Flavin-dependent biocatalysts in synthesis

Dockrey, Summer A. Baker; Narayan, Alison R. H.

doi:10.1016/j.tet.2019.01.008

Cited by 35 publications

(34 citation statements)

References 45 publications

(61 reference statements)

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“…As flavin-dependent monooxygenases are attractive for many applications ( 3 , 10 , 11 , 12 , 14 , 54 ), identification of residues important for catalysis provides basic knowledge for future rational design in enzyme engineering. As HadA is useful for many applications including detoxification and biodetection ( 9 ), the structural basis reported here should be useful for improving HadA for industrial applications.…”

Section: Discussionmentioning

confidence: 99%

Structural insights into a flavin-dependent dehalogenase HadA explain catalysis and substrate inhibition via quadruple π-stacking

Pimviriyakul

Jaruwat

Chitnumsub

et al. 2021

Journal of Biological Chemistry

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HadA is a flavin-dependent monooxygenase catalyzing hydroxylation plus dehalogenation/denitration, which is useful for biodetoxification and biodetection. In this study, the X-ray structure of wild-type HadA (HadA WT ) co-complexed with reduced FAD (FADH – ) and 4-nitrophenol (4NP) (HadA WT −FADH – −4NP) was solved at 2.3-Å resolution, providing the first full package (with flavin and substrate bound) structure of a monooxygenase of this type. Residues Arg101, Gln158, Arg161, Thr193, Asp254, Arg233, and Arg439 constitute a flavin-binding pocket, whereas the 4NP-binding pocket contains the aromatic side chain of Phe206, which provides π-π stacking and also is a part of the hydrophobic pocket formed by Phe155, Phe286, Thr449, and Leu457. Based on site-directed mutagenesis and stopped-flow experiments, Thr193, Asp254, and His290 are important for C4a-hydroperoxyflavin formation with His290, also serving as a catalytic base for hydroxylation. We also identified a novel structural motif of quadruple π-stacking (π-π-π-π) provided by two 4NP and two Phe441 from two subunits. This motif promotes 4NP binding in a nonproductive dead-end complex, which prevents C4a-hydroperoxy-FAD formation when HadA is premixed with aromatic substrates. We also solved the structure of the HadA Phe441Val −FADH – −4NP complex at 2.3-Å resolution. Although 4NP can still bind to this variant, the quadruple π-stacking motif was disrupted. All HadA Phe441 variants lack substrate inhibition behavior, confirming that quadruple π-stacking is a main cause of dead-end complex formation. Moreover, the activities of these HadA Phe441 variants were improved by ⁓20%, suggesting that insights gained from the flavin-dependent monooxygenases illustrated here should be useful for future improvement of HadA’s biocatalytic applications.

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Section: Discussionmentioning

confidence: 99%

Structural insights into a flavin-dependent dehalogenase HadA explain catalysis and substrate inhibition via quadruple π-stacking

Pimviriyakul

Jaruwat

Chitnumsub

et al. 2021

Journal of Biological Chemistry

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“…Encouraged by the identification of such highly effective guanidino-flavins for bacterial inactivation, we were interested to see if the trend would be similar for coronaviruses, specifically, the SARS-CoV-2 surrogate, murine hepatitis virus A59 strain (MHV-A59). 4 > It has already been demonstrated that riboflavin can effectively inactivate both enveloped and non-enveloped viruses in blood products using UV light, [20][21][22][23][24] but much lower efficacy was observed using visible light (0.4x10 5 lx, 0.5-2 h) against hepatitis B virus (HBV). 77,78 In order to evaluate possible applicability towards topical infection treatment and pathogen-inactivating surface coatings or textiles, [79][80][81][82] we used an in vitro S3 for 17Cl-1 cytotoxicity data).…”

Section: Photodynamic Inactivation Of Murine Hepatitis Virus (Mhv-a59)mentioning

confidence: 99%

“…1,2 Due to their rich redox chemistry and ability to mediate a wide range of both oxidative and reductive organic transformations, flavin-containing enzymes are prominently used as biocatalysts. 3,4 Flavins are also involved in the regulation of photochemical pathways due to strong blue light absorption, which results in the generation of highly oxidising excited states that can elicit biological signalling events or responses. [5][6][7][8] This photoexcitation process has been exploited in a number of photocatalytic applications, whereby modification of the flavin chromophore can enable the formation of high potential oxidative and reductive intermediates to afford useful synthetic methodology.…”

Section: Introductionmentioning

confidence: 99%

Tuning Riboflavin Derivatives For Photodynamic Inactivation of Pathogens

Fruk

Crocker

Lee

et al. 2021

Preprint

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The development of effective pathogen reduction strategies is required due to the rise in antibiotic-resistant bacteria and zoonotic viral pandemics. Photodynamic inactivation (PDI) of bacteria and viruses is a potent reduction strategy that bypasses typical resistance mechanisms. Naturally occurring riboflavin has been widely used in PDI applications due to efficient light-induced reactive oxygen species (ROS) release. By rational design of its core structure to alter (photo)physical properties, we obtained derivatives capable of outperforming riboflavin’s visible light-iinduced PDI against E. coli and a SARS-CoV-2 surrogate, revealing functional group dependency for each pathogen. Bacterial PDI was influenced mainly by guanidino substitution, whereas viral PDI increased through bromination of the flavin. These observations were related to enhanced uptake and ROS-specific nucleic acid cleavage mechanisms. Trends in the derivatives’ toxicity towards human fibroblast cells were also investigated to assess viable therapeutic derivatives and help guide further design of PDI agents to combat pathogenic organisms.

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“…Using the example of oxyfunctionalisation enzymes such as cytochrome P450 monooxygenases (P450s), [51,52] unspecific peroxygenases (UPOs), [53,54] flavin‐dependent monooxygenases, [55,56] Rieske dioxygenases, [57,58] and αKGDs, [59,60] this perspective complements recent cutting‐edge biocatalysis review articles [2,14,16,17,61,62] in order to aid the transition towards sustainable chemistry by wide‐spread combinations of chemo‐ and biocatalysis [63–66] . Many of the here presented examples do not involve commercial enzyme kits yet, but rather self‐generated mutant libraries.…”

Section: Introductionmentioning

confidence: 96%

Enzyme Kits to Facilitate the Integration of Biocatalysis into Organic Chemistry – First Aid for Synthetic Chemists

2022

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First Aid Kits are collections of the most important medical equipment required for quick medical assistance. Similarly, enzyme kits can provide a proficient, ready-and easy-to-use collection of biocatalysts that can be applied with high reproducibility. In this article, we illustrate how kits of oxyfunctionalisation enzymes could operate as synthetic 'First Aid' for chemists working on complex natural product total synthesis in an early-or late-stage fashion, as well as in lead diversification in drug discovery processes. We reason that enzyme kits could catalyse the integration of biocatalysis into (synthetic) organic chemistry and describe how we envision their future application.

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Flavin-dependent biocatalysts in synthesis

Cited by 35 publications

References 45 publications

Structural insights into a flavin-dependent dehalogenase HadA explain catalysis and substrate inhibition via quadruple π-stacking

Structural insights into a flavin-dependent dehalogenase HadA explain catalysis and substrate inhibition via quadruple π-stacking

Tuning Riboflavin Derivatives For Photodynamic Inactivation of Pathogens

Enzyme Kits to Facilitate the Integration of Biocatalysis into Organic Chemistry – First Aid for Synthetic Chemists

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