhibitors poses significant challenges due to their large and shallow interfaces that complicate ligand binding. This study focuses on mimicking peptide loops as a strategy for PPI inhibition, utilizing synthetic peptide loops for replicating critical binding regions. This work explores turn-inducing elements and highlights the importance of proline in promoting favorable conformations for lactamization, yielding high-purity cyclic peptides. Notably, our one-pot method offers enhanced versatility and represents a robust strategy for efficient and selective macrolactamization, expanding the scope of peptide synthesis methodologies. This approach, validated through the synthesis of AAV capsid-derived loops, offers a robust platform for developing peptide-based therapeutics and highlights the potential of peptide macrocycles in overcoming PPI drug discovery challenges and advancing the development of new therapeutics.
-
Journal articleCarver A, Yu T-Y, Yates LA, et al., 2025,
Molecular basis of FIGNL1 in dissociating RAD51 from DNA and chromatin
, Science, Vol: 387, Pages: 426-431, ISSN: 0036-8075Maintaining genome integrity is an essential and challenging process. RAD51 recombinase, the central player of several crucial processes in repairing DNA and protecting genome integrity, forms filaments on DNA, which are tightly regulated. One of these RAD51 regulators is FIGNL1, that prevents persistent RAD51 foci without or after DNA damage and genotoxic chromatin association in cells. The cryogenic electron microscopy structure of FIGNL1 in complex with RAD51 reveals that FIGNL1 forms a non-planar hexamer and RAD51 N terminus enclosure in the FIGNL1 hexamer pore. Mutations in pore loop or catalytic residues of FIGNL1 render it defective in filament disassembly and are lethal in mouse embryonic stem cells. Our study reveals a unique mechanism for removing RAD51 from bound substrates and provides the molecular basis for FIGNL1 in maintaining genome stability.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.