66844-06-2Relevant academic research and scientific papers
Switching the Mechanism of NADH Photooxidation by Supramolecular Interactions
Mengele, Alexander K.,Weixler, Dominik,Chettri, Avinash,Maurer, Maite,Huber, Fabian Lukas,Seibold, Gerd M.,Dietzek, Benjamin,Eikmanns, Bernhard J.,Rau, Sven
supporting information, p. 16840 - 16845 (2021/10/25)
A series of three Ru(II) polypyridine complexes was investigated for the selective photocatalytic oxidation of NAD(P)H to NAD(P)+ in water. A combination of (time-resolved) spectroscopic studies and photocatalysis experiments revealed that ligand design can be used to control the mechanism of the photooxidation: For prototypical Ru(II) complexes a 1O2 pathway was found. Rudppz ([(tbbpy)2Ru(dppz)]Cl2, tbbpy=4,4'-di-tert-butyl-2,2'-bipyridine, dppz=dipyrido[3,2-a:2′,3′-c]phenazine), instead, initiated the cofactor oxidation by electron transfer from NAD(P)H enabled by supramolecular binding between substrate and catalyst. Expulsion of the photoproduct NAD(P)+ from the supramolecular binding site in Rudppz allowed very efficient turnover. Therefore, Rudppz permits repetitive selective assembly and oxidative conversion of reduced naturally occurring nicotinamides by recognizing the redox state of the cofactor under formation of H2O2 as additional product. This photocatalytic process can fuel discontinuous photobiocatalysis.
Fluorescent half-sandwich phosphine-sulfonate iridium(III) and ruthenium(II) complexes as potential lysosome-targeted anticancer agents
Du, Qing,Yang, Yuliang,Guo, Lihua,Tian, Meng,Ge, Xingxing,Tian, Zhenzhen,Zhao, Liping,Xu, Zhishan,Li, Juanjuan,Liu, Zhe
, p. 821 - 830 (2018/11/23)
The synthesis, characterization and biological activity of neutral fluorescent Ir(III) and Ru(II) half-sandwich organometallic complexes containing phosphine-sulfonate ligands are reported. X-ray crystal structure of complexes 1–3, 10 and 11 exhibits the expected half-sandwich “three-legged piano-stool” pseudo-octahedral geometry. Spectroscopic properties study displays that these complexes show rich fluorescence properties. With the exception of 9, 10 and 11 toward A549 human lung cancer cells and 10 towards HeLa human cervical cancer cells, each complex shows promising cytotoxicity toward HeLa and A549 cells line with IC50 values in the range of 3.6–53.1 μM, and 6.5–34.5 μM, respectively. Hydrolysis, DNA cleavage and depolarization of the mitochondrial membrane potential (MMP) appear not to be the main mechanism of action. However, these complexes are able to covert NADH to NAD+ via the transfer hydrogenation. Mechanism studies by flow cytometry display that the complexes exert their anticancer efficacy by inducing apoptosis, perturbing the cell cycle and increasing the intracellular ROS level. Furthermore, fluorescence property of these complexes provides a tool to investigate the microscopic mechanism by confocal microscopy. Notably, the typical Ir(III) complex 3 can specially localize to lysosome and damage it. In addition, complex 3 enters into HeLa cells mainly through energy-dependent pathway.
Organometallic ruthenium and iridium phosphorus complexes: Synthesis, cellular imaging, organelle targeting and anticancer applications
Li, JuanJuan,Tian, Zhenzhen,Zhang, Shumiao,Xu, Zhishan,Mao, Xudong,Zhou, Yumin,Liu, Zhe
, (2019/02/20)
The use of metal complexes containing phosphorus ligands as anticancer agents has not been well studied. In this work, eight novel half-sandwich IrIII and RuII compounds with P^P-chelating ligands have been synthesized and fully characterized, and alongside two crystal structures were reported. All eight complexes displayed highly potent antiproliferative activity, up to nine times more potent than the clinical anticancer drug cisplatin towards A549 lung cancer cells. Complex Ir1, which has a simpler structure and highly potent antiproliferative activity, was selected to investigate in further mechanistic studies. No hydrolysis and nucleobase binding occurred for complex Ir1. In order to elucidate subcellular localization, the self-luminescence of the complex Ir1 was utilized. Ir1 can specifically target lysosomes and facilitate excessive production of reactive oxygen species, resulting in lysosomal membrane permeabilization in A549 cells. Release of cathepsin B and changes in the mitochondria membrane potential also contributed to the observed cytotoxicity of Ir1, which demonstrated an anticancer action mechanism that was different from that of cisplatin. The favorable results from biological and chemical research demonstrated that these types of complexes hold significant theranostic potential.
Toward Automated Enzymatic Glycan Synthesis in a Compartmented Flow Microreactor System
Heinzler, Raphael,Fisch?der, Thomas,Elling, Lothar,Franzreb, Matthias
supporting information, p. 4506 - 4516 (2019/08/20)
Immobilized microfluidic enzyme reactors (IMER) are of particular interest for automation of enzyme cascade reactions. Within an IMER, substrates are converted by paralleled immobilized enzyme modules and intermediate products are transported for further conversion by subsequent enzyme modules. By optimizing substrate conversion in the spatially separated enzyme modules purification of intermediate products is not necessary, thus shortening process time and increasing space-time yields. The IMER enables the development of efficient enzyme cascades by combining compatible enzymatic reactions in different arrangements under optimal conditions and the possibility of a cost-benefit analysis prior to scale-up. These features are of special interest for automation of enzymatic glycan synthesis. We here demonstrate a compartmented flow microreactor system using six magnetic enzyme beads (MEBs) for the synthesis of the non-sulfated human natural killer cell-1 (HNK-1) glycan epitope. MEBs are assembled to build compartmented enzyme modules, consisting of enzyme cascades for the synthesis of uridine 5′- diphospho-α- d-galactose (UDP-Gal) and uridine 5′-diphospho-α-d-glucuronic acid (UDP-GlcA), the donor substrates for the Leloir glycosyltransferases β4-galactosyltransferase and β3-glucuronosyltransferase, respectively. Glycan synthesis was realized in an automated microreactor system by a cascade of individual enzyme module compartments each performing under optimal conditions. The products were analyzed inline by an MS-system connected to the microreactor. The high synthesis yield of 96% for the non-sulfated HNK-1 glycan epitope indicates the excellent performance of the automated enzyme module cascade. Furthermore, combinations of other MEBs for nucleotide sugars synthesis with MEBs of glycosyltransferases have the potential for a fully automated and programmed glycan synthesis in a compartmented flow microreactor system. (Figure presented.).
Ferrocene-appended iridium(III) Complexes: Configuration regulation, anticancer application, and mechanism research
Ge, Xingxing,Chen, Shujiao,Liu, Xicheng,Wang, Qinghui,Gao, Lijun,Zhao, Chengfeng,Zhang, Lei,Shao, Mingxiao,Yuan, Xiang-Ai,Tian, Laijin,Liu, Zhe
supporting information, p. 14175 - 14184 (2019/10/16)
A series of ferrocene-appended half-sandwiched iridium(III) phenylpyridine complexes have been designed and synthesized. These complexes show better anticancer activity than cisplatin widely used in clinic under the same conditions. Meanwhile, complexes could effectively inhibit cell migration and colony formation. Complexes could interact with protein and transport through serum protein, effectively catalyzing the oxidation of nicotinamide-adenine dinucleotid and inducing the accumulation of reactive oxygen species (ROS, 1O2), which confirmed the anticancer mechanism of oxidation. Furthermore, laser scanning confocal detection indicates that these complexes can enter cells followed by a non-energy-dependent cellular uptake mechanism, effectively accumulating in the lysosome (Pearson's colocalization coefficient: ～0.90), leading to lysosome damage, and reducing the mitochondrial membrane potential (MMP). Taken together, ferrocene-appended iridium(III) complexes possess the prospect of becoming a new multifunctional therapeutic platform, including lysosome-targeted imaging and anticancer drugs.
MftD Catalyzes the Formation of a Biologically Active Redox Center in the Biosynthesis of the Ribosomally Synthesized and Post-translationally Modified Redox Cofactor Mycofactocin
Ayikpoe, Richard S.,Latham, John A.
, (2019/09/06)
Mycofactocin (MFT) is a putative ribosomally synthesized and post-translationally modified (RiPP) redox cofactor. The biosynthesis of MFT is encoded by the gene cluster mftABCDEF. While processing of the precursor peptide by MftB, MftC, and MftE has been shown to result in the formation of the small molecule 3-amino-5-[(p-hydroxyphenyl)methyl]-4,4-dimethyl-2-pyrrolidinone (AHDP), no activity has been shown for the putative dehydrogenase MftD and the putative glycosyltransferase MftF. In addition, evidence demonstrating that MFT is a redox cofactor has only been limited to the requirement of mft genes for ethanol assimilation in Mycobacterium smegmatis mc2155. Here, we demonstrate that MftD catalyzes the oxidative deamination of AHDP, forming an α-keto moiety on the resulting molecule, which we call pre-mycofactocin (PMFT). We characterize PMFT by 1D and 2D NMR spectroscopy techniques and by high-resolution mass spectrometry data to solve its structure. We further characterized PMFT by cyclic voltammetry and found its midpoint potential to be ～255 mV. Lastly, we demonstrate that PMFT is a biologically active redox cofactor that oxidizes NADH bound by M. smegmatis carveol dehydrogenase (MsCDH) and can be used by MsCDH in the oxidation of carveol. These data demonstrate for the first time that PMFT functions as a biologically active redox mediator and provides the most direct evidence to date that MFT is a RiPP-derived redox cofactor.
Emissive Synthetic Cofactors: Enzymatic Interconversions of tzA Analogues of ATP, NAD+, NADH, NADP+, and NADPH
Hallé, Fran?ois,Fin, Andrea,Rovira, Alexander R.,Tor, Yitzhak
supporting information, p. 1087 - 1090 (2017/12/28)
A series of enzymatic transformations, which generate visibly emissive isofunctional cofactors based on an isothiazolo[4,3-d]pyrimidine analogue of adenosine (tzA), was developed. Nicotinamide adenylyl transferase condenses nicotinamide mononucleotide and tzATP to yield NtzAD+, which can be enzymatically phosphorylated by NAD+ kinase and ATP or tzATP to the corresponding NtzADP+. The latter can be engaged in NADP-specific coupled enzymatic transformations involving conversion to NtzADPH by glucose-6-phosphate dehydrogenase and reoxidation to NtzADP+ by glutathione reductase. The NtzADP+/NtzADPH cycle can be monitored in real time by fluorescence spectroscopy.
Half-sandwich Iridium(III) Benzimidazole-Appended Imidazolium-Based N-heterocyclic Carbene Complexes and Antitumor Application
Han, Yali,Liu, Xicheng,Tian, Zhenzhen,Ge, Xingxing,Li, Juanjuan,Gao, Min,Li, Yanru,Liu, Yi,Liu, Zhe
supporting information, p. 3697 - 3705 (2018/11/03)
A series of half-sandwich iridium(III) benzimidazole-appended imidazolium-based N-heterocyclic carbene (NHC) antitumor complexes [(η5-Cpx)Ir(C^N)Cl]Cl, where Cpx is pentamethylcyclopentadienyl (Cp*) or its biphenyl derivative (Cpxbiph) and C^N is a NHC chelating ligand, were successfully synthesized and characterized. The IrIII complexes showed potential antitumor activity against A549 cells, at most three times more potent than cis-platin under the same conditions. Complexes could bind to BSA by a static quenching mode, catalyzing the change of NADH to NAD+ and inducing the production of reactive oxygen species (maximum turnover number, 9.8), which play an important role in regulating cell apoptosis. Confocal microscopy showed that the complexes could specifically target lysosomes in cells with a Pearson's co-localization coefficient 0.76 and 0.72 after 1 h and 6 h, respectively, followed an energy-dependent cellular uptake mechanism and damaged the integrity of lysosomes. At the same time, complexes caused a marked loss of mitochondrial membrane potential.
Photobiocatalytic alcohol oxidation using LED light sources
Rauch,Schmidt,Arends,Oppelt,Kara,Hollmann
supporting information, p. 376 - 379 (2017/08/14)
The photocatalytic oxidation of NADH using a flavin photocatalyst and a simple blue LED light source is reported. This in situ NAD+ regeneration system can be used to promote biocatalytic, enantioselective oxidation reactions. Compared to the traditional use of white light bulbs this method enables very significant reductions in energy consumption and CO2 emission.
Novel half-sandwich iridium(iii) imino-pyridyl complexes showing remarkable: In vitro anticancer activity
Li, Juanjuan,Guo, Lihua,Tian, Zhenzhen,Tian, Meng,Zhang, Shumiao,Xu, Ke,Qian, Yuchuan,Liu, Zhe
supporting information, p. 15520 - 15534 (2017/11/22)
Seven novel half-sandwich IrIII cyclopentadienyl complexes, [(η5-Cpx)Ir(N^N)Cl]PF6, have been prepared and characterized, where Cpx is Cp? or the biphenyl derivative Cpxbiph (C5Me4C6H4C6H5), and the N^N-chelating ligands are imino-pyridyl Schiff-bases. The X-ray crystal structures of complexes 2A, 2B, and 3A have been determined. Excitingly, most of the complexes show potent antiproliferative activity towards A549 and HeLa cancer cells, except for Cp? complex 1A towards HeLa cells. Cpxbiph complex 2B displayed the highest potency, about 19 and 6 times more active than the clinically used drug cisplatin toward A549 and HeLa cells, respectively. These complexes undergo hydrolysis, and the kinetics data have been calculated. DNA binding has been studied by interaction with nucleobases 9-ethylguanine and 9-methyladenine, cleavage of plasmid DNA, and interaction with ctDNA. Interaction with DNA does not appear to be the major mechanism of action. Protein binding (bovine serum albumin, BSA) has been established by UV-Vis, fluorescence and synchronous spectroscopic studies. The stability of complex 2B in the presence of GSH was evaluated. The complexes catalytically convert coenzyme NADH to NAD+via hydride transfer. Cpxbiph complexes 2B and 4B induce cell apoptosis and arrest cell cycles at the S and G2/M phases towards A549 cancer cells and increase the reactive oxygen species dramatically, which appear to contribute to the remarkable anticancer activity.
