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1.
Acta Crystallogr C Struct Chem ; 76(Pt 3): 269-275, 2020 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-32132285

RESUMEN

A new iridoid glycoside, methyl (3R,4R,4aS,7S,7aR)-3-hydroxy-7-methyl-5-oxooctahydrocyclopenta[c]pyran-4-carboxylate-3-O-ß-D-(1'S,2'R,3'S,4'S,5'R)-glucopyranoside, named loniceroside A, C17H26O10, (1), was obtained from the aerial parts of Lonicera saccata. Its structure was established based on an analysis of spectroscopic data, including 1D NMR, 2D NMR and HRESIMS, and the configurations of the chiral C atoms were determined by X-ray crystallographic analysis. The single-crystal structure reveals that the cyclopenta[c]pyran scaffold is formed from a five-membered ring and a chair-like six-membered ring connected through two bridgehead chiral C atoms. In the solid state, the glucose group of (1) plays an important role in constructing an unusual supramolecular motif. The structure analysis revealed adjacent molecules linked together through intermolecular O-H...O hydrogen bonds to generate a banded structure. Furthermore, the banded structures are linked into a three-dimensional network by interesting hydrogen bonds. Biogenetically, compound (1) carries a glucopyranosyloxy moiety at the C-3 position, representing a rare structural feature for naturally occurring iridoid glycosides. The growth inhibitory effects against human cervical carcinoma cells (Hela), human lung adenocarcinoma cells (A549), human acute mononuclear granulocyte leukaemia (THP-1) and the human liver hepatocellular carcinoma cell line (HepG2) were evaluated by the MTT method.


Asunto(s)
Citotoxinas/farmacología , Glicósidos Iridoides/farmacología , Lonicera/química , Cristalografía por Rayos X , Citotoxinas/aislamiento & purificación , Humanos , Enlaces de Hidrógeno , Glicósidos Iridoides/aislamiento & purificación , Espectroscopía de Resonancia Magnética , Estructura Molecular
2.
Nature ; 579(7797): 152-157, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32076264

RESUMEN

GPR52 is a class-A orphan G-protein-coupled receptor that is highly expressed in the brain and represents a promising therapeutic target for the treatment of Huntington's disease and several psychiatric disorders1,2. Pathological malfunction of GPR52 signalling occurs primarily through the heterotrimeric Gs protein2, but it is unclear how GPR52 and Gs couple for signal transduction and whether a native ligand or other activating input is required. Here we present the high-resolution structures of human GPR52 in three states: a ligand-free state, a Gs-coupled self-activation state and a potential allosteric ligand-bound state. Together, our structures reveal that extracellular loop 2 occupies the orthosteric binding pocket and operates as a built-in agonist, conferring an intrinsically high level of basal activity to GPR523. A fully active state is achieved when Gs is coupled to GPR52 in the absence of an external agonist. The receptor also features a side pocket for ligand binding. These insights into the structure and function of GPR52 could improve our understanding of other self-activated GPCRs, enable the identification of endogenous and tool ligands, and guide drug discovery efforts that target GPR52.


Asunto(s)
Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/metabolismo , Regulación Alostérica , Sitio Alostérico , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Apoproteínas/agonistas , Apoproteínas/química , Apoproteínas/metabolismo , Sitios de Unión , Microscopía por Crioelectrón , Cristalografía por Rayos X , Subunidades alfa de la Proteína de Unión al GTP Gs/química , Subunidades alfa de la Proteína de Unión al GTP Gs/metabolismo , Subunidades alfa de la Proteína de Unión al GTP Gs/ultraestructura , Humanos , Ligandos , Modelos Moleculares , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/ultraestructura
3.
Viruses ; 12(2)2020 02 21.
Artículo en Inglés | MEDLINE | ID: mdl-32098094

RESUMEN

Porcine epidemic diarrhea virus (PEDV), being highly virulent and contagious in piglets, has caused significant damage to the pork industries of many countries worldwide. There are no commercial drugs targeting coronaviruses (CoVs), and few studies on anti-PEDV inhibitors. The coronavirus 3C-like protease (3CLpro) has a conserved structure and catalytic mechanism and plays a key role during viral polyprotein processing, thus serving as an appealing antiviral drug target. Here, we report the anti-PEDV effect of the broad-spectrum inhibitor GC376 (targeting 3Cpro or 3CLpro of viruses in the picornavirus-like supercluster). GC376 was highly effective against the PEDV 3CLpro and exerted similar inhibitory effects on two PEDV strains. Furthermore, the structure of the PEDV 3CLpro in complex with GC376 was determined at 1.65 Å. We elucidated structural details and analyzed the differences between GC376 binding with the PEDV 3CLpro and GC376 binding with the transmissible gastroenteritis virus (TGEV) 3CLpro. Finally, we explored the substrate specificity of PEDV 3CLpro at the P2 site and analyzed the effects of Leu group modification in GC376 on inhibiting PEDV infection. This study helps us to understand better the PEDV 3CLpro substrate specificity, providing information on the optimization of GC376 for development as an antiviral therapeutic against coronaviruses.


Asunto(s)
Antivirales/farmacología , Péptido Hidrolasas/química , Virus de la Diarrea Epidémica Porcina/efectos de los fármacos , Inhibidores de Proteasas/farmacología , Pirrolidinas/farmacología , Animales , Antivirales/química , Antivirales/metabolismo , Dominio Catalítico , Cristalografía por Rayos X , Modelos Moleculares , Péptido Hidrolasas/metabolismo , Virus de la Diarrea Epidémica Porcina/enzimología , Virus de la Diarrea Epidémica Porcina/fisiología , Inhibidores de Proteasas/química , Inhibidores de Proteasas/metabolismo , Pirrolidinas/química , Pirrolidinas/metabolismo , Especificidad por Sustrato , Virus de la Gastroenteritis Transmisible/enzimología , Células Vero , Replicación Viral/efectos de los fármacos
5.
Phytochemistry ; 172: 112282, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32036186

RESUMEN

Seventeen highly oxygenated and rearranged limonoids, including nine previously undescribed phragmalin-type limonoids with 1,8,9- and 8,9,30-orthesters (entanutilins C-K, 1-9), three undescribed limonoids with rare rearranged-6/6/7/5 skeleton (entanutilins L-N, 10-12), and 5 known limonoids, were isolated from the stem barks of Entandrophragma utile from Ghana (Africa). Their structures including absolute configurations were elucidated based on comprehensive spectroscopic analyses, such as HRESIMS, 1D/2D-NMR, CD exciton chirality method, time-dependent density functional theory (TDDFT)/ECD calculations, and single-crystal X-ray diffraction. Bioactivity screenings suggested that some of these compounds effectively reversed resistance in MCF-7/DOX cells at a nontoxic concentration of 30 µM with 6- to 19-fold enhancing effects.


Asunto(s)
Limoninas , Meliaceae , Cristalografía por Rayos X , Humanos , Espectroscopía de Resonancia Magnética , Estructura Molecular
6.
Phytochemistry ; 172: 112281, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32044582

RESUMEN

Ten undescribed highly oxidized sesquiterpenes and six known sesquiterpenes were isolated from H2O-soluble part of the fruits of Illicium lanceolatum A. C. Smith. The structures of undescribed compounds were elucidated by interpretation of spectroscopic data, and the absolute configurations of 2α-hydroxyneoanisatinic acid, (1R,5R,6S,7R,9R,10R)-3,4-dehydro-12-hydroxy-floridanolide, and (1R,4S,5R,6S,7S,9S)-1-deoxy-13-hydroxymerrilactone B were determined by the single-crystal X-ray diffraction analysis. Illilanceolatin A was the first example of a seco-prezizaane type sesquiterpene with a hemiacetal moiety located at C-10. 2α-Hydroxyneoanisatinic acid and anisatinic acid were two naturally occurring undescribed seco-prezizaane type sesquiterpenes with a 5/5/6 tricyclic carbon skeleton. Plausible biosynthetic pathways of the isolated polycyclic and highly oxidized sesquiterpenes derived from the intermediate allo-cedrane were proposed. (1R,5R,6S,7R,9R,10R)-3,4-dehydro-12-hydroxy-floridanolide, 1,3-dihydroxyneoanisatin, and 2α-hydroxyneoanisatin displayed neuroprotective effects with protection rates of 19.9, 22.7 and 24.3% at 10 µM, respectively. Additionally, the preliminary acute toxicity of anisatinic acid was also evaluated.


Asunto(s)
Illicium , Fármacos Neuroprotectores , Sesquiterpenos , Cristalografía por Rayos X , Frutas , Estructura Molecular
7.
Chem Commun (Camb) ; 56(14): 2186-2189, 2020 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-31971182

RESUMEN

The intrinsic l-DNA binding properties of a natural DNA polymerase was discovered. The binding affinity of Dpo4 polymerase for l-DNA was comparable to that for d-DNA. The crystal structure of Dpo4/l-DNA complex revealed a dimer formed by the little finger domain that provides a binding site for l-DNA.


Asunto(s)
ADN Polimerasa Dirigida por ADN/química , ADN/química , Cristalografía por Rayos X , ADN/metabolismo , ADN Polimerasa Dirigida por ADN/metabolismo , Modelos Moleculares , Conformación Proteica
8.
Emerg Microbes Infect ; 9(1): 58-66, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31894729

RESUMEN

Enzymes from the purine salvage pathway in Mycobacterium tuberculosis (Mtb) have been regarded as an attractive target for the development of anti-bacterial drugs. Although this pathway has not been extensively studied in Mtb, it has been identified as essential for growth and survival. Glycinamide-RNase-transformylase T (PurT) is found only in some specific bacteria including Mtb and utilizes ATP-dependent ligation to catalyze the formylation of 5'-phosphoribosyl-glycinamide (GAR) in the third reaction of the de novo purine salvage pathway. In the study, we determined the crystal structure of MtbPurT at a resolution of 2.79 Å. In contrast to Pyrococcus horikoshii OT3 PurT (phBCCPPurT), MtbPurT exhibits an "open" conformation, which results in a broader ATP-binding pocket and thus might facilitate the entry and exit of the cofactor. Additionally, active site superposition with E.coli PurT (EcPurT) showed that residues involved in the ATP-binding site in MtbPurT exhibited structural similarity but had notable difference in the GAR-binding site. The loop 383-389 in MtbPurT was much shorter and shifted 5.7 Å away from the phosphate of the GAR substrate. The different GAR-binding mode might result in a large conformational change in MtbPurT, and would provide a possible opportunity for anti-TB drug development.


Asunto(s)
Proteínas Bacterianas/química , Transferasas de Hidroximetilo y Formilo/química , Mycobacterium tuberculosis/enzimología , Proteínas Bacterianas/metabolismo , Cristalografía por Rayos X , Transferasas de Hidroximetilo y Formilo/metabolismo , Redes y Vías Metabólicas , Purinas/metabolismo
9.
Nucleic Acids Res ; 48(3): 1572-1582, 2020 02 20.
Artículo en Inglés | MEDLINE | ID: mdl-31919512

RESUMEN

BCDIN3 domain containing RNA methyltransferase, BCDIN3D, monomethylates the 5'-monophosphate of cytoplasmic tRNAHis with a G-1:A73 mispair at the top of an eight-nucleotide-long acceptor helix, using S-adenosyl-l-methionine (SAM) as a methyl group donor. In humans, BCDIN3D overexpression is associated with the tumorigenic phenotype and poor prognosis in breast cancer. Here, we present the crystal structure of human BCDIN3D complexed with S-adenosyl-l-homocysteine. BCDIN3D adopts a classical Rossmann-fold methyltransferase structure. A comparison of the structure with that of the closely related methylphosphate capping enzyme, MePCE, which monomethylates the 5'-γ-phosphate of 7SK RNA, revealed the important residues for monomethyl transfer from SAM onto the 5'-monophosphate of tRNAHis and for tRNAHis recognition by BCDIN3D. A structural model of tRNAHis docking onto BCDIN3D suggested the molecular mechanism underlying the different activities between BCDIN3D and MePCE. A loop in BCDIN3D is shorter, as compared to the corresponding region that forms an α-helix to recognize the 5'-end of RNA in MePCE, and the G-1:A73 mispair in tRNAHis allows the N-terminal α-helix of BCDIN3D to wedge the G-1:A73 mispair of tRNAHis. As a result, the 5'-monophosphate of G-1 of tRNAHis is deep in the catalytic pocket for 5'-phosphate methylation. Thus, BCDIN3D is a tRNAHis-specific 5'-monomethylphosphate capping enzyme that discriminates tRNAHis from other tRNA species, and the structural information presented in this study also provides the molecular basis for the development of drugs against breast cancers.


Asunto(s)
Metiltransferasas/ultraestructura , ARN de Transferencia de Histidina/ultraestructura , ARN de Transferencia/genética , S-Adenosilhomocisteína/química , Antineoplásicos/química , Antineoplásicos/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Cristalografía por Rayos X , Citoplasma/química , Citoplasma/genética , Femenino , Regulación Enzimológica de la Expresión Génica/genética , Humanos , Metilación , Metiltransferasas/química , Metiltransferasas/genética , Conformación Proteica en Hélice alfa , Pliegue de Proteína , ARN de Transferencia/química , ARN de Transferencia de Histidina/química , ARN de Transferencia de Histidina/genética
10.
J Enzyme Inhib Med Chem ; 35(1): 498-505, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31914836

RESUMEN

Brain butyrylcholinesterase (BChE) is an attractive target for drugs designed for the treatment of Alzheimer's disease (AD) in its advanced stages. It also potentially represents a biomarker for progression of this disease. Based on the crystal structure of previously described highly potent, reversible, and selective BChE inhibitors, we have developed the fluorescent probes that are selective towards human BChE. The most promising probes also maintain their inhibition of BChE in the low nanomolar range with high selectivity over acetylcholinesterase. Kinetic studies of probes reveal a reversible mixed inhibition mechanism, with binding of these fluorescent probes to both the free and acylated enzyme. Probes show environment-sensitive emission, and additionally, one of them also shows significant enhancement of fluorescence intensity upon binding to the active site of BChE. Finally, the crystal structures of probes in complex with human BChE are reported, which offer an excellent base for further development of this library of compounds.


Asunto(s)
Amidas/farmacología , Butirilcolinesterasa/metabolismo , Inhibidores de la Colinesterasa/farmacología , Colorantes Fluorescentes/farmacología , Amidas/síntesis química , Amidas/química , Animales , Butirilcolinesterasa/aislamiento & purificación , Inhibidores de la Colinesterasa/síntesis química , Inhibidores de la Colinesterasa/química , Cristalografía por Rayos X , Colorantes Fluorescentes/síntesis química , Colorantes Fluorescentes/química , Humanos , Ratones , Modelos Moleculares , Estructura Molecular
11.
Inorg Chem ; 59(2): 1242-1255, 2020 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-31910004

RESUMEN

Cytochrome c oxidase (CcO) has a binuclear active site composed of a high-spin heme group and a tris-histidine-ligated copper ion (CuB). By using two different porphyrin models derived by Gunter (H2TPyPP) and us (H2TImPP), we have isolated several mono- and binuclear complexes including one carbonyl and three chloride derivatives which are determined by 100 K single-crystal X-ray. Low-temperature (4 K) EPR and multitemperature (295-25 K) Mössbauer investigations on the products not only confirmed the spin states of the two metal ions (S = 5/2 Fe3+ and S = 1/2 Cu2+) but also revealed the intermolecular interactions and intramolecular couplings which are in accordance with the crystal structural features.


Asunto(s)
Complejo IV de Transporte de Electrones/análisis , Porfirinas/química , Cristalografía por Rayos X , Complejo IV de Transporte de Electrones/metabolismo , Modelos Moleculares , Estructura Molecular , Porfirinas/metabolismo , Temperatura Ambiental
12.
Nucleic Acids Res ; 48(4): 2026-2034, 2020 02 28.
Artículo en Inglés | MEDLINE | ID: mdl-31943070

RESUMEN

Type II CRISPR-Cas9 RNA-guided nucleases are widely used for genome engineering. Type II-A SpCas9 protein from Streptococcus pyogenes is the most investigated and highly used enzyme of its class. Nevertheless, it has some drawbacks, including a relatively big size, imperfect specificity and restriction to DNA targets flanked by an NGG PAM sequence. Cas9 orthologs from other bacterial species may provide a rich and largely untapped source of biochemical diversity, which can help to overcome the limitations of SpCas9. Here, we characterize CcCas9, a Type II-C CRISPR nuclease from Clostridium cellulolyticum H10. We show that CcCas9 is an active endonuclease of comparatively small size that recognizes a novel two-nucleotide PAM sequence. The CcCas9 can potentially broaden the existing scope of biotechnological applications of Cas9 nucleases and may be particularly advantageous for genome editing of C. cellulolyticum H10, a bacterium considered to be a promising biofuel producer.


Asunto(s)
Proteína 9 Asociada a CRISPR/química , Sistemas CRISPR-Cas/genética , Clostridium cellulolyticum/enzimología , ADN/química , Proteína 9 Asociada a CRISPR/genética , Cristalografía por Rayos X , ADN/genética , Edición Génica , Mutación , Motivos de Nucleótidos/genética , ARN Guia/genética , Streptococcus pyogenes/enzimología , Especificidad por Sustrato
13.
Nucleic Acids Res ; 48(4): 2144-2155, 2020 02 28.
Artículo en Inglés | MEDLINE | ID: mdl-31965171

RESUMEN

Reiterative transcription is a non-canonical form of RNA synthesis by RNA polymerase in which a ribonucleotide specified by a single base in the DNA template is repetitively added to the nascent RNA transcript. We previously determined the X-ray crystal structure of the bacterial RNA polymerase engaged in reiterative transcription from the pyrG promoter, which contains eight poly-G RNA bases synthesized using three C bases in the DNA as a template and extends RNA without displacement of the promoter recognition σ factor from the core enzyme. In this study, we determined a series of transcript initiation complex structures from the pyrG promoter using soak-trigger-freeze X-ray crystallography. We also performed biochemical assays to monitor template DNA translocation during RNA synthesis from the pyrG promoter and in vitro transcription assays to determine the length of poly-G RNA from the pyrG promoter variants. Our study revealed how RNA slips on template DNA and how RNA polymerase and template DNA determine length of reiterative RNA product. Lastly, we determined a structure of a transcript initiation complex at the pyrBI promoter and proposed an alternative mechanism of RNA slippage and extension requiring the σ dissociation from the core enzyme.


Asunto(s)
Ligasas de Carbono-Nitrógeno/química , ARN Polimerasas Dirigidas por ADN/química , ARN Bacteriano/química , Transcripción Genética , Bacillus subtilis/química , Bacillus subtilis/genética , Ligasas de Carbono-Nitrógeno/genética , Cristalografía por Rayos X , ADN/química , ADN/genética , ARN Polimerasas Dirigidas por ADN/genética , Escherichia coli/genética , Regulación Bacteriana de la Expresión Génica/genética , Regiones Promotoras Genéticas/genética , ARN Bacteriano/genética , Factor sigma/química , Factor sigma/genética , Uridina Trifosfato/química , Uridina Trifosfato/genética
14.
Nat Commun ; 11(1): 140, 2020 01 09.
Artículo en Inglés | MEDLINE | ID: mdl-31919415

RESUMEN

Antimicrobial resistance is a major global threat that calls for new antibiotics. Globomycin and myxovirescin are two natural antibiotics that target the lipoprotein-processing enzyme, LspA, thereby compromising the integrity of the bacterial cell envelope. As part of a project aimed at understanding their mechanism of action and for drug development, we provide high-resolution crystal structures of the enzyme from the human pathogen methicillin-resistant Staphylococcus aureus (MRSA) complexed with globomycin and with myxovirescin. Our results reveal an instance of convergent evolution. The two antibiotics possess different molecular structures. Yet, they appear to inhibit identically as non-cleavable tetrahedral intermediate analogs. Remarkably, the two antibiotics superpose along nineteen contiguous atoms that interact similarly with LspA. This 19-atom motif recapitulates a part of the substrate lipoprotein in its proposed binding mode. Incorporating this motif into a scaffold with suitable pharmacokinetic properties should enable the development of effective antibiotics with built-in resistance hardiness.


Asunto(s)
Ácido Aspártico Endopeptidasas/metabolismo , Proteínas Bacterianas/metabolismo , Macrólidos/metabolismo , Staphylococcus aureus Resistente a Meticilina/enzimología , Péptidos/metabolismo , Sitios de Unión/fisiología , Membrana Celular/efectos de los fármacos , Cristalografía por Rayos X , Farmacorresistencia Bacteriana/genética , Farmacorresistencia Bacteriana/fisiología , Macrólidos/farmacología , Péptidos/farmacología , Unión Proteica/fisiología , Estructura Terciaria de Proteína
15.
Acta Crystallogr C Struct Chem ; 76(Pt 1): 1-9, 2020 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-31919301

RESUMEN

Depsipeptides and cyclodepsipeptides are analogues of the corresponding peptides in which one or more amide groups are replaced by ester functions. Reports of crystal structures of linear depsipeptides are rare. The crystal structures and conformational analyses of four depsipeptides with an alternating sequence of an α,α-disubstituted α-amino acid and an α-hydroxy acid are reported. The molecules in the linear hexadepsipeptide amide in (S)-Pms-Acp-(S)-Pms-Acp-(S)-Pms-Acp-NMe2 acetonitrile solvate, C47H58N4O9·C2H3N, (3b), as well as in the related linear tetradepsipeptide amide (S)-Pms-Aib-(S)-Pms-Aib-NMe2, C28H37N3O6, (5a), the diastereoisomeric mixture (S,R)-Pms-Acp-(R,S)-Pms-Acp-NMe2/(R,S)-Pms-Acp-(R,S)-Pms-Acp-NMe2 (1:1), C32H41N3O6, (5b), and (R,S)-Mns-Acp-(S,R)-Mns-Acp-NMe2, C30H37N3O6, (5c) (Pms is phenyllactic acid, Acp is 1-aminocyclopentanecarboxylic acid and Mns is mandelic acid), generally adopt a ß-turn conformation in the solid state, which is stabilized by intramolecular N-H...O hydrogen bonds. Whereas ß-turns of type I (or I') are formed in the cases of (3b), (5a) and (5b), which contain phenyllactic acid, the torsion angles for (5c), which incorporates mandelic acid, indicate a ß-turn in between type I and type III. Intermolecular N-H...O and O-H...O hydrogen bonds link the molecules of (3a) and (5b) into extended chains, and those of (5a) and (5c) into two-dimensional networks.


Asunto(s)
Aminoácidos/química , Depsipéptidos/química , Hidroxiácidos/química , Amidas/química , Cristalografía por Rayos X , Enlaces de Hidrógeno , Conformación Proteica , Análisis Espectral/métodos
16.
Acta Crystallogr C Struct Chem ; 76(Pt 1): 44-63, 2020 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-31919307

RESUMEN

Eight novel Schiff bases derived from benzil dihydrazone (BDH) or benzil monohydrazone (BMH) and four fused-ring carbonyl compounds (3-formylindole, FI; 3-acetylindole, AI; 3-formyl-1-methylindole, MFI; 1-formylnaphthalene, FN) were synthesized and characterized by elemental analysis, ESI-QTOF-MS, 1H and 13C NMR spectroscopy, as well as single-crystal X-ray diffraction. They are (1Z,2Z)-1,2-bis{(E)-[(1H-indol-3-yl)methylidene]hydrazinylidene}-1,2-diphenylethane (BDHFI), C32H24N6, (1Z,2Z)-1,2-bis{(E)-[1-(1H-indol-3-yl)ethylidene]hydrazinylidene}-1,2-diphenylethane (BDHAI), C34H28N6, (1Z,2Z)-1,2-bis{(E)-[(1-methyl-1H-indol-3-yl)methylidene]hydrazinylidene}-1,2-diphenylethane (BMHMFI) acetonitrile hemisolvate, C34H28N6·0.5CH3CN, (1Z,2Z)-1,2-bis{(E)-[(naphthalen-1-yl)methylidene]hydrazinylidene}-1,2-diphenylethane (BDHFN), C36H26N4, (Z)-2-{(E)-[(1H-indol-3-yl)methylidene]hydrazinylidene}-1,2-diphenylethanone (BMHFI), C23H17N3O, (Z)-2-{(E)-[1-(1H-indol-3-yl)ethylidene]hydrazinylidene}-1,2-diphenylethanone (BMHAI), C24H19N3O, (Z)-2-{(E)-[(1-methyl-1H-indol-3-yl)methylidene]hydrazinylidene}-1,2-diphenylethanone (BMHMFI), C24H19N3O, and (Z)-2-{(E)-[(naphthalen-1-yl)methylidene]hydrazinylidene}-1,2-diphenylethanone (BMHFN) C25H18N2O. Moreover, the in vitro cytotoxicity of the eight title compounds was evaluated against two tumour cell lines (A549 human lung cancer and 4T1 mouse breast cancer) and two normal cell lines (MRC-5 normal lung cells and NIH 3T3 fibroblasts) by MTT assay. The results indicate that four (BDHMFI, BDHFN, BMHMFI and BMHFN) are inactive and the other four (BDHFI, BDHAI, BMHFI and BMHAI) show severe toxicities against human A549 and mouse 4T1 cells, similar to the standard cisplatin. All the compounds exhibited weaker cytotoxicity against normal cells than cancer cells. The Swiss Target Prediction web server was applied for the prediction of protein targets. After analyzing the differences in frequency hits between these active and inactive Schiff bases, 18 probable targets were selected for reverse docking with the Surflex-dock function in SYBYL-X 2.0 software. Three target proteins, i.e. human ether-á-go-go-related (hERG) potassium channel, the inhibitor of apoptosis protein 3 and serine/threonine-protein kinase PIM1, were chosen as the targets. Finally, the ligand-based structure-activity relationships were analyzed based on the putative protein target (hERG) docking results, which will be used to design and synthesize novel hERG ion channel inhibitors.


Asunto(s)
Proliferación Celular/efectos de los fármacos , Fenilglioxal/análogos & derivados , Bases de Schiff/química , Animales , Línea Celular Tumoral , Cristalografía por Rayos X/métodos , Humanos , Ratones , Simulación del Acoplamiento Molecular , Estructura Molecular , Células 3T3 NIH , Fenilglioxal/química , Fenilglioxal/farmacología , Bases de Schiff/farmacología , Relación Estructura-Actividad
17.
Acta Crystallogr C Struct Chem ; 76(Pt 1): 69-74, 2020 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-31919309

RESUMEN

The title benzothiazine-3-carboxamide, C17H16N2O4S, crystallized in two enantiomorphic crystal forms with the space groups P32 and P31 despite the absence of a classic stereogenic atom. The molecular structures are mirror images of each other. Only one sulfonyl O atom takes part in intramolecular hydrogen bonding as a proton acceptor and this atom is different in the two enantiomorphic structures. As a result, the S atom becomes a pseudo-stereogenic centre. This fact is worth taking into account due to the different biological activities of the enantiomorphic forms. One form possesses a high analgesic activity, while the other form revealed a high anti-inflammatory activity.


Asunto(s)
Antiinflamatorios no Esteroideos/química , Piroxicam/análogos & derivados , Cristalografía por Rayos X , Enlaces de Hidrógeno , Estructura Molecular , Estereoisomerismo
18.
Acta Crystallogr C Struct Chem ; 76(Pt 1): 87-92, 2020 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-31919311

RESUMEN

1,3-Enyne structural motifs are versatile building blocks in organic synthesis and occur widely in various natural products with many of them being highly active as cytotoxic macrolides and antitumour antibiotics. This article presents the crystal structure of three 1,1,4-triphenyl-substituted 1,3-enynes, viz. 4-(2-methylphenyl)-1,1-diphenylbut-1-en-3-yne, C23H18 (1), 4-(2-methoxyphenyl)-1,1-diphenylbut-1-en-3-yne, C23H18O (2), and 4-(4-nitrophenyl)-1,1-diphenylbut-1-en-3-yne, C22H15NO2 (3). The benzene ring at position 4 of the but-1-en-3-yne group bears a weakly activating methyl group in compound 1, a moderately activating methoxy group in 2 and a strongly deactivating nitro group in 3. The crystal structures of 1 and 3 both have monoclinic symmetry, while that of 2 is orthorhombic, and all of them have one molecule in the asymmetric unit. All three compounds were investigated for their antibacterial and antifungal activities. Interestingly, enyne 2 is the only compound tested that inhibited the growth of Aspergillus niger.


Asunto(s)
Cristalografía por Rayos X/métodos , Hidrocarburos/química , Antibacterianos/química , Antifúngicos/química , Estructura Molecular
19.
Phys Chem Chem Phys ; 22(5): 2999-3007, 2020 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-31957771

RESUMEN

Infrared multiple photon dissociation (IRMPD) spectroscopy has been used to probe the structures of the three protonated base-pair mismatches containing 9-ethylguanine (9eG) in the gas phase. Computational chemistry has been used to determine the relative energies and compute the infrared spectra of these complexes. By comparing the IRMPD spectra with the computed spectra, in all cases, it was possible to deduce that what was observed experimentally were the lowest energy computed structures. The protonated complex between 9eG and 1-methylthymine (1mT) is protonated at N7 of 9eG-the most basic site of all three bases in this study-and bound in a Hoogsteen type structure with two hydrogen bonds. The experimental IRMPD spectrum for the protonated complex between 9eG and 9-methyladenine (9mA) is described as arising from a combination of the two lowest energy structures, both which are protonated at N1 of adenine and each containing two hydrogen bonds with 9eG being the acceptor of both. The protonated dimer of 9eG is protonated at N7 with an N7-H+-N7 ionic hydrogen bond. It also contains an interaction between a C-H of protonated guanine and the O6 carbonyl of neutral guanine which is manifested in a slight red shift of that carbonyl stretch. The protonated 9eG/9mA structures have been previously identified by X-ray crystallography in RNA and are contained within the protein database.


Asunto(s)
Gases/química , Guanina/análogos & derivados , Espectrofotometría Infrarroja , Adenina/análogos & derivados , Adenina/química , Adenina/metabolismo , Disparidad de Par Base , Cristalografía por Rayos X , Guanina/química , Guanina/metabolismo , Enlaces de Hidrógeno , Modelos Moleculares , Fotones , Timina/análogos & derivados , Timina/química , Timina/metabolismo
20.
Appl Microbiol Biotechnol ; 104(5): 2051-2066, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31930452

RESUMEN

Looking for new ene-reductases with uncovered features beneficial for biotechnological applications, by mining genomes of photosynthetic extremophile organisms, we identified two new Old Yellow Enzyme homologues: CtOYE, deriving from the cyanobacterium Chroococcidiopsis thermalis, and GsOYE, from the alga Galdieria sulphuraria. Both enzymes were produced and purified with very good yields and displayed catalytic activity on a broad substrate spectrum by reducing α,ß-unsaturated ketones, aldehydes, maleimides and nitroalkenes with good to excellent stereoselectivity. Both enzymes prefer NADPH but demonstrate a good acceptance of NADH as cofactor. CtOYE and GsOYE represent robust biocatalysts showing high thermostability, a wide range of pH optimum and good co-solvent tolerance. High resolution X-ray crystal structures of both enzymes have been determined, revealing conserved features of the classical OYE subfamily as well as unique properties, such as a very long loop entering the active site or an additional C-terminal alpha helix in GsOYE. Not surprisingly, the active site of CtOYE and GsOYE structures revealed high affinity toward anions caught from the mother liquor and trapped in the anion hole where electron-withdrawing groups such as carbonyl group are engaged. Ligands (para-hydroxybenzaldehyde and 2-methyl-cyclopenten-1-one) added on purpose to study complexes of GsOYE were detected in the enzyme catalytic cavity, stacking on top of the FMN cofactor, and support the key role of conserved residues and FMN cofactor in the catalysis.


Asunto(s)
Extremófilos/enzimología , NADPH Deshidrogenasa/química , NADPH Deshidrogenasa/metabolismo , Alquenos/metabolismo , Biocatálisis , Dominio Catalítico , Cristalografía por Rayos X , Cianobacterias/enzimología , Cianobacterias/genética , Cianobacterias/metabolismo , Bases de Datos Genéticas , Estabilidad de Enzimas , Extremófilos/genética , Extremófilos/metabolismo , Mononucleótido de Flavina/metabolismo , Cinética , Modelos Moleculares , NADP/metabolismo , NADPH Deshidrogenasa/genética , NADPH Deshidrogenasa/aislamiento & purificación , Oxidación-Reducción , Conformación Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Rhodophyta/enzimología , Rhodophyta/genética , Especificidad por Sustrato
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