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1.
Lab Chip ; 22(15): 2878-2885, 2022 Jul 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
2.
Molecules ; 27(12)2022 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-35744859

RESUMO

Molybdenum cofactor (Moco) biosynthesis requires iron, copper, and ATP. The Moco-containing enzyme sulfite oxidase catalyzes terminal oxidation in oxidative cysteine catabolism, and another Moco-containing enzyme, xanthine dehydrogenase, functions in purine catabolism. Thus, molybdenum enzymes participate in metabolic pathways that are essential for cellular detoxication and energy dynamics. Studies of the Moco biosynthetic enzymes MoaE (in the Ada2a-containing (ATAC) histone acetyltransferase complex) and MOCS2 have revealed that Moco biosynthesis and molybdenum enzymes align to regulate signaling and metabolism via control of transcription and translation. Disruption of these functions is involved in the onset of dementia and neurodegenerative disease. This review provides an overview of the roles of MoaE and MOCS2 in normal cellular processes and neurodegenerative disease, as well as directions for future research.


Assuntos
Metaloproteínas , Doenças Neurodegenerativas , Sulfito Oxidase , Coenzimas/metabolismo , Humanos , Molibdênio/metabolismo , Cofatores de Molibdênio , Sulfito Oxidase/metabolismo , Sulfurtransferases , Xantina Desidrogenase/metabolismo
3.
Methods Enzymol ; 669: 261-281, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35644174

RESUMO

B12 coenzymes are vital to healthy biological function across nature. They undergo radical chemistry in a variety of contexts, where spin-correlated radical pairs can be generated both thermally and photochemically. Owing to the unusual magnetic properties of B12 radical pairs, however, most of the reaction and spin dynamics occur on a timescale (picoseconds-nanoseconds) that cannot be resolved by most measurement techniques. Here, we describe a method that combines femtosecond transient absorption spectroscopy with magnetic field exposure, which enables the direct scrutiny of such rapid processes. This approach should provide a means by which to investigate the apparently profound effect protein environments have on the generation and reactivity of B12 radical pairs.


Assuntos
Coenzimas , Campos Magnéticos , Radicais Livres/química , Magnetismo , Análise Espectral
4.
Methods Enzymol ; 669: 283-301, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35644175

RESUMO

The chemistry of B12 coenzymes is highly sensitive to the nature of their upper axial ligand and can be further tuned by their environment. Methylcobalamin, for example, generates RPs photochemically but undergoes non-radical biochemistry when bound to its dependent enzymes. Owing to the transient nature of the reaction intermediates, it remains a challenge to investigate how their environment controls reactivity. Here, we describe how to use time-resolved electron paramagnetic spectroscopy to directly monitor the generation and evolution of transient radicals that result from the photolysis of a B12 coenzyme. This method produces evolving, spin-polarized spectra that are rich in mechanistic detail.


Assuntos
Coenzimas , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Ligantes
5.
Stem Cell Res ; 62: 102821, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35660814

RESUMO

Methylmalonic acidemia(MMA) is an autosomal recessive hereditary disease caused by methylmalonyl-CoA mutase defect or its coenzyme cobalamin metabolism defect. The mutation of the MMACHC gene leads to metabolic disorder of coenzyme cobalamin, resulting in abnormal accumulation of methylmalonic acid, and finally leads to impairment of multiple organs' functions. Here we generated an induced pluripotent stem cells (iPSCs) line named SMBCi019-A, using urine cells (UCs) derived from a 10-year-old male MMA patient who carried two heterozygous gene mutations in MMACHC c.438G > A (p.w146x) and c.609G > A (p.w203x). The generated iPSCs retained the mutations can function as a cellular model of MMA.


Assuntos
Células-Tronco Pluripotentes Induzidas , Erros Inatos do Metabolismo dos Aminoácidos , Criança , Coenzimas/genética , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Masculino , Mutação/genética , Oxirredutases/genética , Vitamina B 12/metabolismo
6.
J Biol Chem ; 298(7): 102131, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35700827

RESUMO

Sulfur-insertion reactions are essential for the biosynthesis of several cellular metabolites, including enzyme cofactors. In Lactobacillus plantarum, a sulfur-containing nickel-pincer nucleotide (NPN) cofactor is used as a coenzyme of lactic acid racemase, LarA. During NPN biosynthesis in L. plantarum, sulfur is transferred to a nicotinic acid-derived substrate by LarE, which sacrifices the sulfur atom of its single cysteinyl side chain, forming a dehydroalanine residue. Most LarE homologs contain three conserved cysteine residues that are predicted to cluster at the active site; however, the function of this cysteine cluster is unclear. In this study, we characterized LarE from Thermotoga maritima (LarETm) and show that it uses these three conserved cysteine residues to bind a [4Fe-4S] cluster that is required for sulfur transfer. Notably, we found LarETm retains all side chain sulfur atoms, in contrast to LarELp. We also demonstrate that when provided with L-cysteine and cysteine desulfurase from Escherichia coli (IscSEc), LarETm functions catalytically with IscSEc transferring sulfane sulfur atoms to LarETm. Native mass spectrometry results are consistent with a model wherein the enzyme coordinates sulfide at the nonligated iron atom of the [4Fe-4S] cluster, forming a [4Fe-5S] species, and transferring the noncore sulfide to the activated substrate. This proposed mechanism is like that of TtuA that catalyzes sulfur transfer during 2-thiouridine synthesis. In conclusion, we found that LarE sulfur insertases associated with NPN biosynthesis function either by sacrificial sulfur transfer from the protein or by transfer of a noncore sulfide bound to a [4Fe-4S] cluster.


Assuntos
Proteínas Ferro-Enxofre , Thermotoga maritima , Coenzimas/metabolismo , Cisteína/química , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Ferro-Enxofre/metabolismo , Níquel/metabolismo , Nucleotídeos/metabolismo , Sulfetos/metabolismo , Enxofre/metabolismo , Thermotoga maritima/genética , Thermotoga maritima/metabolismo
7.
Molecules ; 27(9)2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35566344

RESUMO

The role of the GMP nucleotides of the bis-molybdopterin guanine dinucleotide (bis-MGD) cofactor of the DMSO reductase family has long been a subject of discussion. The recent characterization of the bis-molybdopterin (bis-Mo-MPT) cofactor present in the E. coli YdhV protein, which differs from bis-MGD solely by the absence of the nucleotides, now enables studying the role of the nucleotides of bis-MGD and bis-MPT cofactors in Moco insertion and the activity of molybdoenzymes in direct comparison. Using the well-known E. coli TMAO reductase TorA as a model enzyme for cofactor insertion, we were able to show that the GMP nucleotides of bis-MGD are crucial for the insertion of the bis-MGD cofactor into apo-TorA.


Assuntos
Escherichia coli , Metaloproteínas , Coenzimas/metabolismo , Escherichia coli/metabolismo , Nucleotídeos de Guanina/metabolismo , Metaloproteínas/metabolismo , Molibdênio/metabolismo , Nucleotídeos/metabolismo , Pterinas
8.
Methods Enzymol ; 668: 125-136, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35589191

RESUMO

Cobamides (Cbas) are the largest coenzymes known and are used by cells in all domains of life. These molecules are characterized by a central cobalt-containing tetrapyrrole ring with two opposing axial ligands on the α and ß faces of the ring. All biologically active forms of Cbas have a 5'-deoxyadenosyl group as the upper (Coß) ligand that is covalently attached to the cobalt ion of the ring. In contrast, the lower ligand is a nucleobase of diverse chemical structure; however, nucleobases are usually derivatives of benzimidazole or purine. Phenol and p-cresol can also serve as the nucleobase, but they cannot form a coordination bond with the cobalt ion of the ring because they lack a free pair of electrons. The Cba incorporating 5,6-dimethylbenzimidazole (DMB) is known as cobalamin (Cbl), and the coenzymic form of cobalamin is known as adenosylcobalamin (AdoCbl). A common vitamer of cobalamin has a cyano group as the upper ligand. This vitamer is known as cyanocobalamin (CNCbl), which is commercially marketed as vitamin B12. Here, we describe a combination of chemical hydrolysis of cobalamin with the enzymatic dephosphorylation of the resulting α-R-3'-phosphate to yield α-R, which we enzymically convert to the pathway intermediate α-R-5'-phosphate (α-RP). The methods describe herein can be readily scaled up to generate large amounts of α-RP.


Assuntos
Fosfatos , Vitamina B 12 , Cobalto/química , Cobamidas/química , Cobamidas/metabolismo , Coenzimas , Ligantes , Ribonucleosídeos , Vitamina B 12/metabolismo , Vitaminas
9.
Methods Enzymol ; 668: 243-284, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35589195

RESUMO

Adenosylcobalamin (AdoCbl) or coenzyme B12-dependent enzymes tend to undergo mechanism-based inactivation during catalysis or inactivation in the absence of substrate. Such inactivation may be inevitable because they use a highly reactive radical for catalysis, and side reactions of radical intermediates result in the damage of the coenzyme. How do living organisms address such inactivation when enzymes are inactivated by undesirable side reactions? We discovered reactivating factors for radical B12 eliminases. They function as releasing factors for damaged cofactor(s) from enzymes and thus mediate their exchange for intact AdoCbl. Since multiple turnovers and chaperone functions were demonstrated, they were renamed "reactivases" or "reactivating chaperones." They play an essential role in coenzyme recycling as part of the activity-maintaining systems for B12 enzymes. In this chapter, we describe our investigations on reactivating chaperones, including their discovery, gene cloning, preparation, characterization, activity assays, and mechanistic studies, that have been conducted using a wide range of biochemical and structural methods that we have developed.


Assuntos
Etanolamina Amônia-Liase , Propanodiol Desidratase , Cobamidas/química , Coenzimas , Etanolamina Amônia-Liase/química , Glicerol , Hidroliases , Chaperonas Moleculares , Fosfotreonina/análogos & derivados , Propanodiol Desidratase/química , Propanodiol Desidratase/genética
10.
Methods Enzymol ; 668: 61-85, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35589202

RESUMO

Cobamides are a family of enzyme cofactors that are required by organisms in all domains of life. Over a dozen cobamides exist in nature although only cobalamin (vitamin B12), the cobamide required by humans, has been studied extensively. Cobamides are exclusively produced by a subset of prokaryotes. Importantly, the bacteria and archaea that synthesize cobamides de novo typically produce a single type of cobamide, and furthermore, organisms that use cobamides are selective for certain cobamides. Therefore, a detailed understanding of the cobamide-dependent metabolism of an organism or microbial community of interest requires experiments performed with a variety of cobamides. A notable challenge is that cobalamin is the only cobamide that is commercially available at present. In this chapter, we describe methods to extract, purify, and quantify various cobamides from bacteria for use in laboratory experiments.


Assuntos
Cobamidas , Vitamina B 12 , Bactérias/metabolismo , Cobamidas/metabolismo , Coenzimas , Humanos , Vitamina B 12/metabolismo , Vitaminas
11.
Nat Commun ; 13(1): 1879, 2022 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-35388007

RESUMO

As one of the most appealing strategies for the synthesis of nanomaterials with various architectures, emulsion-directed methods have been rarely used to control the structure of metal-organic frameworks (MOFs). Herein, we report a versatile salt-assisted nanoemulsion-guided assembly to achieve continuous architecture transition of hierarchical Zr-based MOFs. The morphology of nanoemulsion can be facilely regulated by tuning the feed ratio of a dual-surfactant and the introduced amount of compatible hydrophobic compounds, which directs the assembly of MOFs with various architectures such as bowl-like mesoporous particle, dendritic nanospheres, walnut-shaped particles, crumpled nanosheets and nanodisks. The developed dendritic nanospheres with highly open and large mesochannels is successfully used as matrix for the co-immobilization of coenzymes and corresponding enzymes to realize the in situ heterogeneous regeneration of NAD+. This strategy is expected to pave a way for exploring sophisticated hierarchical MOFs which can be competent for practical applications with bulk molecules involved.


Assuntos
Estruturas Metalorgânicas , Nanoestruturas , Coenzimas , Emulsões , Estruturas Metalorgânicas/química
12.
Virulence ; 13(1): 727-739, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35481455

RESUMO

In Staphylococcus aureus, the SaeRS two-component system is essential for the bacterium's hemolytic activity and virulence. The Newman strain of S. aureus contains a variant of SaeS sensor kinase, SaeS L18P. Previously, we showed that, in the strain Newman, SaeS L18P is degraded by the membrane-bound protease FtsH. Intriguingly, the knockout mutation of clpP, encoding the cytoplasmic protease ClpP, greatly reduces the expression of SaeS L18P. Here, we report that, in the strain Newman, the positive regulatory role of ClpP on the SaeS L18P expression is due to its destabilizing effect on FtsH and degradation of MoeA, a molybdopterin biosynthesis protein. Although the transcription of ftsH was not affected by ClpP, the expression level of FtsH was increased in the clpP mutant. The destabilizing effect appears to be indirect because ClpXP did not directly degrade FtsH in an in vitro assay. Through transposon mutagenesis, we found out that the moeA gene, encoding the molybdopterin biosynthesis protein A, suppresses the hemolytic activity of S. aureus along with the transcription and expression of SaeS L18P. In a proteolysis assay, ClpXP directly degraded MoeA, demonstrating that MoeA is a substrate of the protease. In a murine bloodstream infection model, the moeA mutant displayed reduced virulence and lower survival compared with the WT strain. Based on these results, we concluded that ClpP positively controls the expression of SaeS L18P in an FtsH and MoeA-dependent manner, and the physiological role of MoeA outweighs its suppressive effect on the SaeRS TCS during infection.


Assuntos
Infecções Estafilocócicas , Staphylococcus aureus , Animais , Coenzimas , Endopeptidases , Camundongos , Cofatores de Molibdênio , Peptídeo Hidrolases , Staphylococcus aureus/genética
13.
J Am Chem Soc ; 144(16): 7320-7326, 2022 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-35363487

RESUMO

Biocatalysis has become a powerful tool in synthetic chemistry, where enzymes are used to produce highly selective products under mild conditions. Using photocatalytically regenerated cofactors in synergistic combination with enzymes in a cascade fashion offers an efficient synthetic route to produce specific compounds. However, the combination of enzymes and photocatalysts has been limited due to the rapid degradation of the biomaterials by photogenerated reactive oxygen species, which denature and deactivate the enzymatic material. Here, we design core-shell structured porous nano-photoreactors for highly stable and recyclable photobiocatalysis under aerobic conditions. The enzymatic cofactor NAD+ from NADH can be efficiently regenerated by the photoactive organosilica core, while photogenerated active oxygen species are trapped and deactivated through the non-photoactive shell, protecting the enzymatic material. The versatility of these photocatalytic core-shell nanoreactors was demonstrated in tandem with two different enzymatic systems, glycerol dehydrogenase and glucose 1-dehydrogenase, where long-term enzyme stability was observed for the core-shell photocatalytic system.


Assuntos
Coenzimas , Glucose 1-Desidrogenase , Biocatálise
14.
Neuromuscul Disord ; 32(5): 441-444, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35487868

RESUMO

Mitochondrial dysfunction is a plausible cause of muscle fibre damage in a number of myopathies including immune-mediated necrotising myopathy. However, histopathological evidence of mitochondrial dysfunction is not often described in immune-mediated necrotising myopathy and, when present, it is often attributed to patient age. The purpose of this study was to describe features of mitochondrial dysfunction on muscle biopsy in anti-3­hydroxy-3-methylglutaryl-CoA reductase immune-mediated necrotising myopathy and explore whether these features are age-related. In this observational case control study, a statistically significant increase in the number of muscle fibres with increased lipid content (p = 0.004) and cytochrome c oxidase-negative/succinate dehydrogenase-positive fibres (p = 0.037) in anti-3­hydroxy-3-methylglutaryl-coenzyme immune-mediated necrotising myopathy was found compared to age-matched controls. Therefore, histopathological features of mitochondrial dysfunction are more frequent in anti-3­hydroxy-3-methylglutaryl-coenzyme immune-mediated necrotising myopathy than aged-matched controls and therefore, may be contributing to the pathogenesis.


Assuntos
Doenças Autoimunes , Inibidores de Hidroximetilglutaril-CoA Redutases , Doenças Musculares , Miosite , Autoanticorpos , Doenças Autoimunes/patologia , Estudos de Casos e Controles , Coenzimas , Humanos , Hidroximetilglutaril-CoA Redutases , Mitocôndrias/patologia , Músculo Esquelético/patologia , Doenças Musculares/patologia , Miosite/patologia , Necrose/patologia
15.
Commun Biol ; 5(1): 390, 2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35474238

RESUMO

Controlling the orientation of redox enzymes on electrode surfaces is essential in the development of direct electron transfer (DET)-based bioelectrocatalytic systems. The electron transfer (ET) distance varies according to the enzyme orientation when immobilized on an electrode surface, which influences the interfacial ET rate. We report control of the orientation of carbon monoxide dehydrogenase (CODH) as a model enzyme through the fusion of gold-binding peptide (gbp) at either the N- or the C-terminus, and at both termini to strengthen the binding interactions between the fusion enzyme and the gold surface. Key factors influenced by the gbp fusion site are described. Collectively, our data show that control of the CODH orientation on an electrode surface is achieved through the presence of dual tethering sites, which maintains the enzyme cofactor within a DET-available distance (<14 Å), thereby promoting DET at the enzyme-electrode interface.


Assuntos
Coenzimas , Enzimas Imobilizadas , Aldeído Oxirredutases , Coenzimas/metabolismo , DEET , Transporte de Elétrons , Enzimas Imobilizadas/metabolismo , Ouro , Complexos Multienzimáticos
16.
Sheng Wu Gong Cheng Xue Bao ; 38(2): 632-649, 2022 Feb 25.
Artigo em Chinês | MEDLINE | ID: mdl-35234387

RESUMO

The redox biosynthesis system has important applications in green biomanufacturing of chiral compounds. Formate dehydrogenase (FDH) catalyzes the oxidation of formate into carbon dioxide, which is associated with the reduction of NAD(P)+ into NAD(P)H. Due to this property, FDH is used as a crucial enzyme in the redox biosynthesis system for cofactor regeneration. Nevertheless, the application of natural FDH in industrial production is hampered by low catalytic efficiency, poor stability, and inefficient coenzyme utilization. This review summarized the structural characteristics and catalytic mechanism of FDH, as well as the advances in protein engineering of FDHs toward improved enzyme activity, catalytic efficiency, stability and coenzyme preference. The applications of using FDH as a coenzyme regeneration system for green biomanufacturing of chiral compounds were summarized.


Assuntos
Formiato Desidrogenases , NAD , Catálise , Coenzimas/metabolismo , Formiato Desidrogenases/genética , Formiato Desidrogenases/metabolismo , NAD/metabolismo , Engenharia de Proteínas
17.
Vitam Horm ; 119: 355-376, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35337626

RESUMO

Cobalamin (vitamin B12) is required for activity of the enzymes methylmalonyl-CoA mutase and methionine synthase in human cells. Inborn errors affecting cobalamin uptake or metabolism are characterized by accumulation of the substrates for these enzymes, methylmalonic acid and homocysteine, in blood and urine. Inborn errors affecting synthesis of the adenosylcobalamin coenzyme required by methylmalonyl-CoA mutase (cblA and cblB) result in isolated methylmalonic aciduria; inborn errors affecting synthesis of the methylcobalamin coenzyme required by methionine synthase (cblE and cblG) result in isolated homocystinuria. Combined methylmalonic aciduria and homocystinuria is seen in patients with impaired intestinal cobalamin absorption (intrinsic factor deficiency, Imerslund-Gräsbeck syndrome) and with defects affecting synthesis of both cobalamin coenzymes (cblC, cblD, cblF and cblJ). A series of disorders caused by pathogenic variant mutations affecting gene regulators (transcription factors) of the MMACHC gene have recently been described (HCFC1 [cblX disorder] and deficiencies of THAP11, and ZNF143 [the cblK disorder]).


Assuntos
5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase , Homocistinúria , 5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/genética , Erros Inatos do Metabolismo dos Aminoácidos , Coenzimas , Homocistinúria/genética , Humanos , Masculino , Metilmalonil-CoA Mutase/genética , Metilmalonil-CoA Mutase/metabolismo , Oxirredutases/genética , Proteínas Repressoras , Transativadores , Vitamina B 12/metabolismo
18.
Acc Chem Res ; 55(8): 1087-1096, 2022 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-35353478

RESUMO

Harnessing biocatalysts for novel abiological transformations is a longstanding goal of synthetic chemistry. Combining the merits of biocatalysis and photocatalysis allows for selective transformations fueled by visible light and offers many advantages including new reactivity, high enantioselectivity, greener syntheses, and high yields. Photoinduced electron or energy transfer enables synthetic methodologies that complement conventional two electron processes or offer orthogonal pathways for developing new reactions. Enzymes are well suited and can be tuned by directed evolution to exert control over open-shell intermediates, thereby suppressing undesirable reactions and delivering high chemo- and stereoselectivities. Within the past decade, the combination of biocatalysis and photocatalysis was mainly focused on exploiting light-regenerated cofactors to function native enzymatic activity. However, recent developments have demonstrated that the combination can unlock new-to-nature chemistry. Particularly, the discovery and application of new strategies are well poised to expand the applications of photobiocatalysis.In the past five years, our lab has been studying the combinations of photocatalysis and biocatalysis that can be applied to create new synthetic methodologies and solve challenges in synthetic organic chemistry. Our efforts have expanded the strategies for combining external photocatalysts with enzymes through the construction of a synergistic cooperative stereoconvergent reduction system consisting of photosensitized energy transfer and ene-reductase-catalyzed alkene reduction. Additionally, our efforts have also extended the capability of cofactor-dependent photoenzymatic systems to include enantioselective bimolecular radical hydroalkylations of alkenes by irradiating electron donor-acceptor complexes comprised of enzymatic redox active cofactors and unnatural substrates.In this Account, we highlight strategies developed by our group and others for combining biocatalysis and photocatalysis with the aim of introducing non-natural reactivity to enzymes. Presently, strategies applied to achieve this goal include the repurposing of natural photoenzymes, the elucidation of new photoreactivity within cofactor-dependent enzymes, the combination of external photocatalysts with enzymes, and the construction of artificial photoenzymes. By demonstrating the successful applications of these strategies for achieving selective new-to-nature transformations, we hope to spur interest in expanding the scope of photobiocatalytic systems through the use and extension of these strategies and creation of new strategies. Additionally, we hope to elucidate the intuition in synergizing the unique capabilities of biocatalysis and photocatalysis so that photobiocatalysis can be recognized as a potential solution to difficult challenges in synthetic organic chemistry.


Assuntos
Coenzimas , Oxirredutases , Alcenos/química , Biocatálise , Coenzimas/química , Luz , Oxirredutases/química
19.
Proc Natl Acad Sci U S A ; 119(14): e2110787119, 2022 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-35344442

RESUMO

SignificanceMetabolism relies on a small class of molecules (coenzymes) that serve as universal donors and acceptors of key chemical groups and electrons. Although metabolic networks crucially depend on structurally redundant coenzymes [e.g., NAD(H) and NADP(H)] associated with different enzymes, the criteria that led to the emergence of this redundancy remain poorly understood. Our combination of modeling and structural and sequence analysis indicates that coenzyme redundancy may not be essential for metabolism but could rather constitute an evolved strategy promoting efficient usage of enzymes when biochemical reactions are near equilibrium. Our work suggests that early metabolism may have operated with fewer coenzymes and that adaptation for metabolic efficiency may have driven the rise of coenzyme diversity in living systems.


Assuntos
Coenzimas , NAD , Coenzimas/metabolismo , NAD/metabolismo , NADP/metabolismo
20.
J Inorg Biochem ; 231: 111801, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35339771

RESUMO

Over 50 molybdenum enzymes in three distinct families (sulfite oxidase, xanthine oxidase, DMSO reductase) are known, and representative X-ray crystal structures are available for all families. Structural analogues that replicate the coordination about the Mo atom in the absence of surrounding protein have been synthesized and characterized. The properties of metal complexes of non-innocent dithiolene ligands and their oxidized counter parts, dithiones, are summarized. Pulsed electron paramagnetic resonance (EPR) spectroscopy of the 33S-labeled molybdenum domain of catalytically active bioengineered sulfite oxidase has clearly demonstrated delocalization of electron density from MoV to the dithiolene component of the molybdenum cofactor (Moco) of the enzyme. Moco is highly covalent and has three redox active components: the Mo atom; the dithiolene; and the pterin. In principle, Moco can have a total of eight redox states, making it one of the most redox rich cofactors in biology. The {Moco}n formalism, developed here, gives the total number of electrons (n) associated with a particular redox state of Moco. This flexible notation eliminates the need to assign a specific oxidation state to each of the three components of Moco and allows for internal redistribution of electrons among the components upon substrate binding, changes in the surrounding network of hydrogen bonds, conformational changes, and catalysis. An unexpected result is that sulfite oxidase (an oxotransferase) is predicted to utilize the {Moco}4-6 electron distributions during catalysis, whereas xanthine oxidase (a hydroxylase) is predicted to utilize the {Moco}6-8 electron distributions during catalysis.


Assuntos
Metaloproteínas , Sulfito Oxidase , Coenzimas/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Humanos , Molibdênio/química , Pteridinas , Sulfito Oxidase/química
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