Evolving evidence suggests that nicotine may contribute to impaired asthma control by stimulating expression of nerve growth factor (NGF), a neurotrophin associated with airway remodeling and airway hyperresponsiveness. We explored the hypothesis that nicotine increases NGF by reducing lung fibroblast (LF) microRNA-98 (miR-98) and PPARγ levels, thus promoting airway remodeling. Levels of NGF, miR-98, PPARγ, fibronectin 1 (FN1), endothelin-1 (EDN1, herein referred to as ET-1), and collagen (COL1A1 and COL3A1) were measured in human LFs isolated from smoking donors, in mouse primary LFs exposed to nicotine (50 μg/ml), and in whole lung homogenates from mice chronically exposed to nicotine (100 μg/ml) in the drinking water. In selected studies, these pathways were manipulated in LFs with miR-98 inhibitor (anti-miR-98), miR-98 overexpression (miR-98 mimic), or the PPARγ agonist rosiglitazone. Compared with unexposed controls, nicotine increased NGF, FN1, ET-1, COL1A1, and COL3A1 expression in human and mouse LFs and mouse lung homogenates. In contrast, nicotine reduced miR-98 levels in LFs in vitro and in lung homogenates in vivo. Treatment with anti-miR-98 alone was sufficient to recapitulate increases in NGF, FN1, and ET-1, whereas treatment with a miR-98 mimic significantly suppressed luciferase expression in cells transfected with a luciferase reporter linked to the putative seed sequence in the NGF 3'UTR and also abrogated nicotine-induced increases in NGF, FN1, and ET-1 in LFs. Similarly, rosiglitazone increased miR-98 and reversed nicotine-induced increases in NGF, FN1, and ET-1. Taken together, these findings demonstrate that nicotine-induced increases in NGF and other markers of airway remodeling are negatively regulated by miR-98.

The molecular mechanisms of reduced frataxin (FXN) expression in Friedreich's ataxia (FRDA) are linked to epigenetic modification of the FXN locus caused by the disease-associated GAA expansion. Here, we identify that SUV4-20 histone methyltransferases, specifically SUV4-20 H1, play an important role in the regulation of FXN expression and represent a novel therapeutic target. Using a human FXN–GAA–Luciferase repeat expansion genomic DNA reporter model of FRDA, we screened the Structural Genomics Consortium epigenetic probe collection. We found that pharmacological inhibition of the SUV4-20 methyltransferases by the tool compound A-196 increased the expression of FXN by ∼1.5-fold in the reporter cell line. In several FRDA cell lines and patient-derived primary peripheral blood mononuclear cells, A-196 increased FXN expression by up to 2-fold, an effect not seen in WT cells. SUV4-20 inhibition was accompanied by a reduction in H4K20me2 and H4K20me3 and an increase in H4K20me1, but only modest (1.4–7.8%) perturbation in genome-wide expression was observed. Finally, based on the structural activity relationship and crystal structure of A-196, novel small molecule A-196 analogs were synthesized and shown to give a 20-fold increase in potency for increasing FXN expression. Overall, our results suggest that histone methylation is important in the regulation of FXN expression and highlight SUV4-20 H1 as a potential novel therapeutic target for FRDA.

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Histone recognition by “reader” modules serves as a fundamental mechanism in epigenetic regulation. Previous studies have shown that Spindlin1 is a reader of histone H3K4me3 as well as “K4me3-R8me2a” and promotes transcription of rDNA or Wnt/TCF4 target genes. Here we show that Spindlin1 also acts as a potent reader of histone H3 “K4me3-K9me3/2” bivalent methylation pattern. Calorimetric titration revealed a binding affinity of 16 nm between Spindlin1 and H3 “K4me3-K9me3” peptide, which is one to three orders of magnitude stronger than most other histone readout events at peptide level. Structural studies revealed concurrent recognition of H3K4me3 and H3K9me3/2 by aromatic pockets 2 and 1 of Spindlin1, respectively. Epigenomic profiling studies showed that Spindlin1 colocalizes with both H3K4me3 and H3K9me3 peaks in a subset of genes enriched in biological processes of transcription and its regulation. Moreover, the distribution of Spindlin1 peaks is primarily associated with H3K4me3 but not H3K9me3, which suggests that Spindlin1 is a downstream effector of H3K4me3 generated in heterochromatic regions. Collectively, our work calls attention to an intriguing function of Spindlin1 as a potent H3 “K4me3-K9me3/2” bivalent mark reader, thereby balancing gene expression and silencing in H3K9me3/2-enriched regions.

DNA polymerases are today used throughout scientific research, biotechnology, and medicine, in part for their ability to interact with unnatural forms of DNA created by synthetic biologists. Here especially, natural DNA polymerases often do not have the “performance specifications” needed for transformative technologies. This creates a need for science-guided rational (or semi-rational) engineering to identify variants that replicate unnatural base pairs (UBPs), unnatural backbones, tags, or other evolutionarily novel features of unnatural DNA. In this review, we provide a brief overview of the chemistry and properties of replicative DNA polymerases and their evolved variants, focusing on the Klenow fragment of Taq DNA polymerase (Klentaq). We describe comparative structural, enzymatic, and molecular dynamics studies of WT and Klentaq variants, complexed with natural or noncanonical substrates. Combining these methods provides insight into how specific amino acid substitutions distant from the active site in a Klentaq DNA polymerase variant (ZP Klentaq) contribute to its ability to replicate UBPs with improved efficiency compared with Klentaq. This approach can therefore serve to guide any future rational engineering of replicative DNA polymerases.

RecQ family helicases are highly conserved from bacteria to humans and have essential roles in maintaining genome stability. Mutations in three human RecQ helicases cause severe diseases with the main features of premature aging and cancer predisposition. Most RecQ helicases shared a conserved domain arrangement which comprises a helicase core, an RecQ C-terminal domain, and an auxiliary element helicase and RNaseD C-terminal (HRDC) domain, the functions of which are poorly understood. In this study, we systematically characterized the roles of the HRDC domain in E. coli RecQ in various DNA transactions by single-molecule FRET. We found that RecQ repetitively unwinds the 3'-partial duplex and fork DNA with a moderate processivity and periodically patrols on the ssDNA in the 5'-partial duplex by translocation. The HRDC domain significantly suppresses RecQ activities in the above transactions. In sharp contrast, the HRDC domain is essential for the deep and long-time unfolding of the G4 DNA structure by RecQ. Based on the observations that the HRDC domain dynamically switches between RecA core- and ssDNA-binding modes after RecQ association with DNA, we proposed a model to explain the modulation mechanism of the HRDC domain. Our findings not only provide new insights into the activities of RecQ on different substrates but also highlight the novel functions of the HRDC domain in DNA metabolisms.

Rhodopsin is a canonical class A photosensitive G protein–coupled receptor (GPCR), yet relatively few pharmaceutical agents targeting this visual receptor have been identified, in part due to the unique characteristics of its light-sensitive, covalently bound retinal ligands. Rhodopsin becomes activated when light isomerizes 11-cis-retinal into an agonist, all-trans-retinal (ATR), which enables the receptor to activate its G protein. We have previously demonstrated that, despite being covalently bound, ATR can display properties of equilibrium binding, yet how this is accomplished is unknown. Here, we describe a new approach for both identifying compounds that can activate and attenuate rhodopsin and testing the hypothesis that opsin binds retinal in equilibrium. Our method uses opsin-based fluorescent sensors, which directly report the formation of active receptor conformations by detecting the binding of G protein or arrestin fragments that have been fused onto the receptor's C terminus. We show that these biosensors can be used to monitor equilibrium binding of the agonist, ATR, as well as the noncovalent binding of β-ionone, an antagonist for G protein activation. Finally, we use these novel biosensors to observe ATR release from an activated, unlabeled receptor and its subsequent transfer to the sensor in real time. Taken together, these data support the retinal equilibrium binding hypothesis. The approach we describe should prove directly translatable to other GPCRs, providing a new tool for ligand discovery and mutant characterization.

Pyruvate kinase muscle isoform 2 (PKM2) is a key glycolytic enzyme and transcriptional coactivator and is critical for tumor metabolism. In cancer cells, native tetrameric PKM2 is phosphorylated or acetylated, which initiates a switch to a dimeric/monomeric form that translocates into the nucleus, causing oncogene transcription. However, it is not known how these post-translational modifications (PTMs) disrupt the oligomeric state of PKM2. We explored this question via crystallographic and biophysical analyses of PKM2 mutants containing residues that mimic phosphorylation and acetylation. We find that the PTMs elicit major structural reorganization of the fructose 1,6-bisphosphate (FBP), an allosteric activator, binding site, impacting the interaction with FBP and causing a disruption in oligomerization. To gain insight into how these modifications might cause unique outcomes in cancer cells, we examined the impact of increasing the intracellular pH (pHi) from ∼7.1 (in normal cells) to ∼7.5 (in cancer cells). Biochemical studies of WT PKM2 (wtPKM2) and the two mimetic variants demonstrated that the activity decreases as the pH is increased from 7.0 to 8.0, and wtPKM2 is optimally active and amenable to FBP-mediated allosteric regulation at pHi 7.5. However, the PTM mimetics exist as a mixture of tetramer and dimer, indicating that physiologically dimeric fraction is important and might be necessary for the modified PKM2 to translocate into the nucleus. Thus, our findings provide insight into how PTMs and pH regulate PKM2 and offer a broader understanding of its intricate allosteric regulation mechanism by phosphorylation or acetylation.

Myosins generate force and motion by precisely coordinating their mechanical and chemical cycles, but the nature and timing of this coordination remains controversial. We utilized a FRET approach to examine the kinetics of structural changes in the force-generating lever arm in myosin V. We directly compared the FRET results with single-molecule mechanical events examined by optical trapping. We introduced a mutation (S217A) in the conserved switch I region of the active site to examine how myosin couples structural changes in the actin- and nucleotide-binding regions with force generation. Specifically, S217A enhanced the maximum rate of lever arm priming (recovery stroke) while slowing ATP hydrolysis, demonstrating that it uncouples these two steps. We determined that the mutation dramatically slows both actin-induced rotation of the lever arm (power stroke) and phosphate release (≥10-fold), whereas our simulations suggest that the maximum rate of both steps is unchanged by the mutation. Time-resolved FRET revealed that the structure of the pre– and post–power stroke conformations and mole fractions of these conformations were not altered by the mutation. Optical trapping results demonstrated that S217A does not dramatically alter unitary displacements or slow the working stroke rate constant, consistent with the mutation disrupting an actin-induced conformational change prior to the power stroke. We propose that communication between the actin- and nucleotide-binding regions of myosin assures a proper actin-binding interface and active site have formed before producing a power stroke. Variability in this coupling is likely crucial for mediating motor-based functions such as muscle contraction and intracellular transport.

RNA-protein interfaces control key replication events during the HIV-1 life cycle. The viral trans-activator of transcription (Tat) protein uses an archetypal arginine-rich motif (ARM) to recruit the host positive transcription elongation factor b (pTEFb) complex onto the viral trans-activation response (TAR) RNA, leading to activation of HIV transcription. Efforts to block this interaction have stimulated production of biologics designed to disrupt this essential RNA-protein interface. Here, we present four co-crystal structures of lab-evolved TAR-binding proteins (TBPs) in complex with HIV-1 TAR. Our results reveal that high-affinity binding requires a distinct sequence and spacing of arginines within a specific β2-β3 hairpin loop that arose during selection. Although loops with as many as five arginines were analyzed, only three arginines could bind simultaneously with major-groove guanines. Amino acids that promote backbone interactions within the β2-β3 loop were also observed to be important for high-affinity interactions. Based on structural and affinity analyses, we designed two cyclic peptide mimics of the TAR-binding β2-β3 loop sequences present in two high-affinity TBPs (KD values of 4.2 ± 0.3 and 3.0 ± 0.3 nm). Our efforts yielded low-molecular weight compounds that bind TAR with low micromolar affinity (KD values ranging from 3.6 to 22 μm). Significantly, one cyclic compound within this series blocked binding of the Tat-ARM peptide to TAR in solution assays, whereas its linear counterpart did not. Overall, this work provides insight into protein-mediated TAR recognition and lays the ground for the development of cyclic peptide inhibitors of a vital HIV-1 RNA-protein interaction.

Erythromycin-resistance methyltransferases are SAM dependent Rossmann fold methyltransferases that convert A2058 of 23S rRNA to m6 2A2058. This modification sterically blocks binding of several classes of antibiotics to 23S rRNA, resulting in a multidrug-resistant phenotype in bacteria expressing the enzyme. ErmC is an erythromycin resistance methyltransferase found in many Gram-positive pathogens, whereas ErmE is found in the soil bacterium that biosynthesizes erythromycin. Whether ErmC and ErmE, which possess only 24% sequence identity, use similar structural elements for rRNA substrate recognition and positioning is not known. To investigate this question, we used structural data from related proteins to guide site-saturation mutagenesis of key residues and characterized selected variants by antibiotic susceptibility testing, single turnover kinetics, and RNA affinity–binding assays. We demonstrate that residues in α4, α5, and the α5-α6 linker are essential for methyltransferase function, including an aromatic residue on α4 that likely forms stacking interactions with the substrate adenosine and basic residues in α5 and the α5-α6 linker that likely mediate conformational rearrangements in the protein and cognate rRNA upon interaction. The functional studies led us to a new structural model for the ErmC or ErmE-rRNA complex.

V. G. Lysov
Trans. Moscow Math. Soc. 83 (), 291-304.
Abstract, references and article information

A. I. Aptekarev and M. L. Yattselev
Trans. Moscow Math. Soc. 83 (), 251-268.
Abstract, references and article information

A. Kh. Khachatryan, Kh. A. Khachatryan and A. Zh. Narimanyan
Trans. Moscow Math. Soc. 83 (), 183-200.
Abstract, references and article information

A. V. Silantyev
Trans. Moscow Math. Soc. 83 (), 75-149.
Abstract, references and article information

A. G. Sergeev, A. Kh. Khachatryan and Kh. A. Khachatryan
Trans. Moscow Math. Soc. 83 (), 55-65.
Abstract, references and article information

N. R. Ikonomov and S. P. Suetin
Trans. Moscow Math. Soc. 83 (), 33-54.
Abstract, references and article information

A. P. Starovoitov and N. V. Ryabchenko
Trans. Moscow Math. Soc. 83 (), 15-31.
Abstract, references and article information

Minerals and Metals for a Low-Carbon Future: Implications for Developing Countries 30 October 2017 — 5:00PM TO 8:00PM Anonymous (not verified) 13 October 2017 Chatham House, London

This roundtable will explore two sides of minerals and metals for a low-carbon future - the growing demand for metals required for low-carbon technology and the technological and policy innovations that will be required to manage the carbon footprint of the mining sector and its wider energy and industrial linkages. Based around a presentation and scenarios developed by the World Bank, this roundtable discussion will assess which strategic metals will likely rise in demand in order to deliver a low-carbon future, before exploring the possible implications for resource-rich developing countries. In particular, what does a growing demand of minerals for a clean energy future mean for governments and industry, and how might developing countries benefit from this trend? What impact might growth of the mining sector have on a sustainable and climate-smart development? Can renewable energy and other clean tech innovations in the mining industry help reduce the carbon footprint of the sector and related industries, and under what circumstances? And how fit-for-purpose are current donor approaches to the mining sector in an increasingly carbon-constrained world?

Attendance at this event is by invitation only.

Fossil Fuels Expert Roundtable: Forecasting Forum 2018 12 February 2018 — 2:00PM TO 5:30PM Anonymous (not verified) 18 December 2017 Chatham House, London

This forum will present the latest thinking from senior researchers on the dynamics that will affect fossil fuels investment and markets in the year ahead. The first session will assess the various factors keeping oil and gas prices from bouncing back and will consider conditions and political developments that could influence markets in the year ahead. The second session will assess the future of the power sector and what this means for the fossil fuels industry.

Attendance at this event is by invitation only.

Korea's New Energy Policy and Implications for LNG Imports 3 October 2018 — 9:00AM TO 10:30AM Anonymous (not verified) 17 September 2018 Chatham House | 10 St James's Square | London | SW1Y 4LE

The new energy policy of Moon Jae-In’s administration aims to swing radically from coal and nuclear towards renewables and LNG for power generation. During the last 12 months the priority given to the expansion of renewable energy has been overwhelming and the support for the expansion of gas not as strong as many observers had expected. The 13th gas supply and demand plan announced in Spring 2018 confirmed the trend. Based on this projection, Professor K. Paik will discuss how this new energy policy will affect Korea’s LNG imports strategy and what are the implications of Korea’s northern policy towards this LNG supply strategy and pipeline gas imports to the Korean Peninsula.

Attendance at this event is by invitation only.

Realizing the Potential of Extractives for Industrial and Economic Development 18 October 2018 — 5:30PM TO 7:00PM Anonymous (not verified) 3 October 2018 Chatham House | 10 St James's Square | London | SW1Y 4LE

Over the past two decades, the extractives industries have risen in importance for many low- and middle- income countries their prospects for economic development and poverty reduction. During a period of rising commodities prices, the development of extractives became increasingly attractive to both governments and companies. There was - and remains - much discussion about their potential to support inclusive development.

However, there are also risks and uncertainties associated with the extractives industries and many things can, and do, go wrong. Fluctuations in commodity prices can be hard to manage and can lead to considerable fiscal pressures. In the longer-term, climate change and the various policy responses to this, will profoundly affect the extractives sector as renewables replace fossil fuels in the global energy mix.

Managing the extractives sectors will therefore remain highly challenging especially in low-income countries where institutions are often weak. This roundtable will bring together some of the foremost academics and practitioners working in the extractives industries and also in economic development to discuss a major new UNU-WIDER study Extractive Industries: The Management of Resources as a Driver of Sustainable Development.

Attendance at this event is by invitation only.

The Electric Vehicle Revolution: Impacts on Oil Economies and Industry 24 January 2019 — 8:15AM TO 9:45AM Anonymous (not verified) 3 December 2018 Chatham House | 10 St James's Square | London | SW1Y 4LE

Electric vehicle (EV) deployment is gathering pace: the Norwegian government thinks that EV subsidies will be unnecessary by 2025 as they reach parity with diesel and petrol vehicles.

China has stipulated that EVs comprise 12 per cent of vehicle sales by 2020 while more governments are committing to banning diesel and petrol vehicles.

These developments are expected to be replicated as urban air pollution rises up the political agenda while technological developments and falling costs have given rise to ambitious forecasts on the increase in the deployment of EVs and the demise of the internal combustion engine.

Considering this, the presentations and initial discussion focus on:

• The influence of new technologies on the automotive landscape, including autonomous vehicles.
• How the automotive and oil companies are adjusting their business models to accommodate and encourage the rise in EVs.
• The risks and opportunities for the deployment of EVs for incumbents and new market actors.
• The role of government for example in public procurement and infrastructure development.
• The potential for modal shift and its impact on oil demand.

The discussion then seeks to explore the need for benchmarks of change including data and metrics to understand the changing risk landscape and the implications for different actors.

Finally, the discussion focuses on the speed of transformation and what this means for existing and new market actors.

The Impact of Brexit on Energy Transformation in the UK and EU 28 March 2019 — 8:15AM TO 9:45AM Anonymous (not verified) 3 December 2018 Chatham House | 10 St James's Square | London | SW1Y 4LE

The UK’s decision to leave the EU will fundamentally reshape many of the UK’s policies and its relations with countries around the world. For energy and climate, the changes could be significant and will need to be managed carefully to secure ongoing investment, stable energy prices and ambitious climate objectives. The UK’s departure will also affect the balance of political support for climate and energy policies with the EU institutions and potentially impact upon regional initiatives.

This roundtable will discuss:

• The impact on the energy sector of Brexit during the transition period through until December 2020 including the operation of interconnectors and access to the Internal energy market, ongoing engagement in European research collaboration and the replacement of European financial resources.
• The possible opportunities and risks for the UK’s energy sector in 2021 and beyond.
• The implications of Brexit on the EU’s energy and climate policy.

The roundtable will discuss the role of the public and business in shaping the future deal as it will need to be ratified by the parliaments of all member states.

Attendance at this event is by invitation only.

Forecasting Forum 2019 29 January 2019 — 2:00PM TO 5:30PM Anonymous (not verified) 17 December 2018 Chatham House | 10 St James's Square | London | SW1Y 4LE

This annual forum, previously held as part of the Fossil Fuels Expert Roundtable but now re-branded under the Energy Transitions Roundtable, presents the latest thinking from the Energy, Environment and Research Department’s senior research team on the dynamics that will affect fossil fuels investment and markets in the year ahead. This year, the forum will have three sessions:

Session 1 | 14:05 - 15:00 | Climate Trends

In December, a ‘playbook’ to implement the 2015 Paris Agreement was agreed by 196 countries at the UN’s COP24 in Poland. Despite this success, challenges surrounding common reporting requirements, degree-pathways to pursue, increasing ambition and the implementation of NDCs still remain. In this session, Pete Betts, former Head of International Climate and Energy at the UK Department for Business, Energy, and Industrial Strategy, will reflect on developments in the climate agenda and what action should be taken both in the UK and internationally against the backdrop of Brexit.

Session 2 | 15:15 - 16:15 | An Outlook for Oil in 2019

The future of crude oil prices for 2019 is perhaps more uncertain than it has been for several years. Following a period between 2014-17 when over-supply banished geopolitics from influencing the oil price, the market appears to be struggling to price political risk. Recently the OPEC Plus agreement was renewed in an effort to curtail production and defend prices but its effectiveness is in question as the shale technology revolution in the US continues to add to global supply - but for how long? Meanwhile, US relations with Saudi Arabia remain uncertain in the aftermath of the murder of Jamal Khashoggi: how might Saudi oil policy unfold? Similarly, how might Iran respond to President Trump’s unilateral abrogation of the JCPOA agreement? In this session, Paul Stevens looks at the geopolitical factors that might influence crude oil prices in 2019.

Session 3 | 16:30 - 17:30 | An Outlook for Coal

The rapid phase-out of coal-fired power stations is crucial to the delivery of the goals of the Paris Agreement and to the safeguarding of clean air and water and public health. Some policy and economic developments show that the coal sector is in structural decline, and there is growing international momentum behind coal phase-out. At the same time, many of the largest coal trading countries and companies continue to argue the short-term profitability of the sector but at what cost? This session will explore the national and international risks that continued investment in coal present and the developments that could change this in the year ahead.

Attendance at this event is by invitation only.

The Global Implications of China's Energy Revolution 4 March 2019 — 9:00AM TO 10:30AM Anonymous (not verified) 7 February 2019 Chatham House | 10 St James's Square | London | SW1Y 4LE

Ten years ago, it would have been difficult to believe that China – the world’s largest greenhouse gas emitter – would be one of the global leaders in some elements of clean energy development and deployment. With increasing air pollution and predominantly coal-fired power generation fueled by a booming economy and population, China has had to rethink its approach to environmental protection and climate mitigation.

Strong government signalling and national policies have led to the construction of the world’s largest fleets, wind farms and solar photovoltaic arrays in an effort to reduce national GDP intensities of energy and CO2 emissions. How has the availability of large amounts of capital, and the number of state-owned companies with soft budgetary constraints, helped contribute to this?

Against this backdrop, this event will consider how China must re-evaluate its approach to energy security – coal made up the majority of the country’s energy in 2016, followed by oil, of which 65 per cent had to be imported – despite the country being one of the pioneers of renewable energy. This event will look at how, in delivering on its clean energy objectives, China could redefine the traditional energy security paradox and in fact become more resilient to previously overlooked vulnerabilities.

The Future of Food Post-Brexit 26 February 2019 — 9:00AM TO 10:30AM Anonymous (not verified) 7 February 2019 Chatham House | 10 St James's Square | London | SW1Y 4LE

For almost half a century, the UK’s food system – comprising the totality of food production, transport, manufacturing, retailing and consumption – has been intrinsically and intricately linked to its membership of the European Community and, subsequently, the EU. Arguably, for no other sectors are the challenges and opportunities of Brexit as extensive as they are for UK food and agriculture.

Reforming the UK’s food system won’t be easy. The tight Brexit timeline, the complexities of negotiations and the political pressure to secure new trade deals could lead to decisions that are poorly conceived and become near impossible to correct.

This event will explore the challenges of the UK’s ‘just in time’ food system which only maintains 5-10 days’ worth of groceries country-wide, what the impacts of structural changes will be post-Brexit such as longer inspections of food imports at the border and what the main priorities for policymakers should be in the event of a no-deal Brexit to ensure the country’s food-stock can satisfy demand.