Enzymatic halogenation: enzyme mining, mechanisms, and implementation in reaction cascades

Dachwitz, Steffen; Widmann, Christiane; Frese, Marcel; Niemann, Hartmut H.; Sewald, Norbert

doi:10.1039/9781788017008-00001

Cited by 14 publications

(18 citation statements)

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“…Nowadays, computational methods are the easiest way to detect potential halogenating proteins for example using genome-mining tools like antiSMASH or Blastp [ 24 , 44 ]. These genome-mining methods are very useful for the detection of enzymes present in biosynthetic gene clusters (mainly for FDHs) [ 45 , 46 , 47 ].…”

Section: Halogenation Enzymesmentioning

confidence: 99%

“…For iodine, the thymol-blue (thymolsulfonphtalein) assay can be used to characterize specificity as well as the o -dianisidine assay in native protein gel directly [ 49 , 50 ]. Because of the higher specificity of FDHs, enzymatic characterization of this family of enzyme has to be done with the specific substrate of each protein [ 30 , 47 ].…”

Section: Halogenation Enzymesmentioning

confidence: 99%

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Halogenation in Fungi: What Do We Know and What Remains to Be Discovered?

et al. 2022

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In nature, living organisms produce a wide variety of specialized metabolites to perform many biological functions. Among these specialized metabolites, some carry halogen atoms on their structure, which can modify their chemical characteristics. Research into this type of molecule has focused on how organisms incorporate these atoms into specialized metabolites. Several families of enzymes have been described gathering metalloenzymes, flavoproteins, or S-adenosyl-L-methionine (SAM) enzymes that can incorporate these atoms into different types of chemical structures. However, even though the first halogenation enzyme was discovered in a fungus, this clade is still lagging behind other clades such as bacteria, where many enzymes have been discovered. This review will therefore focus on all halogenation enzymes that have been described in fungi and their associated metabolites by searching for proteins available in databases, but also by using all the available fungal genomes. In the second part of the review, the chemical diversity of halogenated molecules found in fungi will be discussed. This will allow the highlighting of halogenation mechanisms that are still unknown today, therefore, highlighting potentially new unknown halogenation enzymes.

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Section: Halogenation Enzymesmentioning

confidence: 99%

Section: Halogenation Enzymesmentioning

confidence: 99%

Halogenation in Fungi: What Do We Know and What Remains to Be Discovered?

et al. 2022

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“…Both enzymes have the characteristic flavin binding module GxGxxG, the conserved lysine residue (K85 and K81, respectively), and the WxWxIP motif suppressing monooxygenase activity [33]. The reduced flavin (FADH 2 ) reacts with molecular oxygen, forming the FAD(C4a)-peroxide, which in turn reacts with halide ions under HOX formation [2,5,28,29]. In contrast, heme-or vanadium-dependent haloperoxidases require hydrogen peroxide and release the halogenating species hypohalous acid HOX into the medium, which leads to unselective halogenation [2,65,66].…”

Section: Determination Of Halogenation Activity and Substrate Scopementioning

confidence: 99%

“…Nature has evolved enzymatic halogenation, making use of different cofactors [2]. The enzymatic halogenation by flavin-dependent halogenases may overcome the drawbacks of chemical halogenation, since it often is highly regioselective and only requires a halide salt as a halogen source, water, oxygen, and reduced flavin-adenosinedinucleotide (FADH 2 ) as a cofactor [1,[3][4][5][6]. In general, flavin-dependent halogenases belong to the superfamily of flavin-dependent monooxygenases, which are able to activate molecular oxygen by using reduced flavin (FADH 2 ) [7], thus allowing diverse reactions, such as hydroxylation, epoxidation, and Baeyer-Villiger oxidation [8].…”

Section: Introductionmentioning

confidence: 99%

Two Novel, Flavin-Dependent Halogenases from the Bacterial Consortia of Botryococcus braunii Catalyze Mono- and Dibromination

et al. 2021

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Halogen substituents often lead to a profound effect on the biological activity of organic compounds. Flavin-dependent halogenases offer the possibility of regioselective halogenation at non-activated carbon atoms, while employing only halide salts and molecular oxygen. However, low enzyme activity, instability, and narrow substrate scope compromise the use of enzymatic halogenation as an economical and environmentally friendly process. To overcome these drawbacks, it is of tremendous interest to identify novel halogenases with high enzymatic activity and novel substrate scopes. Previously, Neubauer et al. developed a new hidden Markov model (pHMM) based on the PFAM tryptophan halogenase model, and identified 254 complete and partial putative flavin-dependent halogenase genes in eleven metagenomic data sets. In the present study, the pHMM was used to screen the bacterial associates of the Botryococcus braunii consortia (PRJEB21978), leading to the identification of several putative, flavin-dependent halogenase genes. Two of these new halogenase genes were found in one gene cluster of the Botryococcus braunii symbiont Sphingomonas sp. In vitro activity tests revealed that both heterologously expressed enzymes are active flavin-dependent halogenases able to halogenate indole and indole derivatives, as well as phenol derivatives, while preferring bromination over chlorination. Interestingly, SpH1 catalyses only monohalogenation, while SpH2 can catalyse both mono- and dihalogenation for some substrates.

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“…Besides addressing the indole C 2 , the regioselective enzymatic halogenation at C5, C6, or C7 using FAD-dependent tryptophan halogenases opens a broad area of Pd-catalysed late-stage diversifications [53][54][55]. It has been proven that Pd-catalysed cross-couplings are very versatile tools for selective and bio-orthogonal modifications of haloindoles, halotryptophans and halotryptophan-containing peptides as well as natural products [56][57][58][59][60][61][62][63][64][65][66][67][68][69][70].…”

Section: Introductionmentioning

confidence: 99%

Peptide stapling by late-stage Suzuki–Miyaura cross-coupling

Gruß

Feiner

Mseya

et al. 2022

Beilstein J. Org. Chem.

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The development of peptide stapling techniques to stabilise α-helical secondary structure motifs of peptides led to the design of modulators of protein–protein interactions, which had been considered undruggable for a long time. We disclose a novel approach towards peptide stapling utilising macrocyclisation by late-stage Suzuki–Miyaura cross-coupling of bromotryptophan-containing peptides of the catenin-binding domain of axin. Optimisation of the linker length in order to find a compromise between both sufficient linker rigidity and flexibility resulted in a peptide with an increased α-helicity and enhanced binding affinity to its native binding partner β-catenin. An increased proteolytic stability against proteinase K has been demonstrated.

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Enzymatic halogenation: enzyme mining, mechanisms, and implementation in reaction cascades

Cited by 14 publications

References 0 publications

Halogenation in Fungi: What Do We Know and What Remains to Be Discovered?

Halogenation in Fungi: What Do We Know and What Remains to Be Discovered?

Two Novel, Flavin-Dependent Halogenases from the Bacterial Consortia of Botryococcus braunii Catalyze Mono- and Dibromination

Peptide stapling by late-stage Suzuki–Miyaura cross-coupling

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