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Cambridge, United Kingdom

Law B.J.C.,University of Manchester | Struck A.-W.,University of Manchester | Bennett M.R.,University of Manchester | Wilkinson B.,John Innes Center | And 2 more authors.
Chemical Science | Year: 2015

The methylation of natural products by S-adenosyl methionine (AdoMet, also known as SAM)-dependent methyltransferase enzymes is a common tailoring step in many biosynthetic pathways. The introduction of methyl substituents can affect the biological and physicochemical properties of the secondary metabolites produced. Recently it has become apparent that some AdoMet-dependent methyltransferases exhibit promiscuity and will accept AdoMet analogues enabling the transfer of alternative alkyl groups. In this study we have characterised a methyltransferase, RapM, which is involved in the biosynthesis of the potent immunosuppressive agent rapamycin. We have shown that recombinant RapM regioselectively methylates the C16 hydroxyl group of desmethyl rapamycin precursors in vitro and is promiscuous in accepting alternative co-factors in addition to AdoMet. A coupled enzyme system was developed, including a mutant human enzyme methionine adenosyl transferase (MAT), along with RapM, which was used to prepare alkylated rapamycin derivatives (rapalogs) with alternative ethyl and allyl ether groups, derived from simple S-ethyl or S-allyl methionine analogues. There are two other methyltransferases RapI and RapQ which provide methyl substituents of rapamycin. Consequently, using the enzymatic approach described here, it should be possible to generate a diverse array of alkylated rapalogs, with altered properties, that would be difficult to obtain by traditional synthetic approaches. © The Royal Society of Chemistry 2015. Source


Netzker T.,Leibniz Institute for Natural Product Research and Infection Biology | Netzker T.,Friedrich - Schiller University of Jena | Schroeckh V.,Leibniz Institute for Natural Product Research and Infection Biology | Gregory M.A.,Isomerase Therapeutics Ltd. | And 7 more authors.
Applied and Environmental Microbiology | Year: 2016

Streptomyces iranensis HM 35 is an alternative rapamycin producer to Streptomyces rapamycinicus. Targeted genetic modification of rapamycin-producing actinomycetes is a powerful tool for the directed production of rapamycin derivatives, and it has also revealed some key features of the molecular biology of rapamycin formation in S. rapamycinicus. The approach depends upon efficient conjugational plasmid transfer from Escherichia coli to Streptomyces, and the failure of this step has frustrated its application to Streptomyces iranensis HM 35. Here, by systematically optimizing the process of conjugational plasmid transfer, including screening of various media, and by defining optimal temperatures and concentrations of antibiotics and Ca2+ ions in the conjugation media, we have achieved exconjugant formation for each of a series of gene deletions in S. iranensis HM 35. Among them were rapK, which generates the starter unit for rapamycin biosynthesis, and hutF, encoding a histidine catabolizing enzyme. The protocol that we have developed may allow efficient generation of targeted gene knockout mutants of Streptomyces species that are genetically difficult to manipulate. © 2016, American Society for Microbiology. All Rights Reserved. Source


Hansson M.,NeuroVive Pharmaceutical | Hansson M.,Lund University | Moss S.,Isomerase Therapeutics Ltd. | Bobardt M.,Scripps Research Institute | And 13 more authors.
Chemistry and Biology | Year: 2015

Inhibition of host-encoded targets, such as the cyclophilins, provides an opportunity to generate potent high barrier to resistance antivirals for the treatment of a broad range of viral diseases. However, many host-targeted agents are natural products, which can be difficult to optimize using synthetic chemistry alone. We describe the orthogonal combination of bioengineering and semisynthetic chemistry to optimize the drug-like properties of sanglifehrin A, a known cyclophilin inhibitor of mixed nonribosomal peptide/polyketide origin, to generate the drug candidate NVP018 (formerly BC556). NVP018 is a potent inhibitor of hepatitis B virus, hepatitis C virus (HCV), and HIV-1 replication, shows minimal inhibition of major drug transporters, and has a high barrier to generation of both HCV and HIV-1 resistance. Hansson etal. describe the generation and preclinical analysis of a bacterial natural product with activity as a host-targeted antiviral drug. This was generated by a combination of biosynthetic engineering and semisynthetic chemistry. © 2015 Elsevier Ltd. Source


Novoa E.M.,Barcelona Institute for Research in Biomedicine | Novoa E.M.,Massachusetts Institute of Technology | Camacho N.,Barcelona Institute for Research in Biomedicine | Tor A.,Barcelona Institute for Research in Biomedicine | And 19 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2014

Malaria remains a major global health problem. Emerging resistance to existing antimalarial drugs drives the search for new antimalarials, and protein translation is a promising pathway to target. Here we explore the potential of the aminoacyl-tRNA synthetase (ARS) family as a source of antimalarial drug targets. First, a battery of known and novel ARS inhibitors was tested against Plasmodium falciparum cultures, and their activities were compared. Borrelidin, a natural inhibitor of threonyl-tRNA synthetase (ThrRS), stands out for its potent antimalarial effect. However, it also inhibits human ThrRS and is highly toxic to human cells. To circumvent this problem, we tested a library of bioengineered and semisynthetic borrelidin analogs for their antimalarial activity and toxicity. We found that some analogs effectively lose their toxicity against human cells while retaining a potent antiparasitic activity both in vitro and in vivo and cleared malaria from Plasmodium yoelii-infected mice, resulting in 100%mice survival rates. Our work identifies borrelidin analogs as potent, selective, and unexplored scaffolds that efficiently clear malaria both in vitro and in vivo. © 2014, National Academy of Sciences. All rights reserved. Source


Hansson M.J.,NeuroVive Pharmaceutical | Hansson M.J.,Lund University | Moss S.J.,Isomerase Therapeutics Ltd. | Moss S.J.,Biotica Technology Ltd. | And 18 more authors.
Chemistry and Biology | Year: 2015

Inhibition of host-encoded targets, such as the cyclophilins, provides an opportunity to generate potent high barrier to resistance antivirals for the treatment of a broad range of viral diseases. However, many host-targeted agents are natural products, which can be difficult to optimize using synthetic chemistry alone. We describe the orthogonal combination of bioengineering and semisynthetic chemistry to optimize the drug-like properties of sanglifehrin A, a known cyclophilin inhibitor of mixed nonribosomal peptide/polyketide origin, to generate the drug candidate NVP018 (formerly BC556). NVP018 is a potent inhibitor of hepatitis B virus, hepatitis C virus (HCV), and HIV-1 replication, shows minimal inhibition of major drug transporters, and has a high barrier to generation of both HCV and HIV-1 resistance. © 2015 Elsevier Ltd. Source

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