Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 6.081
Filtrar
1.
Life Sci Alliance ; 6(1)2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36319062

RESUMO

Ferroptosis is triggered by the breakdown of cellular iron-dependent redox homeostasis and the abnormal accumulation of lipid ROS. Cells have evolved defense mechanisms to prevent lipid ROS accumulation and ferroptosis. Using a library of more than 4,000 bioactive compounds, we show that tanshinone from Salvia miltiorrhiza (Danshen) has very potent inhibitory activity against ferroptosis. Mechanistically, we found that tanshinone functions as a coenzyme for NAD(P)H:quinone oxidoreductase 1 (NQO1), which detoxifies lipid peroxyl radicals and inhibits ferroptosis both in vitro and in vivo. Although NQO1 is recognized as an oxidative stress response gene, it does not appear to have a direct role in ferroptosis inhibition in the absence of tanshinone. Here, we demonstrate a gain of function of NQO1 induced by tanshinone, which is a novel mechanism for ferroptosis inhibition. Using mouse models of acute liver injury and ischemia/reperfusion heart injury, we observed that tanshinone displays protective effects in both the liver and the heart in a manner dependent on NQO1. Our results link the clinical use of tanshinone to its activity in ferroptosis inhibition.


Assuntos
Ferroptose , Salvia miltiorrhiza , Animais , Camundongos , Coenzimas/metabolismo , Mutação com Ganho de Função , Lipídeos , Espécies Reativas de Oxigênio/metabolismo , Salvia miltiorrhiza/metabolismo
2.
Proc Natl Acad Sci U S A ; 119(48): e2207965119, 2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36417431

RESUMO

Nucleobase-containing coenzymes are hypothesized to be relics of an early RNA-based world that preceded the emergence of proteins. Despite the importance of coenzyme-protein synergisms, their emergence and evolution remain understudied. An excellent target to address this issue is the Rossmann fold, the most catalytically diverse and abundant protein architecture in nature. We investigated two main Rossmann lineages: the nicotinamide adenine dinucleotide phosphate (NAD(P)) and the S-adenosyl methionine (SAM)- binding superfamilies. To identify the evolutionary changes that lead to a coenzyme specificity switch on these superfamilies, we performed structural and sequence-based Hidden Markov model analysis to systematically search for key motifs in their coenzyme-binding pockets. Our analyses revealed that through insertions and deletions (InDels) and a residue substitution, the ancient ß1-loop-α1 coenzyme-binding structure of NAD(P) could be reshaped into the SAM-binding ß1-loop-α1 structure. To experimentally prove this obsevation, we removed three amino acids from the NAD(P)-binding pocket and solved the structure of the resulting mutant, revealing the characteristic loop features of the SAM-binding pocket. To confirm the binding to SAM, we performed isothermal titration calorimetry measurements. Molecular dynamics simulations also corroborated the role of InDels in abolishing NAD binding and acquiring SAM binding. Our results uncovered how nature may have utilized insertions and deletions to optimize the different coenzyme-binding pockets and the distinct functionalities observed for Rossmann superfamilies. This work also proposes a general mechanism by which protein templates could have been recycled through the course of evolution to adopt different coenzymes and confer distinct chemistries.


Assuntos
Coenzimas , NAD , NAD/metabolismo , Proteínas/química , NADP/metabolismo , S-Adenosilmetionina
3.
J Oleo Sci ; 71(10): 1469-1480, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36184461

RESUMO

Flavonoid compounds are a group of polyphenolic molecules that are in vegetables, fruit, and grain. Laboratory studies and epidemiological investigations have indicated diverse beneficial biochemical properties of flavonoids, including anticancer, anti-inflammation, anti-oxidation, and anti-osteoporosis. We have recorded results for the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) Reductase and urease enzymes at the µM level. In this search, inhibition results of Panicolin on HMG-CoA reductase and tyrosinase enzymes recorded lower values of 113.98±14.38 and 2.57±0.20 µg /mL, respectively. Additionally, inhibition results of Panicolin on urease and α-amylase showed good values of 64.20±7.43 and 15.92±2.81 µg/mL, respectively. The chemical activities of panicolin against α-amylase, urease, tyrosinase, and HMG-CoA reductase, were determined by performing the molecular modeling study. The anti-cancer activities of panicolin were investigated against HL-60, THP-1, K562, and Molt-4 cell lines and IC50 values of Panicolin on these cell lines were obtained 12.94±1.04, 63.17±5.81, 15.05±1.02, and 10.84±0.65 µg/mL, respectively. The chemical activities of this compound against some of the expressed surface receptor proteins (Platelet-activating factor receptor, CD13, transferrin receptor, and CD44) in the cell lines were evaluated using molecular modeling calculations. The results revealed the possible interactions and their features at an atomic level. The docking scores suggested that panicolin has a significant binding affinity to the enzymes and proteins. Moreover, this compound constructed strong contacts with the enzymes and receptors. Therefore, panicolin could be a potential inhibitor for enzymes and cancer cells.


Assuntos
Leucemia , Neoplasias , Coenzima A , Coenzimas , Flavonoides , Humanos , Monofenol Mono-Oxigenase , Oxirredutases , Receptores da Transferrina , Urease , alfa-Amilases
4.
Molecules ; 27(19)2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36235107

RESUMO

The molybdenum cofactor (Moco) is the active site prosthetic group found in numerous vitally important enzymes (Mo-enzymes), which predominantly catalyze 2 electron transfer reactions. Moco is synthesized by an evolutionary old and highly conserved multi-step pathway, whereby the metal insertion reaction is the ultimate reaction step here. Moco and its intermediates are highly sensitive towards oxidative damage and considering this, they are believed to be permanently protein bound during synthesis and also after Moco maturation. In plants, a cellular Moco transfer and storage system was identified, which comprises proteins that are capable of Moco binding and release but do not possess a Moco-dependent enzymatic activity. The first protein described that exhibited these properties was the Moco carrier protein (MCP) from the green alga Chlamydomonas reinhardtii. However, MCPs and similar proteins have meanwhile been described in various plant species. This review will summarize the current knowledge of the cellular Moco distribution system.


Assuntos
Chlamydomonas reinhardtii , Metaloproteínas , Proteínas de Transporte/metabolismo , Domínio Catalítico , Chlamydomonas reinhardtii/metabolismo , Coenzimas/química , Metaloproteínas/química , Molibdênio/metabolismo , Cofatores de Molibdênio , Plantas/metabolismo
5.
Molecules ; 27(20)2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36296488

RESUMO

Molybdenum cofactor (Moco) deficiency (MoCD) is characterized by neonatal-onset myoclonic epileptic encephalopathy and dystonia with cerebral MRI changes similar to hypoxic-ischemic lesions. The molecular cause of the disease is the loss of sulfite oxidase (SOX) activity, one of four Moco-dependent enzymes in men. Accumulating toxic sulfite causes a secondary increase of metabolites such as S-sulfocysteine and thiosulfate as well as a decrease in cysteine and its oxidized form, cystine. Moco is synthesized by a three-step biosynthetic pathway that involves the gene products of MOCS1, MOCS2, MOCS3, and GPHN. Depending on which synthetic step is impaired, MoCD is classified as type A, B, or C. This distinction is relevant for patient management because the metabolic block in MoCD type A can be circumvented by administering cyclic pyranopterin monophosphate (cPMP). Substitution therapy with cPMP is highly effective in reducing sulfite toxicity and restoring biochemical homeostasis, while the clinical outcome critically depends on the degree of brain injury prior to the start of treatment. In the absence of a specific treatment for MoCD type B/C and SOX deficiency, we summarize recent progress in our understanding of the underlying metabolic changes in cysteine homeostasis and propose novel therapeutic interventions to circumvent those pathological changes.


Assuntos
Encefalopatias , Metaloproteínas , Sulfito Oxidase , Masculino , Recém-Nascido , Humanos , Cisteína , Tiossulfatos , Cistina , Coenzimas/metabolismo , Metaloproteínas/metabolismo , Sulfito Oxidase/genética , Sulfitos , Cofatores de Molibdênio , Molibdênio
6.
J Am Chem Soc ; 144(42): 19248-19252, 2022 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-36219699

RESUMO

Extant proteins exploit thermodynamically activated negatively charged coenzymes and hydrotropes to temporally access mechanistically important conformations that regulate vital biological functions, from metabolic reactions to expression modulation. Herein, we show that a short amyloid peptide can bind to a small molecular coenzyme by exploiting reversible covalent linkage to polymerize and access catalytically proficient nonequilibrium amyloid microphases. Subsequent hydrolysis of the activated coenzyme leads to depolymerization, realizing a variance of the surface charge of the assembly as a function of time. Such temporal change of surface charge dynamically modulates catalytic activities of the transient assemblies as observed in highly evolved modern-day biocatalysts.


Assuntos
Amiloide , Polímeros , Polímeros/química , Catálise , Amiloide/química , Proteínas Amiloidogênicas , Coenzimas , Peptídeos
7.
Int J Mol Sci ; 23(20)2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36293182

RESUMO

A balanced and varied diet provides diverse beneficial effects on health, such as adequate micronutrient availability and a gut microbiome in homeostasis. Besides their participation in biochemical processes as cofactors and coenzymes, vitamins and minerals have an immunoregulatory function; meanwhile, gut microbiota and its metabolites coordinate directly and indirectly the cell response through the interaction with the host receptors. Malnourishment is a crucial risk factor for several pathologies, and its involvement during the Coronavirus Disease 2019 pandemic has been reported. This pandemic has caused a significant decline in the worldwide population, especially those with chronic diseases, reduced physical activity, and elder age. Diet and gut microbiota composition are probable causes for this susceptibility, and its supplementation can play a role in reestablishing microbial homeostasis and improving immunity response against Coronavirus Disease 2019 infection and recovery. This study reviews the role of micronutrients and microbiomes in the risk of infection, the severity of disease, and the Coronavirus Disease 2019 sequelae.


Assuntos
COVID-19 , Microbioma Gastrointestinal , Humanos , Idoso , Micronutrientes/farmacologia , Vitaminas/farmacologia , Coenzimas
8.
Front Cell Infect Microbiol ; 12: 980157, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36159649

RESUMO

Post-treatment apical periodontitis (PoAP) occurs when root canal treatment has not adequately eliminated bacterial invasion and infection. Yet little is known about the bacterial composition and changes related to the etiology and pathogenesis of PoAP. In this study, clinical samples classified as root apex (HARD) and periapical granulation tissues (SOFT) were separately collected from 10 patients with PoAP. The microbiota of each sample was characterized by 16S rRNA gene sequencing, and the obtained dataset was coanalyzed with 20 NCBI sequence read archive (SRA) datasets of healthy oral (HO) and primary apical periodontitis (PAP). We observed 2522 operational taxonomic units (OTUs) belonging to 29 phyla, and all samples shared 86.5% of the sequence reads. The OTUs affiliated with Bacteroidetes, Firmicutes, Proteobacteria, Fusobacteria, and Actinobacteria, were identified as core microbiota, which accounted for nearly 90% of 16S rRNA sequences in all samples. However, the principal coordinates analysis (PCoA) of the beta diversity demonstrated that the three periapical statuses have distinct microbial compositions. Compared with HO and PoAP, Actinomyces has a significantly increased abundance in PAP. The microbial diversities in PoAP were significantly lower than those in the HO and PAP (p<0.05). The relative abundance of most bacterial taxa was decreasing, except that Clostridia and Synergistia were increased. Furthermore, we explored the potential metabolic differences of the microbial communities by KEGG pathway prediction. We revealed that the microbiota of PoAP might have a more active metabolic capacity, including carbohydrate metabolism, energy metabolism, and enzyme cofactor/carrier biosynthesis (p<0.05). Our study revealed that invasion of opportunistic pathogens such as Clostridia and Synergistia might play a significant role in PoAP, thus guiding the further study of complex microbial-host interactions and the development of more effective diagnostic and therapeutic methods.


Assuntos
Microbiota , Periodontite Periapical , Bactérias/genética , Coenzimas , DNA Bacteriano/análise , DNA Bacteriano/genética , Firmicutes/genética , Humanos , Microbiota/genética , Periodontite Periapical/microbiologia , Periodontite Periapical/terapia , RNA Ribossômico 16S/genética
9.
Molecules ; 27(17)2022 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-36080140

RESUMO

For most organisms molybdenum is essential for life as it is found in the active site of various vitally important molybdenum dependent enzymes (Mo-enzymes). Here, molybdenum is bound to a pterin derivative called molybdopterin (MPT), thus forming the molybdenum cofactor (Moco). Synthesis of Moco involves the consecutive action of numerous enzymatic reaction steps, whereby molybdenum insertases (Mo-insertases) catalyze the final maturation step, i.e., the metal insertion reaction yielding Moco. This final maturation step is subdivided into two partial reactions, each catalyzed by a distinctive Mo-insertase domain. Initially, MPT is adenylylated by the Mo-insertase G-domain, yielding MPT-AMP which is used as substrate by the E-domain. This domain catalyzes the insertion of molybdate into the MPT dithiolene moiety, leading to the formation of Moco-AMP. Finally, the Moco-AMP phosphoanhydride bond is cleaved by the E-domain to liberate Moco from its synthesizing enzyme. Thus formed, Moco is physiologically active and may be incorporated into the different Mo-enzymes or bind to carrier proteins instead.


Assuntos
Metaloproteínas , Molibdênio , Monofosfato de Adenosina , Domínio Catalítico , Coenzimas/química , Metaloproteínas/química , Molibdênio/metabolismo , Cofatores de Molibdênio , Pterinas
10.
Environ Res ; 215(Pt 3): 114427, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36179884

RESUMO

The capacity to generate a constant signal response from an enzyme on an electrode surface has been a fascinating topic of research from the past three decades. To nourish the enzymatic activity during electrochemical reactions, the immobilization of dual enzymes on the electrode surface could prevent the enzymatic loss without denaturation and thus long-term stability can be achieved. For effective immobilization of dual enzymes, mesoporous materials are the ideal choice because of its numerous advantages such as 1. The presence of porous structure facilitates high loading of enzymes 2. The formation of protective environment can withstand the enzymatic activity even at acidic or basic pH values and even at elevated temperatures. Herein, we develop bienzymatic immobilization of horseradish peroxidase (HRP) and cholesterol oxidase (ChOx) on mesoporous V2O5-TiO2 based binary nanocomposite for effective sensing of hydrogen peroxide (H2O2) in presence of redox mediator hydroquinone (HQ). The utilization of redox mediator in second-generation biosensing of H2O2 can eliminate the interference species and reduces the operating potential with higher current density for electrochemical reduction reaction. Using this mediator transfer process approach at HRP/ChOx/V2O5-TiO2 modified GC, the H2O2 can be determined at operating potential (-0.2 V) with good linear range (0.05-3.5 mM) higher sensitivity (1040 µAµM-1 cm-2) and lower detection limit of about 20 µM can be attained, which is due to higher mediation of electrons were transferred to the enzyme cofactors. These interesting characteristics could be due to mesoporous structure of V2O5-TiO2 can induce large immobilization and facilitate higher interaction with enzymes for wide range of biosensing applications.


Assuntos
Técnicas Biossensoriais , Peróxido de Hidrogênio , Colesterol Oxidase , Coenzimas , Enzimas Imobilizadas/química , Peroxidase do Rábano Silvestre/química , Peróxido de Hidrogênio/química , Hidroquinonas , Titânio
11.
Microbiol Res ; 265: 127200, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36162148

RESUMO

The incidence of intra-abdominal candidiasis (IAC), characterized by high morbidity and mortality, has become a serious concern. The limitations of current antifungal drugs on the market underscores the importance of the development of novel antifungal agents. In the present study, the antifungal activity of vitamin D3 (VD3) against various Candida species was investigated. In vitro, the broth microdilution method and solid plate assay confirmed that VD3 inhibited the growth of Candida spp. in a broad-spectrum, dose-dependent manner. VD3 also had a significant antifungal effect on the initiation, development, and maturation phases of biofilm formation in Candida albicans. The mechanism of VD3 action was explored by transcriptomics and reverse transcription quantitative PCR (RT-qPCR) analysis, and showed that VD3 affects ribosome biogenesis, coenzyme metabolism, and carbon metabolism. These results suggested that VD3 may have multitarget effects against C. albicans. In the murine IAC model, VD3 reduced the fungal burden in the liver, kidneys, and small intestine. Further histopathological analysis and quantification of plasma cytokine levels confirmed that VD3 treatment significantly decreased the infiltration of inflammatory cells and the levels of plasma interferon (IFN)-γ and tumor necrosis factor (TNF)-α. Taken together, these findings suggest a new antifungal mechanism for VD3 and indicate that VD3 could be an effective therapeutic agent for use in IAC treatment.


Assuntos
Candida albicans , Candidíase , Animais , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Candida , Candidíase/tratamento farmacológico , Candidíase/microbiologia , Carbono , Colecalciferol/farmacologia , Coenzimas/farmacologia , Citocinas , Interferons/farmacologia , Camundongos , Testes de Sensibilidade Microbiana , Fatores de Necrose Tumoral/farmacologia
12.
Nat Prod Rep ; 39(11): 2175-2199, 2022 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-36149232

RESUMO

Covering: up to 2022The report provides a broad approach to deciphering the evolution of coenzyme biosynthetic pathways. Here, these various pathways are analyzed with respect to the coenzymes required for this purpose. Coenzymes whose biosynthesis relies on a large number of coenzyme-mediated reactions probably appeared on the scene at a later stage of biological evolution, whereas the biosyntheses of pyridoxal phosphate (PLP) and nicotinamide (NAD+) require little additional coenzymatic support and are therefore most likely very ancient biosynthetic pathways.


Assuntos
Coenzimas , Fosfato de Piridoxal , Coenzimas/metabolismo , Fosfato de Piridoxal/metabolismo , Niacinamida
13.
Biochem Soc Trans ; 50(4): 1187-1196, 2022 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-35960008

RESUMO

The nickel-pincer nucleotide (NPN) coenzyme, a substituted pyridinium mononucleotide that tri-coordinates nickel, was first identified covalently attached to a lysine residue in the LarA protein of lactate racemase. Starting from nicotinic acid adenine dinucleotide, LarB carboxylates C5 of the pyridinium ring and hydrolyzes the phosphoanhydride, LarE converts the C3 and C5 carboxylates to thiocarboxylates, and LarC incorporates nickel to form a C-Ni and two S-Ni bonds, during the biosynthesis of this cofactor. LarB uses a novel carboxylation mechanism involving the transient formation of a cysteinyl-pyridinium adduct. Depending on the source of the enzyme, LarEs either catalyze a sacrificial sulfur transfer from a cysteinyl side chain resulting in the formation of dehydroalanine or they utilize a [4Fe-4S] cluster bound by three cysteine residues to accept and transfer a non-core sulfide atom. LarC is a CTP-dependent enzyme that cytidinylylates its substrate, adds nickel, then hydrolyzes the product to release NPN and CMP. Homologs of the four lar genes are widely distributed in microorganisms, with some species containing multiple copies of larA whereas others lack this gene, consistent with the cofactor serving other functions. Several LarA-like proteins were shown to catalyze racemase or epimerase activities using 2-hydroxyacid substrates other than lactic acid. Thus, lactate racemase is the founding member of a large family of NPN-containing enzymes.


Assuntos
Lactobacillus plantarum , Níquel , Coenzimas/química , Lactobacillus plantarum/genética , Lactobacillus plantarum/metabolismo , Níquel/química , Níquel/metabolismo , Nucleotídeos/metabolismo , Enxofre/metabolismo
14.
Molecules ; 27(15)2022 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-35956883

RESUMO

The transition element molybdenum (Mo) is an essential micronutrient for plants, animals, and microorganisms, where it forms part of the active center of Mo enzymes. To gain biological activity in the cell, Mo has to be complexed by a pterin scaffold to form the molybdenum cofactor (Moco). Mo enzymes and Moco are found in all kingdoms of life, where they perform vital transformations in the metabolism of nitrogen, sulfur, and carbon compounds. In this review, I recall the history of Moco in a personal view, starting with the genetics of Moco in the 1960s and 1970s, followed by Moco biochemistry and the description of its chemical structure in the 1980s. When I review the elucidation of Moco biosynthesis in the 1990s and the early 2000s, I do it mainly for eukaryotes, as I worked with plants, human cells, and filamentous fungi. Finally, I briefly touch upon human Moco deficiency and whether there is life without Moco.


Assuntos
Metaloproteínas , Cofatores de Molibdênio , Animais , Coenzimas/química , Eucariotos/metabolismo , Humanos , Metaloproteínas/metabolismo , Molibdênio/metabolismo , Cofatores de Molibdênio/genética , Cofatores de Molibdênio/metabolismo , Plantas/metabolismo , Pterinas
15.
Nature ; 608(7924): 778-783, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35922516

RESUMO

Ferroptosis, a non-apoptotic form of cell death marked by iron-dependent lipid peroxidation1, has a key role in organ injury, degenerative disease and vulnerability of therapy-resistant cancers2. Although substantial progress has been made in understanding the molecular processes relevant to ferroptosis, additional cell-extrinsic and cell-intrinsic processes that determine cell sensitivity toward ferroptosis remain unknown. Here we show that the fully reduced forms of vitamin K-a group of naphthoquinones that includes menaquinone and phylloquinone3-confer a strong anti-ferroptotic function, in addition to the conventional function linked to blood clotting by acting as a cofactor for γ-glutamyl carboxylase. Ferroptosis suppressor protein 1 (FSP1), a NAD(P)H-ubiquinone reductase and the second mainstay of ferroptosis control after glutathione peroxidase-44,5, was found to efficiently reduce vitamin K to its hydroquinone, a potent radical-trapping antioxidant and inhibitor of (phospho)lipid peroxidation. The FSP1-mediated reduction of vitamin K was also responsible for the antidotal effect of vitamin K against warfarin poisoning. It follows that FSP1 is the enzyme mediating warfarin-resistant vitamin K reduction in the canonical vitamin K cycle6. The FSP1-dependent non-canonical vitamin K cycle can act to protect cells against detrimental lipid peroxidation and ferroptosis.


Assuntos
Ferroptose , Vitamina K , Antídotos/farmacologia , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Carbono-Carbono Ligases/metabolismo , Coenzimas/metabolismo , Ferroptose/efeitos dos fármacos , Hidroquinonas/metabolismo , Hidroquinonas/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Oxirredução , Proteína A4 de Ligação a Cálcio da Família S100/metabolismo , Vitamina K/metabolismo , Vitamina K/farmacologia , Varfarina/efeitos adversos
16.
mBio ; 13(5): e0112122, 2022 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-35993747

RESUMO

In bacteria, many essential metabolic processes are controlled by riboswitches, gene regulatory RNAs that directly bind and detect metabolites. Highly specific effector binding enables riboswitches to respond to a single biologically relevant metabolite. Cobalamin riboswitches are a potential exception because over a dozen chemically similar but functionally distinct cobalamin variants (corrinoid cofactors) exist in nature. Here, we measured cobalamin riboswitch activity in vivo using a Bacillus subtilis fluorescent reporter system and found, among 38 tested riboswitches, a subset responded to corrinoids promiscuously, while others were semiselective. Analyses of chimeric riboswitches and structural models indicate, unlike other riboswitch classes, cobalamin riboswitches indirectly differentiate among corrinoids by sensing differences in their structural conformation. This regulatory strategy aligns riboswitch-corrinoid specificity with cellular corrinoid requirements in a B. subtilis model. Thus, bacteria can employ broadly sensitive riboswitches to cope with the chemical diversity of essential metabolites. IMPORTANCE Some bacterial mRNAs contain a region called a riboswitch which controls gene expression by binding to a metabolite in the cell. Typically, riboswitches sense and respond to a limited range of cellular metabolites, often just one type. In this work, we found the cobalamin (vitamin B12) riboswitch class is an exception, capable of sensing and responding to multiple variants of B12-collectively called corrinoids. We found cobalamin riboswitches vary in corrinoid specificity with some riboswitches responding to each of the corrinoids we tested, while others responding only to a subset of corrinoids. Our results suggest the latter class of riboswitches sense intrinsic conformational differences among corrinoids in order to support the corrinoid-specific needs of the cell. These findings provide insight into how bacteria sense and respond to an exceptionally diverse, often essential set of enzyme cofactors.


Assuntos
Riboswitch , Vitamina B 12/química , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Coenzimas/metabolismo , Vitaminas
17.
Proc Natl Acad Sci U S A ; 119(36): e2207190119, 2022 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-36037354

RESUMO

Mercaptoethane sulfonate or coenzyme M (CoM) is the smallest known organic cofactor and is most commonly associated with the methane-forming step in all methanogenic archaea but is also associated with the anaerobic oxidation of methane to CO2 in anaerobic methanotrophic archaea and the oxidation of short-chain alkanes in Syntrophoarchaeum species. It has also been found in a small number of bacteria capable of the metabolism of small organics. Although many of the steps for CoM biosynthesis in methanogenic archaea have been elucidated, a complete pathway for the biosynthesis of CoM in archaea or bacteria has not been reported. Here, we present the complete CoM biosynthesis pathway in bacteria, revealing distinct chemical steps relative to CoM biosynthesis in methanogenic archaea. The existence of different pathways represents a profound instance of convergent evolution. The five-step pathway involves the addition of sulfite, the elimination of phosphate, decarboxylation, thiolation, and the reduction to affect the sequential conversion of phosphoenolpyruvate to CoM. The salient features of the pathway demonstrate reactivities for members of large aspartase/fumarase and pyridoxal 5'-phosphate-dependent enzyme families.


Assuntos
Bactérias , Coenzimas , Euryarchaeota , Mesna , Anaerobiose , Archaea/metabolismo , Bactérias/metabolismo , Coenzimas/biossíntese , Euryarchaeota/metabolismo , Mesna/metabolismo , Metano/metabolismo , Oxirredução , Fosfatos/metabolismo
18.
J Inorg Biochem ; 235: 111907, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35932756

RESUMO

Resonance Raman spectroscopy (rR) is a powerful spectroscopic probe that is widely used for studying the geometric and electronic structure of metalloproteins. In this focused review, we detail how resonance Raman spectroscopy has contributed to a greater understanding of electronic structure, geometric structure, and the reaction mechanisms of pyranopterin molybdenum enzymes. The review focuses on the enzymes sulfite oxidase (SO), dimethyl sulfoxide reductase (DMSOR), xanthine oxidase (XO), and carbon monoxide dehydrogenase. Specifically, we highlight how Mo-Ooxo, Mo-Ssulfido, Mo-Sdithiolene, and dithiolene CC vibrational modes, isotope and heavy atom perturbations, resonance enhancement, and associated Raman studies of small molecule analogs have provided detailed insight into the nature of these metalloenzyme active sites.


Assuntos
Metaloproteínas , Molibdênio , Coenzimas/química , Metaloproteínas/química , Modelos Moleculares , Molibdênio/química , Pterinas/química , Análise Espectral Raman
19.
Proc Natl Acad Sci U S A ; 119(31): e2122677119, 2022 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-35881795

RESUMO

Synthetic iron-sulfur cubanes are models for biological cofactors, which are essential to delineate oxidation states in the more complex enzymatic systems. However, a complete series of [Fe4S4]n complexes spanning all redox states accessible by 1-electron transformations of the individual iron atoms (n = 0-4+) has never been prepared, deterring the methodical comparison of structure and spectroscopic signature. Here, we demonstrate that the use of a bulky arylthiolate ligand promoting the encapsulation of alkali-metal cations in the vicinity of the cubane enables the synthesis of such a series. Characterization by EPR, 57Fe Mössbauer spectroscopy, UV-visible electronic absorption, variable-temperature X-ray diffraction analysis, and cyclic voltammetry reveals key trends for the geometry of the Fe4S4 core as well as for the Mössbauer isomer shift, which both correlate systematically with oxidation state. Furthermore, we confirm the S = 4 electronic ground state of the most reduced member of the series, [Fe4S4]0, and provide electrochemical evidence that it is accessible within 0.82 V from the [Fe4S4]2+ state, highlighting its relevance as a mimic of the nitrogenase iron protein cluster.


Assuntos
Materiais Biomiméticos , Coenzimas , Hidrocarbonetos , Ferro , Nitrogenase , Enxofre , Materiais Biomiméticos/síntese química , Materiais Biomiméticos/química , Coenzimas/síntese química , Coenzimas/química , Hidrocarbonetos/síntese química , Hidrocarbonetos/química , Ferro/química , Nitrogenase/química , Oxirredução , Enxofre/química
20.
Lab Chip ; 22(15): 2878-2885, 2022 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-35838372

RESUMO

With the rapid development of modern society, the energy crisis has become a global concern. Solar energy is a good replacement because it is green, unlimited and environment-friendly. Inspired by natural photosynthesis, artificial photosynthesis was developed to convert solar energy to chemical energy by a photocatalyst system. For better utilizing solar energy and improving the conversion efficiency, the design of photoreactors is crucial for the improvement of photocatalysis efficiency. However, most of the reported microreactors hardly satisfy the demands for low cost, easy fabrication, high transparency, being evaporation-proof, ease of scaling up, high surface-to-volume ratio, and photocatalyst immobilization. In this paper, we developed a facile method to build a fully immobilized microreactor (FIM) and a controllable partially immobilized microreactor (PIM), both of which satisfy all the demands mentioned above. In the FIM, the regeneration rate of a coenzyme (nicotinamide adenine dinucleotide, NADH) reached 82.20% in 40 min. Considering the NADH regeneration rate per unit/coating angle of photocatalysts in circular microreactors, the PIM performed much better than the FIM, proving that our partial coating method is a significant and useful improvement. Also, the bioactivity of NADH toward enzyme catalysis was demonstrated by glutamate dehydrogenase-catalyzed synthesis of L-glutamate, and the conversion of α-ketoglutarate reached 99.92%. To test the practicality of the microreactor in a real environment, we performed a test under solar light, achieving a good result of 74.92% in 60 min. Thus, this efficient and versatile microfluidic platform may have good potential for photocatalytic synthesis of versatile valuable products in the future.


Assuntos
Ácido Glutâmico , NAD , Catálise , Coenzimas , NAD/metabolismo , Fotossíntese , Regeneração
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...