A chemical probe to modulate human GID4 Pro/N-degron interactions.

The C-terminal to LisH (CTLH) complex is a ubiquitin ligase complex that recognizes substrates with Pro/N-degrons via its substrate receptor Glucose-Induced Degradation 4 (GID4), but its function and substrates in humans remain unclear. Here, we report PFI-7, a potent, selective and cell-active chemical probe that antagonizes Pro/N-degron binding to human GID4. Use of PFI-7 in proximity-dependent biotinylation and quantitative proteomics enabled the identification of GID4 interactors and GID4-regulated proteins. GID4 interactors are enriched for nucleolar proteins, including the Pro/N-degron-containing RNA helicases DDX21 and DDX50. We also identified a distinct subset of proteins whose cellular levels are regulated by GID4 including HMGCS1, a Pro/N-degron-containing metabolic enzyme. These data reveal human GID4 Pro/N-degron targets regulated through a combination of degradative and nondegradative functions. Going forward, PFI-7 will be a valuable research tool for investigating CTLH complex biology and facilitating development of targeted protein degradation strategies that highjack CTLH E3 ligase activity.

Structural insights into DNA recognition by the BEN domain of the transcription factor BANP.

The BEN domain-containing transcription factors regulate transcription by recruiting chromatin-modifying factors to specific chromatin regions via their DNA-binding BEN domains. The BEN domain of BANP has been shown to bind to a CGCG DNA sequence or an AAA-containing matrix attachment regions DNA sequence. Consistent with these in vivo observations, we identified an optimal DNA-binding sequence of AAATCTCG by protein binding microarray, which was also confirmed by our isothermal titration calorimetry and mutagenesis results. We then determined crystal structures of the BANP BEN domain in apo form and in complex with a CGCG-containing DNA, respectively, which revealed that the BANP BEN domain mainly used the electrostatic interactions to bind DNA with some base-specific interactions with the TC motifs. Our isothermal titration calorimetry results also showed that BANP bound to unmethylated and methylated DNAs with comparable binding affinities. Our complex structure of BANP-mCGCG revealed that the BANP BEN domain bound to the unmethylated and methylated DNAs in a similar mode and cytosine methylation did not get involved in binding, which is also consistent with our observations from the complex structures of the BEND6 BEN domain with the CGCG or CGmCG DNAs. Taken together, our results further elucidate the elements important for DNA recognition and transcriptional regulation by the BANP BEN domain-containing transcription factor.

Construction of Inorganic/Polymer Tandem Layer on Li Metal with Long-Term Stability by LiNO3 Concentration Gradient Electrolyte.

Metal electrode with long cycle life is decisive for the actual use of metal rechargeable batteries, while the dendrite growth and side reaction limit their cyclic stability. Herein, the construction of polymer and inorganic-rich SEI tandem layer structure on Li metal can be used for extraordinarily extending its cycle life is reported, which is generated by an in situ PVDF/LiF/LiNO3 (PLL) gel layer on the surface of Li metal with a chemically compatible ether solvent. The cycle life of Li//Li cells with the tandem layer structure is over 6000 h, six times longer than those with LiNO3 homogeneous electrolyte. It highlights the importance of LiNO3 concentration gradient electrolyte formed by the in situ PLL gel layer, in which highly concentrated LiNO3 is confined on the surface of Li metal to generate the uniform and inorganic-rich LiF/Li2 O/Li3 N layer on the bottom of PVDF/LiF with good mechanical strength, resulting in the dendrite free anode in cell cycling. The assembled Li//LiFePO4 and Li//NMC811 batteries show the capacity retention rate of 80.9% after 800 cycles and 82.3% after 500 cycles, respectively, much higher than those of references.

Accelerating S↔Li2 S Reactions in Li-S Batteries through Activation of S/Li2 S with a Bifunctional Semiquinone Catalyst.

The reaction rate bottleneck during interconversion between insulating S8 (S) and Li2 S fundamentally leads to incomplete conversion and restricted lifespan of Li-S battery, especially under high S loading and lean electrolyte conditions. Herein, we demonstrate a new catalytic chemistry: soluble semiquinone, 2-tertbutyl-semianthraquinone lithium (Li+ TBAQ⋅- ), as both e- /Li+ donor and acceptor for simultaneous S reduction and Li2 S oxidation. The efficient activation of S and Li2 S by Li+ TBAQ⋅- in the initial discharging/charging state maximizes the amount of soluble lithium polysulfide, thereby substantially improve the rate of solid-liquid-solid reaction by promoting long-range electron transfer. With in situ Raman spectra and theoretical calculations, we reveal that the activation of S/Li2 S is the rate-limiting step for effective S utilization under high S loading and low E/S ratio. Beyond that, the S activation ratio is firstly proposed as an accurate indicator to quantitatively evaluate the reaction rate. As a result, the Li-S batteries with Li+ TBAQ⋅- deliver superior cycling performance and over 5 times higher S utilization ratio at high S loading of 7.0 mg cm-2 and a current rate of 1 C compared to those without Li+ TBAQ⋅- . We hope this study contributes to the fundamental understanding of S redox chemical and inspires the design of efficient catalysis for advanced Li-S batteries.

Ordered and Fast Ion Transport of Quasi-solid-state Electrolyte with Regulated Coordination Strength for Lithium Metal Batteries.

Polymer based quasi-solid-state electrolyte (QSE) has attracted great attention due to its assurance for high safety of rechargeable batteries including lithium metal batteries (LMB). However, it faces the issue of low ionic conductivity of electrolyte and solid-electrolyte-interface (SEI) layer between QSE and lithium anode. Herein, we firstly demonstrate that the ordered and fast transport of lithium ion (Li+ ) can be realized in QSE. Due to the higher coordination strength of Li+ on tertiary amine (-NR3 ) group of polymer network than that on carbonyl (-C=O) group of ester solvent, Li+ can diffuse orderly and quickly on -NR3 of polymer, significantly increasing the ionic conductivity of QSE to 3.69 mS cm-1 . Moreover, -NR3 of polymer can induce in situ and uniform generation of Li3 N and LiNx Oy in SEI. As a result, the Li||NCM811 batteries (50 µm Li foil) with this QSE show an excellent stability of 220 cycles at ≈1.5 mA cm-2 , 5 times to those with conventional QSE. LMBs with LiFePO4 can stably run for ≈8300 h. This work demonstrates an attractive concept for improving ionic conductivity of QSE, and also provides an important step for developing advanced LMB with high cycle stability and safety.

Proteins That Read DNA Methylation.

Covalent modification of DNA via deposition of a methyl group at the 5' position on cytosine residues alters the chemical groups available for interaction in the major groove of DNA. This modification, thereby, alters the affinity and specificity of DNA-binding proteins; some of them favor interaction with methylated DNA, and others disfavor it. Molecular recognition of cytosine methylation by proteins often initiates sequential regulatory events that impact gene expression and chromatin structure. The known methyl-DNA-binding proteins have unique domains responsible for DNA methylation recognition: (1) the methyl-CpG-binding domain (MBD), (2) the SET- and RING finger-associated domain (SRA), and (3) some of TF families, such as the C2H2 zinc finger domain, basic helix-loop-helix (bHLH), basic leucine-zipper (bZIP), and homeodomain proteins. Structural analyses have revealed that each domain has a characteristic methylated DNA-binding pattern, and the difference in the recognition mechanisms renders the DNA methylation mark able to transmit complicated biological information. Recent genetic and genomic studies have revealed novel functions of methyl-DNA-binding proteins. These emerging data have also provided glimpses into how methyl-DNA-binding proteins possess unique features and, presumably, functions. In this chapter, we summarize structural and biochemical analyses elucidating the mechanisms for recognition of DNA methylation and correlate this information with emerging genomic and functional data.

A higher-order configuration of the heterodimeric DOT1L-AF10 coiled-coil domains potentiates their leukemogenenic activity.

Chromosomal translocations of MLL1 (Mixed Lineage Leukemia 1) yield oncogenic chimeric proteins containing the N-terminal portion of MLL1 fused with distinct partners. The MLL1-AF10 fusion causes leukemia through recruiting the H3K79 histone methyltransferase DOT1L via AF10's octapeptide and leucine zipper (OM-LZ) motifs. Yet, the precise interaction sites in DOT1L, detailed interaction modes between AF10 and DOT1L, and the functional configuration of MLL1-AF10 in leukeomogenesis remain unknown. Through a combined approach of structural and functional analyses, we found that the LZ domain of AF10 interacts with the coiled-coil domains of DOT1L through a conserved binding mode and discovered that the C-terminal end of the LZ domain and the OM domain of AF10 mediate the formation of a DOT1L-AF10 octamer via tetramerization of the binary complex. We reveal that the oligomerization ability of the DOT1L-AF10 complex is essential for MLL1-AF10's leukemogenic function. These findings provide insights into the molecular basis of pathogenesis by MLL1 rearrangements.

Biphasic Electrolyte Inhibiting the Shuttle Effect of Redox Molecules in Lithium-Metal Batteries.

Redox molecules (RMs) as electron carriers have been widely used in electrochemical energy-storage devices (ESDs), such as lithium redox flow batteries and lithium-O2 batteries. Unfortunately, migration of RMs to the lithium (Li) anode leads to side reactions, resulting in reduced coulombic efficiency and early cell death. Our proof-of-concept study utilizes a biphasic organic electrolyte to resolve this issue, in which nonafluoro-1,1,2,2-tetrahydrohexyl-trimethoxysilane (NFTOS) and ether (or sulfone) with lithium bis(trifluoromethane)sulfonimide (LiTFSI) can be separated to form the immiscible anolyte and catholyte. RMs are extracted to the catholyte due to the enormous solubility coefficients in the biphasic electrolytes with high and low polarity, resulting in inhibition of the shuttle effect. When coupled with a lithium anode, the Li-Li symmetric, Li redox flow and Li-O2 batteries can achieve considerably prolonged cycle life with biphasic electrolytes. This concept provides a promising strategy to suppress the shuttle effect of RMs in ESDs.

A Liquid/Liquid Electrolyte Interface that Inhibits Corrosion and Dendrite Growth of Lithium in Lithium-Metal Batteries.

A proof-of-concept study on a liquid/liquid (L/L) two-phase electrolyte interface is reported by using the polarity difference of solvent for the protection of Li-metal anode with long-term operation over 2000 h. The L/L electrolyte interface constructed by non-polar fluorosilicane (PFTOS) and conventionally polar dimethyl sulfoxide solvents can block direct contact between conventional electrolyte and Li anode, and consequently their side reactions can be significantly eliminated. Moreover, the homogeneous Li-ion flow and Li-mass deposition can be realized by the formation of a thin and uniform solid-electrolyte interphase (SEI) composed of LiF, Lix C, Lix SiOy between PFTOS and Li anode, as well as the super-wettability state of PFTOS to Li anode, resulting in the suppression of Li dendrite formation. The cycling stability in a lithium-oxygen battery as a model is improved 4 times with the L/L electrolyte interface.

Chemical tools for the Gid4 subunit of the human E3 ligase C-terminal to LisH (CTLH) degradation complex.

We have developed a novel chemical handle (PFI-E3H1) and a chemical probe (PFI-7) as ligands for the Gid4 subunit of the human E3 ligase CTLH degradation complex. Through an efficient initial hit-ID campaign, structure-based drug design (SBDD) and leveraging the sizeable Pfizer compound library, we identified a 500 nM ligand for this E3 ligase through file screening alone. Further exploration identified a vector that is tolerant to addition of a linker for future chimeric molecule design. The chemotype was subsequently optimized to sub-100 nM Gid4 binding affinity for a chemical probe. These novel tools, alongside the suitable negative control also identified, should enable the interrogation of this complex human E3 ligase macromolecular assembly.

A unique binding pocket induced by a noncanonical SAH mimic to develop potent and selective PRMT inhibitors.

Protein arginine methyltransferases (PRMTs) are attractive targets for developing therapeutic agents, but selective PRMT inhibitors targeting the cofactor SAM binding site are limited. Herein, we report the discovery of a noncanonical but less polar SAH surrogate YD1113 by replacing the benzyl guanidine of a pan-PRMT inhibitor with a benzyl urea, potently and selectively inhibiting PRMT3/4/5. Importantly, crystal structures reveal that the benzyl urea moiety of YD1113 induces a unique and novel hydrophobic binding pocket in PRMT3/4, providing a structural basis for the selectivity. In addition, YD1113 can be modified by introducing a substrate mimic to form a "T-shaped" bisubstrate analogue YD1290 to engage both the SAM and substrate binding pockets, exhibiting potent and selective inhibition to type I PRMTs (IC50 < 5 nmol/L). In summary, we demonstrated the promise of YD1113 as a general SAH mimic to build potent and selective PRMT inhibitors.

Inhibition of Discharge Side Reactions by Promoting Solution-Mediated Oxygen Reduction Reaction with Stable Quinone in Li-O2 Batteries.

Aprotic lithium-oxygen (Li-O2) batteries with an ultrahigh theoretical energy density have great potential in rechargeable power supply, while their application still faces several challenges, especially poor cycle stability. To solve the problems, one of the effective strategies is to inhibit the generation of the LiO2 intermediate produced via a surface-mediated oxygen reduction reaction (ORR) pathway, which is an important species inducing byproduct generation and low cell cyclic stability. Herein, a series of quinones and solid materials serve as the solution-mediated and surface-mediated ORR catalysts, and it was found that the generation of LiO2 and byproducts from solid catalysts was inhibited by quinones. Among the studied quinones, benzo[1,2-b:4,5-b']dithiophene-4,8-dione, a quinone molecule with the advantage of a highly symmetrical planar and conjugated structure and without α-H, exhibits high redox potential, diffusion coefficient, and electrochemical stability, and consequently the best ORR activities and the capability to inhibit byproduct generation. It indicated that the increase of the solution-mediated ORR pathway plays an important role in restraining the discharging side reaction, substantially improving cell cycle stability and capacity. This study provides the theoretical and experimental basis for better understanding the ORR process of Li-O2 batteries.

Structural Basis for EPC1-Mediated Recruitment of MBTD1 into the NuA4/TIP60 Acetyltransferase Complex.

MBTD1, a H4K20me reader, has recently been identified as a component of the NuA4/TIP60 acetyltransferase complex, regulating gene expression and DNA repair. NuA4/TIP60 inhibits 53BP1 binding to chromatin through recognition of the H4K20me mark by MBTD1 and acetylation of H2AK15, blocking the ubiquitination mark required for 53BP1 localization at DNA breaks. The NuA4/TIP60 non-catalytic subunit EPC1 enlists MBTD1 into the complex, but the detailed molecular mechanism remains incompletely explored. Here, we present the crystal structure of the MBTD1-EPC1 complex, revealing a hydrophobic C-terminal fragment of EPC1 engaging the MBT repeats of MBTD1 in a site distinct from the H4K20me binding site. Different cellular assays validate the physiological significance of the key residues involved in the MBTD1-EPC1 interaction. Our study provides a structural framework for understanding the mechanism by which MBTD1 recruits the NuA4/TIP60 acetyltransferase complex to influence transcription and DNA repair pathway choice.

Promising Dual-Doped Graphene Aerogel/SnS2 Nanocrystal Building High Performance Sodium Ion Batteries.

We report the effort in designing layered SnS2 nanocrystals decorated on nitrogen and sulfur dual-doped graphene aerogels (SnS2@N,S-GA) as anode material of SIBs. The optimized mass loading of SnS2 along with the addition of nitrogen and sulfur on the surface of GAs results in enhanced electrochemical performance of SnS2@N,S-GA composite. In particular, the introduction of nitrogen and sulfur heteroatoms could provide more active sites and good accessibility for Na ions. Moreover, the incorporation of the stable SnS2 crystal structure within the anode results in the superior discharge capacity of 527 mAh g-1 under a current density of 20 mA g-1 upon 50 cycles. It maintains 340 mAh g-1 even the current density is increased to 800 mA g-1. Aiming to further systematically study mechanism of composite with improved SIB performance, we construct the corresponding models based on experimental data and conduct first-principles calculations. The calculated results indicate the sulfur atoms doped in GAs show a strong bridging effect with the SnS2 nanocrystals, contributing to build robust architecture for electrode. Simultaneously, heteroatom dual doping of GAs shows the imperative function for improved electrical conductivity. Herein, first-principles calculations present a theoretical explanation for outstanding cycling properties of SnS2@N,S-GA composite.