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1.
Chemistry ; : e202402199, 2024 Aug 08.
Article in English | MEDLINE | ID: mdl-39117600

ABSTRACT

Isoindigo, an electron-withdrawing building block for polymeric field-effect transistors, has long been considered to be non-fluorescent. Moreover, using electron-deficient heterocycle to replace the phenyl ring in the isoindigo core for better electron transport behaviour is synthetically challenging. Here we report the syntheses of a series of tetraazaisoindigos, including pyrazinoisoindigo (PyrII), pyrimidoisoindigo (PymII) and their hybrid (PyrPymII), and the investigation on their photophysical and electric properties. Proper flanking groups need to be chosen to stabilize these highly electron-deficient bislactams. Both PyrII and PymII derivatives show lower LUMO energy levels than that of naphthalene bisimide (NDI). Interestingly, PyrII is instinctively unstable and can be easily reduced, while both PymII derivatives are stable. More surprisingly, PymII derivatives are highly fluorescent and their photoluminescence quantum yields are around 40%, 133 times higher than that of reported isoindigo derivatives. UV-vis spectroscopic results and theoretical calculations show that strong intramolecular hydrogen-bond exists in PymII, which prohibits it from non-radiative decay and accounts for its fluorescent behaviour.  PymII deriviatives are n-type semiconductors, while Ph-PyrII and the hybrid show balanced ambipolar charge transport behaviour, all among the best isoindigo derivatives. Our study not only discloses the structure-property relationship of tetraazaisoindigos, but also provides electron-deficient monomers for conjugated polymers.

2.
Cell ; 187(9): 2194-2208.e22, 2024 Apr 25.
Article in English | MEDLINE | ID: mdl-38552625

ABSTRACT

Effective treatments for complex central nervous system (CNS) disorders require drugs with polypharmacology and multifunctionality, yet designing such drugs remains a challenge. Here, we present a flexible scaffold-based cheminformatics approach (FSCA) for the rational design of polypharmacological drugs. FSCA involves fitting a flexible scaffold to different receptors using different binding poses, as exemplified by IHCH-7179, which adopted a "bending-down" binding pose at 5-HT2AR to act as an antagonist and a "stretching-up" binding pose at 5-HT1AR to function as an agonist. IHCH-7179 demonstrated promising results in alleviating cognitive deficits and psychoactive symptoms in mice by blocking 5-HT2AR for psychoactive symptoms and activating 5-HT1AR to alleviate cognitive deficits. By analyzing aminergic receptor structures, we identified two featured motifs, the "agonist filter" and "conformation shaper," which determine ligand binding pose and predict activity at aminergic receptors. With these motifs, FSCA can be applied to the design of polypharmacological ligands at other receptors.


Subject(s)
Cheminformatics , Drug Design , Polypharmacology , Animals , Mice , Humans , Cheminformatics/methods , Ligands , Receptor, Serotonin, 5-HT2A/metabolism , Receptor, Serotonin, 5-HT2A/chemistry , Receptor, Serotonin, 5-HT1A/metabolism , Receptor, Serotonin, 5-HT1A/chemistry , Male , Binding Sites
3.
Nat Commun ; 14(1): 8067, 2023 Dec 06.
Article in English | MEDLINE | ID: mdl-38057319

ABSTRACT

The lipid prostaglandin E2 (PGE2) mediates inflammatory pain by activating G protein-coupled receptors, including the prostaglandin E2 receptor 4 (EP4R). Nonsteroidal anti-inflammatory drugs (NSAIDs) reduce nociception by inhibiting prostaglandin synthesis, however, the disruption of upstream prostanoid biosynthesis can lead to pleiotropic effects including gastrointestinal bleeding and cardiac complications. In contrast, by acting downstream, EP4R antagonists may act specifically as anti-inflammatory agents and, to date, no selective EP4R antagonists have been approved for human use. In this work, seeking to diversify EP4R antagonist scaffolds, we computationally dock over 400 million compounds against an EP4R crystal structure and experimentally validate 71 highly ranked, de novo synthesized molecules. Further, we show how structure-based optimization of initial docking hits identifies a potent and selective antagonist with 16 nanomolar potency. Finally, we demonstrate favorable pharmacokinetics for the discovered compound as well as anti-allodynic and anti-inflammatory activity in several preclinical pain models in mice.


Subject(s)
Dinoprostone , Receptors, Prostaglandin , Humans , Mice , Animals , Phagocytosis , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/therapeutic use , Pain/drug therapy , Anti-Inflammatory Agents, Non-Steroidal/pharmacology
4.
Medicine (Baltimore) ; 102(39): e34856, 2023 Sep 29.
Article in English | MEDLINE | ID: mdl-37773800

ABSTRACT

BACKGROUND: High-risk proliferative diabetic retinopathy (HR-PDR) is the advanced stage of diabetic retinopathy progression with poor prior treatment efficacy and high rates of blindness. This meta-analysis aims to compare the efficacy and safety of pan retinal photocoagulation (PRP) combined with intravitreal anti-vascular endothelial growth factor (aVEGF) (PRP + aVEGF) versus PRP monotherapy in HR-PDR patients. METHODS: A thorough search was performed through PubMed, Web of Science, EMBASE, and the Cochran Library from inception to December 18, 2022. Outcome measures included change in central macular thickness, best-corrected visual acuity, fluorescein angiography, incidence of undergoing vitrectomy, and adverse events during the follow-up period. RESULTS: Eight studies (6 randomized controlled trials and 2 retrospective studies) with 375 eyes were included in this meta-analysis. There were no obvious differences in the changes of best-corrected visual acuity and fluorescein angiography between the PRP + aVEGF and PRP monotherapy groups. However, PRP + aVEGF group had a significant reduction in the change of central macula thickness (standard mean deviations = -1.44, 95%CI = -2.55 to -0.32, P = .01) and the rate of undergoing vitrectomy (odds ratio = 0.20, 95%CI = 0.05-0.83, P = .01). Additionally, the risks of vitreous hemorrhage and other complications were not significantly different between the 2 groups. CONCLUSION SUBSECTIONS: Our meta-analysis indicated that PRP + aVEGF might have potential benefits in the treatment of HR-PDR patients. However, given several limitations of this study, more research is needed to confirm our findings.


Subject(s)
Diabetes Mellitus , Diabetic Retinopathy , Humans , Angiogenesis Inhibitors/adverse effects , Diabetes Mellitus/drug therapy , Diabetic Retinopathy/drug therapy , Intravitreal Injections , Laser Coagulation , Retrospective Studies , Vascular Endothelial Growth Factors/antagonists & inhibitors
5.
Protein Sci ; 32(8): e4712, 2023 08.
Article in English | MEDLINE | ID: mdl-37354015

ABSTRACT

Antiviral therapeutics to treat SARS-CoV-2 are needed to diminish the morbidity of the ongoing COVID-19 pandemic. A well-precedented drug target is the main viral protease (MPro ), which is targeted by an approved drug and by several investigational drugs. Emerging viral resistance has made new inhibitor chemotypes more pressing. Adopting a structure-based approach, we docked 1.2 billion non-covalent lead-like molecules and a new library of 6.5 million electrophiles against the enzyme structure. From these, 29 non-covalent and 11 covalent inhibitors were identified in 37 series, the most potent having an IC50 of 29 and 20 µM, respectively. Several series were optimized, resulting in low micromolar inhibitors. Subsequent crystallography confirmed the docking predicted binding modes and may template further optimization. While the new chemotypes may aid further optimization of MPro inhibitors for SARS-CoV-2, the modest success rate also reveals weaknesses in our approach for challenging targets like MPro versus other targets where it has been more successful, and versus other structure-based techniques against MPro itself.


Subject(s)
COVID-19 , Humans , SARS-CoV-2/metabolism , Pandemics , Protease Inhibitors/pharmacology , Protease Inhibitors/chemistry , Molecular Docking Simulation , Viral Nonstructural Proteins/chemistry , Antiviral Agents/pharmacology , Antiviral Agents/chemistry
6.
J Med Chem ; 66(12): 7785-7803, 2023 06 22.
Article in English | MEDLINE | ID: mdl-37294077

ABSTRACT

An under-explored target for SARS-CoV-2 is the S-adenosyl methionine (SAM)-dependent methyltransferase Nsp14, which methylates the N7-guanosine of viral RNA at the 5'-end, allowing the virus to evade host immune response. We sought new Nsp14 inhibitors with three large library docking strategies. First, up to 1.1 billion lead-like molecules were docked against the enzyme's SAM site, leading to three inhibitors with IC50 values from 6 to 50 µM. Second, docking a library of 16 million fragments revealed 9 new inhibitors with IC50 values from 12 to 341 µM. Third, docking a library of 25 million electrophiles to covalently modify Cys387 revealed 7 inhibitors with IC50 values from 3.5 to 39 µM. Overall, 32 inhibitors encompassing 11 chemotypes had IC50 values < 50 µM and 5 inhibitors in 4 chemotypes had IC50 values < 10 µM. These molecules are among the first non-SAM-like inhibitors of Nsp14, providing starting points for future optimization.


Subject(s)
COVID-19 , Methyltransferases , Humans , SARS-CoV-2/genetics , Viral Nonstructural Proteins/genetics , RNA, Viral/genetics , Exoribonucleases
7.
J Mater Chem B ; 10(44): 9295-9304, 2022 11 16.
Article in English | MEDLINE | ID: mdl-36345846

ABSTRACT

Block copolymers with different topologies (linear, loop, 3-armed and 4-armed polymers) containing poly(N-vinylpyrrrolidone) (PVP) antifouling blocks and terminal poly(dopamine-acrylamide) (PDAA) anchoring blocks were synthesized. These polymers can form a robust antifouling nanolayer on various surfaces. The morphologies of the polymer-modified surfaces are strongly dependent on the topologies of the polymers: with the increase of arm numbers, the morphology evolves from the smooth surface to the nanoscale coarse surface. As a result, the hydrophilicity of the coatings increases with the increase of degree of nanoscale roughness, and the 4-armed block copolymer forms a superhydrophilic surface with a water contact angle (WCA) as low as 8.7°. Accordingly, the linear diblock copolymer exhibits the worst antifouling efficiency, while the 4-armed polymer exhibits the best antifouling efficiency. This is the first example systematically showing that the antifouling efficacy could be adjusted simply by the topology of the coatings. Cell viability studies revealed that all of the copolymers exhibit excellent cytocompatibility. These biocompatible polymers with narrowly distributed molecular weight might find niches for antifouling applications in various areas such as anti-protein absorption, anti-bacterial and anti-marine fouling.


Subject(s)
Biofouling , Biofouling/prevention & control , Polymers/pharmacology , Hydrophobic and Hydrophilic Interactions , Water
8.
Nat Chem Biol ; 18(9): 934-941, 2022 09.
Article in English | MEDLINE | ID: mdl-35590003

ABSTRACT

The expansion of the target landscape of covalent inhibitors requires the engagement of nucleophiles beyond cysteine. Although the conserved catalytic lysine in protein kinases is an attractive candidate for a covalent approach, selectivity remains an obvious challenge. Moreover, few covalent inhibitors have been shown to engage the kinase catalytic lysine in animals. We hypothesized that reversible, lysine-targeted inhibitors could provide sustained kinase engagement in vivo, with selectivity driven in part by differences in residence time. By strategically linking benzaldehydes to a promiscuous kinase binding scaffold, we developed chemoproteomic probes that reversibly and covalently engage >200 protein kinases in cells and mice. Probe-kinase residence time was dramatically enhanced by a hydroxyl group ortho to the aldehyde. Remarkably, only a few kinases, including Aurora A, showed sustained, quasi-irreversible occupancy in vivo, the structural basis for which was revealed by X-ray crystallography. We anticipate broad application of salicylaldehyde-based probes to proteins that lack a druggable cysteine.


Subject(s)
Lysine , Protein Kinase Inhibitors , Animals , Cysteine/metabolism , Lysine/metabolism , Mice , Protein Binding , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Protein Kinases/metabolism
9.
Appl Environ Microbiol ; 87(11)2021 05 11.
Article in English | MEDLINE | ID: mdl-33712426

ABSTRACT

Selective oxidation of C-H bonds in alkylphenols holds great significance for not only structural derivatization in pharma- and biomanufacturing but also biological degradation of these toxic chemicals in environmental protection. A unique chemomimetic biocatalytic system using enzymes from a p-cresol biodegradation pathway has recently been developed. As the central biocatalyst, the cytochrome P450 monooxygenase CreJ oxidizes diverse p- and m-alkylphenol phosphates with perfect stereoselectivity at different efficiencies. However, the mechanism of regio- and stereoselectivity of this chemomimetic biocatalytic system remained unclear. Here, using p- and m-ethylphenol substrates, we elucidate the CreJ-catalyzed key steps for selective oxidations. The crystal structure of CreJ in complex with m-ethylphenol phosphate was solved and compared with its complex structure with p-ethylphenol phosphate isomer. The results indicate that the conformational changes of substrate-binding residues are slight, while the substrate promiscuity is achieved mainly by the available space in the catalytic cavity. Moreover, the catalytic preferences of regio- and stereoselective hydroxylation for the two ethylphenol substrates is explored by molecular dynamics simulations. The ethyl groups in the complexes display different flexibilities, and the distances of the active oxygen to H pro-S and H pro-R of methylene agree with the experimental stereoselectivity. The regioselectivity can be explained by the distances and bond dissociation energy. These results provide not only the mechanistic insights into CreJ regio- and stereoselectivity but also the structural basis for further P450 enzyme design and engineering.IMPORTANCE The key cytochrome P450 monooxygenase CreJ showed excellent regio- and stereoselectivity in the oxidation of various alkylphenol substrates. C-H bond functionalization of these toxic alkylphenols holds great significance for both biological degradation of these environmental chemicals and production of value-added structural derivatives in pharmaceutical and biochemical industries. Our results, combined with in vitro enzymatic assays, crystal structure determination of enzyme-substrate complex, and molecular dynamics simulations, provide not only significant mechanism elucidation of the regio- and stereoselective catalyzation mediated by CreJ but also the promising directions for future engineering efforts of this enzyme toward more useful products. It also has great extendable potential to couple this multifunctional P450 enzyme with other biocatalysts (e.g., hydroxyl-based glycosylase) to access more alkylphenol-derived high-value chemicals through environment-friendly biocatalysis and biotransformation.


Subject(s)
Bacterial Proteins/metabolism , Corynebacterium glutamicum/metabolism , Phenols/metabolism , Oxidation-Reduction , Phosphorylation
10.
ACS Appl Bio Mater ; 4(2): 1360-1368, 2021 02 15.
Article in English | MEDLINE | ID: mdl-35014487

ABSTRACT

The development of functional materials based on renewable resources is of great significance in today's resource shortage. Here, we present an effective way to synthesize a mussel-inspired adhesive from acrylated epoxidized soybean oil (AESO), a renewable and commercially available small molecular material with a molecular weight around 1200 Da, by a one-step esterification reaction with the affordable 3,4-dihydroxybenzoic acid (DHA). By taking advantages of both the double bond and the catechol moiety presented in this small molecular adhesive, a short curing time was achieved with UV irradiation. An average bonding strength around 1.4 MPa at a curing time of only around 10 min on a glass substrate was observed, which reached 3.1 MPa (average 2.8 MPa) at a curing time of 2 h under ambient conditions. The curing time is much shorter, and the bonding strength is obviously stronger than the conditions where conventional oxidation agents such as IO4- or oxidation/coordination agents such as Fe3+ are used as the curing agent. Furthermore, the AESO-g-DHA can be used as an underwater adhesive, and an appreciable bonding strength up to 0.64 MPa was observed, which is superior than most of currently known commercialized glues. Given that the adhesive could be synthesized from low-cost renewable resources in one step, it might be a potential candidate for large-scale practical application.


Subject(s)
Adhesives/chemistry , Biomimetic Materials/chemistry , Bivalvia , Plant Oils/chemistry , Animals , Iron , Materials Testing , Molecular Structure , Periodic Acid , Ultraviolet Rays
11.
Ann Palliat Med ; 9(3): 1013-1019, 2020 May.
Article in English | MEDLINE | ID: mdl-32434359

ABSTRACT

BACKGROUND: During the remove of oil from the silicone oil-filled eye after vitrectomy, perfusion fluid is often mistakenly aspirated when mechanical force is used to remove the oil. This leads to a sudden sharp drop in intraocular pressure and collapse of the eyeball, which may cause complications. The aspiration of perfusion fluid can be detected when the oil is removed manually, and the force of the hand and location of the aspiration can be adjusted to remove the silicone oil instead. In this study, we assessed the efficacy and safety of a manual 23-gauge (23G) silicone oil remove method and confirmed that this is a feasible, highly efficient, safe, simple and economical way to remove oil. METHODS: We recruited 130 patients (130 affected eyes) 3-6 months after they had undergone vitrectomy and light silicone oil tamponade at our hospital. The patients/eyes were randomly divided into two groups (manual or vitrectomy system), with 65 eyes in each group. All eyes in both groups underwent 23G oil remove by the same physician. The following aspects of the two groups were compared: 1. Oil remove duration; 2. Average intraocular pressure at 1 day, 1 week and 1 month after the procedure; and 3. Postoperative complications, such as retinal redetachment, silicone oil residue, massive suprachoroidal hemorrhage and choroid detachment. RESULTS: The average oil remove durations of the manual group and the vitrectomy system group were 5.92±1.34 and 8.87±1.68 min, respectively (P<0.05); the duration for the manual group was significantly shorter than that for the vitrectomy system group (t=11.07, P=0). The average intraocular pressures at 1 day, 1 week and 1 month after operation of the manual group were 10.2±2.7, 15.2±3.5 and 17.2±3.1 mmHg, respectively, and those of the vitrectomy system group were 9.8±2.4, 15.5±3.1 and 16.8±3.4 mmHg, respectively; the differences between the two groups were not statistically significant at any time point (t=0.892, P=0.374 at 1 day; t=0.517, P=0.606 at 1 week; and t=0.701, P=0.485 at 1 month). The difference in the incidence of postoperative complications, including retinal redetachment, silicone oil residue, massive suprachoroidal hemorrhage and choroid detachment, between the two groups was statistically significant (χ 2 =4.2787, P=0.0386). None of the affected eyes were complicated with transient intraocular hypotension, vitreous hemorrhage or endophthalmitis. CONCLUSIONS: The manual 23G silicone oil remove method is highly efficient, safe, simple and economical and can be used conveniently and clinically by the majority of medical institutions.


Subject(s)
Retinal Detachment , Silicone Oils , Vitrectomy , Aged , Humans , Intraocular Pressure , Postoperative Complications/prevention & control , Retinal Detachment/surgery
12.
J Am Chem Soc ; 142(11): 4960-4964, 2020 03 18.
Article in English | MEDLINE | ID: mdl-32105459

ABSTRACT

Eukaryotic translation initiation factor 4E (eIF4E) binds the m7GTP cap structure at the 5'-end of mRNAs, stimulating the translation of proteins implicated in cancer cell growth and metastasis. eIF4E is a notoriously challenging target, and most of the reported inhibitors are negatively charged guanine analogues with negligible cell permeability. To overcome these challenges, we envisioned a covalent targeting strategy. As there are no cysteines near the eIF4E cap binding site, we developed a covalent docking approach focused on lysine. Taking advantage of a "make-on-demand" virtual library, we used covalent docking to identify arylsulfonyl fluorides that target a noncatalytic lysine (Lys162) in eIF4E. Guided by cocrystal structures, we elaborated arylsulfonyl fluoride 2 to 12, which to our knowledge is the first covalent eIF4E inhibitor with cellular activity. In addition to providing a new tool for acutely inactivating eIF4E in cells, our computational approach may offer a general strategy for developing selective lysine-targeted covalent ligands.


Subject(s)
Eukaryotic Initiation Factor-4E/antagonists & inhibitors , Lysine/chemistry , Sulfonamides/pharmacology , Binding Sites , Drug Discovery , Eukaryotic Initiation Factor-4E/chemistry , Eukaryotic Initiation Factor-4E/metabolism , HEK293 Cells , Humans , Molecular Docking Simulation , Protein Binding , Sulfonamides/metabolism
13.
J Am Chem Soc ; 142(7): 3392-3400, 2020 02 19.
Article in English | MEDLINE | ID: mdl-32009391

ABSTRACT

Targeted covalent modification of surface-exposed lysines is challenging due to their low intrinsic reactivity and high prevalence throughout the proteome. Strategies for optimizing the rate of covalent bond formation by a reversibly bound inhibitor (kinact) typically involve increasing the reactivity of the electrophile, which increases the risk of off-target modification. Here, we employ an alternative approach for increasing kinact of a lysine-targeted covalent Hsp90 inhibitor, independent of the reversible binding affinity (Ki) or the intrinsic electrophilicity. Starting with a noncovalent ligand, we appended a chiral, conformationally constrained linker, which orients an arylsulfonyl fluoride to react rapidly and enantioselectively with Lys58 on the surface of Hsp90. Biochemical experiments and high-resolution crystal structures of covalent and noncovalent ligand/Hsp90 complexes provide mechanistic insights into the role of ligand conformation in the observed enantioselectivity. Finally, we demonstrate selective covalent targeting of cellular Hsp90, which results in a prolonged heat shock response despite concomitant degradation of the covalent ligand/Hsp90 complex. Our work highlights the potential of engineering ligand conformational constraints to dramatically accelerate covalent modification of a distal, poorly nucleophilic lysine on the surface of a protein target.


Subject(s)
HSP90 Heat-Shock Proteins/antagonists & inhibitors , Lysine/chemistry , Sulfones/pharmacology , Cell Line, Tumor , HSP90 Heat-Shock Proteins/chemistry , Humans , Ligands , Stereoisomerism , Sulfones/chemical synthesis , Sulfones/chemistry
14.
J Chem Inf Model ; 59(10): 4116-4119, 2019 10 28.
Article in English | MEDLINE | ID: mdl-31609618

ABSTRACT

A flexible-receptor docking protocol was designed for treating binding-site side-chain flexibility by integrating essential aspects of "Conformational Selection" and "Induced Fit" in a hierarchical fashion. Assessed in a diverse set of pharmaceutically relevant targets, this protocol showed improved performance in reproducing binding poses and ligand enrichment studies compared to rigid-receptor docking. Moreover, it has also exhibited encouraging efficiency in prospective ligand discovery for Pim-1 kinase, which led to novel Pim-1 inhibitors with single-digit nanomolar potencies.


Subject(s)
Drug Discovery , Molecular Dynamics Simulation , Proto-Oncogene Proteins c-pim-1/antagonists & inhibitors , Catalytic Domain , Models, Molecular , Protein Conformation
15.
Front Chem ; 7: 467, 2019.
Article in English | MEDLINE | ID: mdl-31316975

ABSTRACT

The assembly of a peptide-tetrathiophene-peptide (PTP) conjugate has been investigated in mixed solvents, which has different polarities by changing the solvent proportions. It was found that PTP can form fibers in THF/hexane solutions with 40-80%v of hexane. The fibers were stable and did not change on time. On the other hand, PTP formed ordered structures in a mixed solution with the water content from 40 to 60%v. For the as-prepared solutions, two nanostructures vesicles and parallelogram sheets were obtained. The parallelogram sheets could transform into vesicles on time. The fibers showed supramolecular chirality, however, there was no Cotton effect for vesicles and parallelogram sheets. UV-vis, FL, XRD, FT-IR, and CD spectra together with SEM, AFM, TEM were used to characterize the nanostructures and properties of the assemblies. Molecular packing mechanism was proposed based on the experimental data.

16.
Proc Natl Acad Sci U S A ; 116(27): 13305-13310, 2019 07 02.
Article in English | MEDLINE | ID: mdl-31209052

ABSTRACT

Mycophenolic acid (MPA) from filamentous fungi is the first natural product antibiotic to be isolated and crystallized, and a first-line immunosuppressive drug for organ transplantations and autoimmune diseases. However, some key biosynthetic mechanisms of such an old and important molecule have remained unclear. Here, we elucidate the MPA biosynthetic pathway that features both compartmentalized enzymatic steps and unique cooperation between biosynthetic and ß-oxidation catabolism machineries based on targeted gene inactivation, feeding experiments in heterologous expression hosts, enzyme functional characterization and kinetic analysis, and microscopic observation of protein subcellular localization. Besides identification of the oxygenase MpaB' as the long-sought key enzyme responsible for the oxidative cleavage of the farnesyl side chain, we reveal the intriguing pattern of compartmentalization for the MPA biosynthetic enzymes, including the cytosolic polyketide synthase MpaC' and O-methyltransferase MpaG', the Golgi apparatus-associated prenyltransferase MpaA', the endoplasmic reticulum-bound oxygenase MpaB' and P450-hydrolase fusion enzyme MpaDE', and the peroxisomal acyl-coenzyme A (CoA) hydrolase MpaH'. The whole pathway is elegantly comediated by these compartmentalized enzymes, together with the peroxisomal ß-oxidation machinery. Beyond characterizing the remaining outstanding steps of the MPA biosynthetic steps, our study highlights the importance of considering subcellular contexts and the broader cellular metabolism in natural product biosynthesis.


Subject(s)
Mycophenolic Acid/metabolism , Aspergillus oryzae/metabolism , Endoplasmic Reticulum/metabolism , Golgi Apparatus/metabolism , Metabolic Networks and Pathways , Oxidation-Reduction , Penicillium/metabolism , Peroxisomes/metabolism , Subcellular Fractions/enzymology , Subcellular Fractions/metabolism
17.
RSC Adv ; 9(22): 12310-12318, 2019 Apr 17.
Article in English | MEDLINE | ID: mdl-35515838

ABSTRACT

Lactam-containing acceptors, which could provide two potential alkylation positions (N-alkylation and O-alkylation), are important building blocks for polymeric donors in high performance polymer solar cells (PSCs). However, the influence of alkylation positions on the PSC performance has seldom been studied. Herein, we investigated the influence of O-alkylation and N-alkylation on a novel bislactam acceptor, namely dibenzonaphthyridinedione (DBND), on the physical properties of the corresponding polymers and hence their PSC performance. Besides O-alkylated and N-alkylated DBND, half-N-alkylated-half-O-alkylated DBND (N,O-DBND) was also prepared and copolymerized with stannyl bithiophene (2T). It was found that by varying the alkylation positions, the optical, crystalline and aggregation properties of the corresponding polymers were greatly altered. In comparison with P(N-DBND-2T) and P(O-DBND-2T), P(N,O-DBND-2T) shows both better solubility and shorter π-π stacking distance. By blending with PC71BM, P(N,O-DBND-2T) forms better nano-fibrillar phase separation so that less charge recombination is observed, thus leading to a much better power conversion efficiency (PCE) around 5%, which is the highest value of the conjugated system based on N,O-alkylated acceptors. The results show that the asymmetric N,O-alkylation protocol is a promising way to adjust the properties of the bislactam-containing conjugated polymers.

18.
Chemistry ; 24(39): 9807-9811, 2018 Jul 11.
Article in English | MEDLINE | ID: mdl-29691913

ABSTRACT

Thiazoloisoindigo, a novel structural variation of isoindigo, is for the first time utilized to synthesize conjugated polymers. The polymer based on thiazoloisoindigo merges the advantages of the one based on thienoisoindigo and diazaisoindigo; it not only exhibits a greatly redshifted UV/Vis absorption to the near-infrared region owing to its strong tendency to form quinoidal structures, similar to that based on thienoisoindigo, but also shows excellent ambipolar mobility (hole: 3.93, electron: 1.07 cm2 V-1 s-1 ) in organic field-effect transistors (OFETs), superior to that based on diazaisoindigo, showing the strong electron-withdrawing capability of thiazoloisoindigo.

19.
J Mater Chem B ; 6(1): 133-142, 2018 Jan 07.
Article in English | MEDLINE | ID: mdl-32254201

ABSTRACT

Although significant progress has been made in mussel-inspired antifouling coatings, most of them suffer from low mechanical stability. Herein, we present a facile and efficient method to fabricate mechanically robust mussel-inspired antifouling coatings. A polyvinyl alcohol (PVA)-based mussel-inspired coating material, which exhibits the highest adhesion capability (always at 5B level in a tape adhesion test based on the ASTM D3359 method) and excellent anti-abrasive properties (little mass loss after 1000 abrasion cycles), is used as a universal platform for further modification to introduce antifouling properties. Intriguingly, the hydroxyl groups in this PVA-based coating material are used as the anchor for the installation of either hydrophilic or hydrophobic segments (or both) via a grafting-to approach. Single modifiers, methoxypolyethylene glycol (MPEG), sodium 2-hydroxyethanesulfonate (SHS) and 1H,1H,2H,2H-perfluorooctan-1-ol (PFO), and complex modifiers, MPEG/PFO, are tethered onto the coating through an effective urethane bond formation reaction to endow the surfaces with antifouling efficacy. The functionalized surfaces are shown to be effective in preventing bovine serum albumin (BSA) adsorption and in reducing bacterial (Gram-positive bacteria S. aureus and Gram-negative bacteria E. coli) adhesion. More importantly, such modification does not influence the strong adhesion and excellent anti-abrasion properties of the coating. To the best of our knowledge, this is the first example of merging excellent mechanical properties and antifouling capability for mussel-inspired coatings, which might find niches in a broad range of applications in the industrial and biomedical fields.

20.
Proc Natl Acad Sci U S A ; 114(26): E5129-E5137, 2017 06 27.
Article in English | MEDLINE | ID: mdl-28607077

ABSTRACT

Selective oxidation of aliphatic C-H bonds in alkylphenols serves significant roles not only in generation of functionalized intermediates that can be used to synthesize diverse downstream chemical products, but also in biological degradation of these environmentally hazardous compounds. Chemo-, regio-, and stereoselectivity; controllability; and environmental impact represent the major challenges for chemical oxidation of alkylphenols. Here, we report the development of a unique chemomimetic biocatalytic system originated from the Gram-positive bacterium Corynebacterium glutamicum The system consisting of CreHI (for installation of a phosphate directing/anchoring group), CreJEF/CreG/CreC (for oxidation of alkylphenols), and CreD (for directing/anchoring group offloading) is able to selectively oxidize the aliphatic C-H bonds of p- and m-alkylated phenols in a controllable manner. Moreover, the crystal structures of the central P450 biocatalyst CreJ in complex with two representative substrates provide significant structural insights into its substrate flexibility and reaction selectivity.


Subject(s)
Bacterial Proteins/chemistry , Corynebacterium glutamicum/enzymology , Cytochrome P-450 Enzyme System/chemistry , Phenols/chemistry , Catalysis , Oxidation-Reduction
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