@misc{Leimkuehler2020, author = {Leimk{\"u}hler, Silke}, title = {The biosynthesis of the molybdenum cofactors in Escherichia coli}, series = {Environmental microbiology}, volume = {22}, journal = {Environmental microbiology}, number = {6}, publisher = {Wiley}, address = {Hoboken}, issn = {1462-2912}, doi = {10.1111/1462-2920.15003}, pages = {2007 -- 2026}, year = {2020}, abstract = {The biosynthesis of the molybdenum cofactor (Moco) is highly conserved among all kingdoms of life. In all molybdoenzymes containing Moco, the molybdenum atom is coordinated to a dithiolene group present in the pterin-based 6-alkyl side chain of molybdopterin (MPT). In general, the biosynthesis of Moco can be divided into four steps in in bacteria: (i) the starting point is the formation of the cyclic pyranopterin monophosphate (cPMP) from 5 '-GTP, (ii) in the second step the two sulfur atoms are inserted into cPMP leading to the formation of MPT, (iii) in the third step the molybdenum atom is inserted into MPT to form Moco and (iv) in the fourth step bis-Mo-MPT is formed and an additional modification of Moco is possible with the attachment of a nucleotide (CMP or GMP) to the phosphate group of MPT, forming the dinucleotide variants of Moco. This review presents an update on the well-characterized Moco biosynthesis in the model organism Escherichia coli including novel discoveries from the recent years.}, language = {en} } @misc{LeimkuehlerBuehningBeilschmidt2017, author = {Leimk{\"u}hler, Silke and B{\"u}hning, Martin and Beilschmidt, Lena}, title = {Shared sulfur mobilization routes for tRNA thiolation and molybdenum cofactor biosynthesis in prokaryotes and eukaryotes}, series = {Biomolecules}, volume = {7}, journal = {Biomolecules}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {2218-273X}, doi = {10.3390/biom7010005}, pages = {20}, year = {2017}, abstract = {Modifications of transfer RNA (tRNA) have been shown to play critical roles in the biogenesis, metabolism, structural stability and function of RNA molecules, and the specific modifications of nucleobases with sulfur atoms in tRNA are present in pro- and eukaryotes. Here, especially the thiomodifications xm(5)s(2)U at the wobble position 34 in tRNAs for Lys, Gln and Glu, were suggested to have an important role during the translation process by ensuring accurate deciphering of the genetic code and by stabilization of the tRNA structure. The trafficking and delivery of sulfur nucleosides is a complex process carried out by sulfur relay systems involving numerous proteins, which not only deliver sulfur to the specific tRNAs but also to other sulfur-containing molecules including iron-sulfur clusters, thiamin, biotin, lipoic acid and molybdopterin (MPT). Among the biosynthesis of these sulfur-containing molecules, the biosynthesis of the molybdenum cofactor (Moco) and the synthesis of thio-modified tRNAs in particular show a surprising link by sharing protein components for sulfur mobilization in pro- and eukaryotes.}, language = {en} } @misc{RomaoCoelhoSantosSilvaetal.2017, author = {Romao, Maria Joao and Coelho, Catarina and Santos-Silva, Teresa and Foti, Alessandro and Terao, Mineko and Garattini, Enrico and Leimk{\"u}hler, Silke}, title = {Structural basis for the role of mammalian aldehyde oxidases in the metabolism of drugs and xenobiotics}, series = {Current Opinion in Chemical Biology}, volume = {37}, journal = {Current Opinion in Chemical Biology}, publisher = {Elsevier}, address = {Oxford}, issn = {1367-5931}, doi = {10.1016/j.cbpa.2017.01.005}, pages = {39 -- 47}, year = {2017}, abstract = {Aldehyde oxidases (AOXs) are molybdo-flavoenzymes characterized by broad substrate specificity, oxidizing aromatic/aliphatic aldehydes into the corresponding carboxylic acids and hydroxylating various heteroaromatic rings. Mammals are characterized by a complement of species specific AOX isoenzymes, that varies from one in humans (AOX1) to four in rodents (AOX1, AOX2, AOX3 and AOX4). The physiological function of mammalian AOX isoenzymes is unknown, although human AOX1 is an emerging enzyme in phase-I drug metabolism. Indeed, the number of therapeutic molecules under development which act as AOX substrates is increasing. The recent crystallization and structure determination of human AOX1 as well as mouse AOX3 has brought new insights into the mechanisms underlying substrate/inhibitor binding as well as the catalytic activity of this class of enzymes.}, language = {en} } @misc{MotaCoelhoLeimkuehleretal.2018, author = {Mota, Cristiano and Coelho, Catarina and Leimk{\"u}hler, Silke and Garattini, Enrico and Terao, Mineko and Santos-Silva, Teresa and Romao, Maria Joao}, title = {Critical overview on the structure and metabolism of human aldehyde oxidase and its role in pharmacokinetics}, series = {Coordination chemistry reviews}, volume = {368}, journal = {Coordination chemistry reviews}, publisher = {Elsevier}, address = {Lausanne}, issn = {0010-8545}, doi = {10.1016/j.ccr.2018.04.006}, pages = {35 -- 59}, year = {2018}, abstract = {Aldehyde oxidases are molybdenum and flavin dependent enzymes characterized by a very wide substrate specificity and performing diverse reactions that include oxidations (e.g., aldehydes and azaheterocycles), hydrolysis of amide bonds, and reductions (e.g., nitro, S-oxides and N-oxides). Oxidation reactions and amide hydrolysis occur at the molybdenum site while the reductions are proposed to occur at the flavin site. AOX activity affects the metabolism of different drugs and xenobiotics, some of which designed to resist other liver metabolizing enzymes (e.g., cytochrome P450 monooxygenase isoenzymes), raising its importance in drug development. This work consists of a comprehensive overview on aldehyde oxidases, concerning the genetic evolution of AOX, its diversity among the human population, the crystal structures available, the known catalytic reactions and the consequences in pre-clinical pharmacokinetic and pharmacodynamic studies. Analysis of the different animal models generally used for pre-clinical trials and comparison between the human (hAOX1), mouse homologs as well as the related xanthine oxidase (XOR) are extensively considered. The data reviewed also include a systematic analysis of representative classes of molecules that are hAOX1 substrates as well as of typical and well characterized hAOX1 inhibitors. The considerations made on the basis of a structural and functional analysis are correlated with reported kinetic and metabolic data for typical classes of drugs, searching for potential structural determinants that may dictate substrate and/or inhibitor specificities.}, language = {en} } @misc{ZupokIobbiNivolMejeanetal.2019, author = {Zupok, Arkadiusz and Iobbi-Nivol, Chantal and Mejean, Vincent and Leimk{\"u}hler, Silke}, title = {The regulation of Moco biosynthesis and molybdoenzyme gene expression by molybdenum and iron in bacteria}, series = {Metallomics : integrated biometal science}, volume = {11}, journal = {Metallomics : integrated biometal science}, number = {10}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1756-5901}, doi = {10.1039/c9mt00186g}, pages = {1602 -- 1624}, year = {2019}, abstract = {Bacterial molybdoenzymes are key enzymes involved in the global sulphur, nitrogen and carbon cycles. These enzymes require the insertion of the molybdenum cofactor (Moco) into their active sites and are able to catalyse a large range of redox-reactions. Escherichia coli harbours nineteen different molybdoenzymes that require a tight regulation of their synthesis according to substrate availability, oxygen availability and the cellular concentration of molybdenum and iron. The synthesis and assembly of active molybdoenzymes are regulated at the level of transcription of the structural genes and of translation in addition to the genes involved in Moco biosynthesis. The action of global transcriptional regulators like FNR, NarXL/QP, Fur and ArcA and their roles on the expression of these genes is described in detail. In this review we focus on what is known about the molybdenum- and iron-dependent regulation of molybdoenzyme and Moco biosynthesis genes in the model organism E. coli. The gene regulation in E. coli is compared to two other well studied model organisms Rhodobacter capsulatus and Shewanella oneidensis.}, language = {en} } @misc{Leimkuehler2017, author = {Leimk{\"u}hler, Silke}, title = {Shared function and moonlighting proteins in molybdenum cofactor biosynthesis}, series = {Biological chemistry}, volume = {398}, journal = {Biological chemistry}, publisher = {De Gruyter}, address = {Berlin}, issn = {1431-6730}, doi = {10.1515/hsz-2017-0110}, pages = {1009 -- 1026}, year = {2017}, abstract = {The biosynthesis of the molybdenum cofactor (Moco) is a highly conserved pathway in bacteria, archaea and eukaryotes. The molybdenum atom in Moco-containing enzymes is coordinated to the dithiolene group of a tricyclic pyranopterin monophosphate cofactor. The biosynthesis of Moco can be divided into three conserved steps, with a fourth present only in bacteria and archaea: (1) formation of cyclic pyranopterin monophosphate, (2) formation of molybdopterin (MPT), (3) insertion of molybdenum into MPT to form Mo-MPT, and (4) additional modification of Mo-MPT in bacteria with the attachment of a GMP or CMP nucleotide, forming the dinucleotide variants of Moco. While the proteins involved in the catalytic reaction of each step of Moco biosynthesis are highly conserved among the Phyla, a surprising link to other cellular pathways has been identified by recent discoveries. In particular, the pathways for FeS cluster assembly and thio-modifications of tRNA are connected to Moco biosynthesis by sharing the same protein components. Further, proteins involved in Moco biosynthesis are not only shared with other pathways, but additionally have moonlighting roles. This review gives an overview of Moco biosynthesis in bacteria and humans and highlights the shared function and moonlighting roles of the participating proteins.}, language = {en} } @misc{LeimkuehlerIobbiNivol2016, author = {Leimk{\"u}hler, Silke and Iobbi-Nivol, Chantal}, title = {Bacterial molybdoenzymes: old enzymes for new purposes}, series = {FEMS microbiology reviews}, volume = {40}, journal = {FEMS microbiology reviews}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0168-6445}, doi = {10.1093/femsre/fuv043}, pages = {1 -- 18}, year = {2016}, abstract = {Molybdoenzymes are widespread in eukaryotic and prokaryotic organisms where they play crucial functions in detoxification reactions in the metabolism of humans and bacteria, in nitrate assimilation in plants and in anaerobic respiration in bacteria. To be fully active, these enzymes require complex molybdenum-containing cofactors, which are inserted into the apoenzymes after folding. For almost all the bacterial molybdoenzymes, molybdenum cofactor insertion requires the involvement of specific chaperones. In this review, an overview on the molybdenum cofactor biosynthetic pathway is given together with the role of specific chaperones dedicated for molybdenum cofactor insertion and maturation. Many bacteria are involved in geochemical cycles on earth and therefore have an environmental impact. The roles of molybdoenzymes in bioremediation and for environmental applications are presented.This review gives an overview of the diverse mechanisms leading to the insertion of the different forms of the molybdenum cofactor into the respective target enzymes and summarizes the roles of different molybdoenzymes in the environment.This review gives an overview of the diverse mechanisms leading to the insertion of the different forms of the molybdenum cofactor into the respective target enzymes and summarizes the roles of different molybdoenzymes in the environment.}, language = {en} } @misc{TeraoRomaoLeimkuehleretal.2016, author = {Terao, Mineko and Romao, Maria Joao and Leimk{\"u}hler, Silke and Bolis, Marco and Fratelli, Maddalena and Coelho, Catarina and Santos-Silva, Teresa and Garattini, Enrico}, title = {Structure and function of mammalian aldehyde oxidases}, series = {Archives of toxicology : official journal of EUROTOX}, volume = {90}, journal = {Archives of toxicology : official journal of EUROTOX}, publisher = {Springer}, address = {Heidelberg}, issn = {0340-5761}, doi = {10.1007/s00204-016-1683-1}, pages = {753 -- 780}, year = {2016}, abstract = {Mammalian aldehyde oxidases (AOXs; EC1.2.3.1) are a group of conserved proteins belonging to the family of molybdo-flavoenzymes along with the structurally related xanthine dehydrogenase enzyme. AOXs are characterized by broad substrate specificity, oxidizing not only aromatic and aliphatic aldehydes into the corresponding carboxylic acids, but also hydroxylating a series of heteroaromatic rings. The number of AOX isoenzymes expressed in different vertebrate species is variable. The two extremes are represented by humans, which express a single enzyme (AOX1) in many organs and mice or rats which are characterized by tissue-specific expression of four isoforms (AOX1, AOX2, AOX3, and AOX4). In vertebrates each AOX isoenzyme is the product of a distinct gene consisting of 35 highly conserved exons. The extant species-specific complement of AOX isoenzymes is the result of a complex evolutionary process consisting of a first phase characterized by a series of asynchronous gene duplications and a second phase where the pseudogenization and gene deletion events prevail. In the last few years remarkable advances in the elucidation of the structural characteristics and the catalytic mechanisms of mammalian AOXs have been made thanks to the successful crystallization of human AOX1 and mouse AOX3. Much less is known about the physiological function and physiological substrates of human AOX1 and other mammalian AOX isoenzymes, although the importance of these proteins in xenobiotic metabolism is fairly well established and their relevance in drug development is increasing. This review article provides an overview and a discussion of the current knowledge on mammalian AOX.}, language = {en} } @misc{MendelLeimkuehler2015, author = {Mendel, Ralf R. and Leimk{\"u}hler, Silke}, title = {The biosynthesis of the molybdenum cofactors}, series = {Journal of biological inorganic chemistry}, volume = {20}, journal = {Journal of biological inorganic chemistry}, number = {2}, publisher = {Springer}, address = {New York}, issn = {0949-8257}, doi = {10.1007/s00775-014-1173-y}, pages = {337 -- 347}, year = {2015}, abstract = {The biosynthesis of the molybdenum cofactors (Moco) is an ancient, ubiquitous, and highly conserved pathway leading to the biochemical activation of molybdenum. Moco is the essential component of a group of redox enzymes, which are diverse in terms of their phylogenetic distribution and their architectures, both at the overall level and in their catalytic geometry. A wide variety of transformations are catalyzed by these enzymes at carbon, sulfur and nitrogen atoms, which include the transfer of an oxo group or two electrons to or from the substrate. More than 50 molybdoenzymes were identified to date. In all molybdoenzymes except nitrogenase, molybdenum is coordinated to a dithiolene group on the 6-alkyl side chain of a pterin called molybdopterin (MPT). The biosynthesis of Moco can be divided into three general steps, with a fourth one present only in bacteria and archaea: (1) formation of the cyclic pyranopterin monophosphate, (2) formation of MPT, (3) insertion of molybdenum into molybdopterin to form Moco, and (4) additional modification of Moco in bacteria with the attachment of a nucleotide to the phosphate group of MPT, forming the dinucleotide variant of Moco. This review will focus on the biosynthesis of Moco in bacteria, humans and plants.}, language = {en} } @misc{YokoyamaLeimkuehler2015, author = {Yokoyama, Kenichi and Leimk{\"u}hler, Silke}, title = {The role of FeS clusters for molybdenum cofactor biosynthesis and molybdoenzymes in bacteria}, series = {Biochimica et biophysica acta : Molecular cell research}, volume = {1853}, journal = {Biochimica et biophysica acta : Molecular cell research}, number = {6}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0167-4889}, doi = {10.1016/j.bbamcr.2014.09.021}, pages = {1335 -- 1349}, year = {2015}, abstract = {The biosynthesis of the molybdenum cofactor (Moco) has been intensively studied, in addition to its insertion into molybdoenzymes. In particular, a link between the assembly of molybdoenzymes and the biosynthesis of FeS clusters has been identified in the recent years: 1) the synthesis of the first intermediate in Moco biosynthesis requires an FeS-cluster containing protein, 2) the sulfurtransferase for the dithiolene group in Moco is also involved in the synthesis of FeS clusters, thiamin and thiolated tRNAs, 3) the addition of a sulfido-ligand to the molybdenum atom in the active site additionally involves a sulfurtransferase, and 4) most molybdoenzymes in bacteria require FeS clusters as redox active cofactors. In this review we will focus on the biosynthesis of the molybdenum cofactor in bacteria, its modification and insertion into molybdoenzymes, with an emphasis to its link to FeS cluster biosynthesis and sulfur transfer. (C) 2014 Elsevier B.V. All rights reserved.}, language = {en} }