Pleuromutilin Explained

Pleuromutilin and its derivatives are antibacterial drugs that inhibit protein synthesis in bacteria by binding to the peptidyl transferase component of the 50S subunit of ribosomes.^{[1] [2]}

This class of antibiotics includes the licensed drugs lefamulin (for systemic use in humans), retapamulin (approved for topical use in humans), valnemulin and tiamulin (approved for use in animals) and the investigational drug azamulin.

History

Pleuromutilin was discovered as an antibiotic in 1951.^{[3] [4]} It is derived from the fungi Omphalina mutila (formerly Pleurotus mutilus) and Clitopilus passeckerianus (formerly Pleurotus passeckerianus),^[3] and has also been found in Drosophila subatrata, Clitopilus scyphoides, and some other Clitopilus species.^[5]

Total synthesis

The total synthesis of pleuromutilin has been reported.^{[6] [7] [8] [9]}

Biosynthesis

Pleuromutilin belongs to the class of secondary metabolites known as terpenes, which are produced in fungi through the mevalonate pathway (MEP pathway).^[10] Its synthetic bottleneck lays on the production of the precursor GGPP and the following formation of the tricyclic structure, which is catalyzed by Pl-cyc, a bifunctional diterpene synthase (DTS). This Cyclase shows a new class II DTS activity, catalyzes a ring contraction and the formation of a 5-6-bicyclic ring structure. Specifically, DTS shows two catalytic distinguishable domains: On the one hand it has at the N-terminal region a class II DTS domain, which catalyzes a cascade cyclization, resulting in a decalin core. Subsequently, variable 1,2-proton and methyl shifts occur to translocate the carbocation towards one of the two interconnecting C-atoms and this intermediate induces a base-catalyzed ring contraction. Therefore, class II DTS promotes in general a ring contraction during the cyclisation of GGPP. On the other hand, at the C-terminal end it has a class I DTS domain, which catalyzes a conjugated dephosphorylation, generating the 8-membered cyclic core, followed by a 1,5-proton shift and a stereospecific hydroxylation to obtain premutilin.^[11] Additionally, three cytochrome P450s (Pl-p450-1, Pl-p450-2 and Pl-p450-3) are involved in the final steps of the pleuromutilin biosynthetic pathway.^[12] The P450-1 and P450-2 are essential for hydroxylation of two ring structures regarding the premutilin skeleton, oxidating specifically at position C-11 and C-3, respectively. The short-chain dehydrogenase/reductase enzyme (Pl-sdr) has a regiospecific activity and converts the 3-hydroxy group to a ketone, forming the intermediate mutilin. Acetyltransferase (Pl-atf) catalyzes the transfer of acetyl group to 14-OH of mutilin. Finally, Pl-p450-3 hydroxylates the α-methyl group of the acetyl side chain generating pleuromutilin.^[13]

Further reading

• Long KS, Hansen LH, Jakobsen L, Vester B . Interaction of pleuromutilin derivatives with the ribosomal peptidyl transferase center . Antimicrobial Agents and Chemotherapy . 50 . 4 . 1458–62 . April 2006 . 16569865 . 1426994 . 10.1128/AAC.50.4.1458-1462.2006 . free . 8900413 . free .
• Lolk L, Pøhlsgaard J, Jepsen AS, Hansen LH, Nielsen H, Steffansen SI, Sparving L, Nielsen AB, Vester B, Nielsen P . 6 . A click chemistry approach to pleuromutilin conjugates with nucleosides or acyclic nucleoside derivatives and their binding to the bacterial ribosome . Journal of Medicinal Chemistry . 51 . 16 . 4957–67 . August 2008 . 18680270 . 10.1021/jm800261u . 931146 .

Notes and References

1. Book: Maffioli . Sonia Ilaria . 2013 . A chemist's survey of different antibiotic classes . Gualerzi . Claudio O. . Brandi . Letizia . Fabbretti . Attilio . Pon . Cynthia L. . Antibiotics: Targets, Mechanisms and Resistance . Wiley-VCH . 1–22 . 10.1002/9783527659685.ch1 . 978-3-527-65968-5 . 11479628.
2. Eyal Z, Matzov D, Krupkin M, Paukner S, Riedl R, Rozenberg H, Zimmerman E, Bashan A, Yonath A . A novel pleuromutilin antibacterial compound, its binding mode and selectivity mechanism . Sci Rep . 6(39004) . Dec 2016 . 39004 . 27958389 . 10.1038/srep39004 . 5154188 . 2016NatSR...639004E . free .
3. Kavanagh F, Hervey A, Robbins WJ. September 1951 . Antibiotic substances from basidiomycetes: VIII. Pleurotus multilus (Fr.) Sacc. and Pleurotus passeckerianus Pilat.. Proceedings of the National Academy of Sciences of the United States of America. 37 . 9. 570–574. 10.1073/pnas.37.9.570. 16589015. 1063423. 1951PNAS...37..570K . free .
4. Novak R, Shlaes DM . The pleuromutilin antibiotics: a new class for human use . Current Opinion in Investigational Drugs . 11 . 2 . 182–91 . February 2010 . 20112168 . 41588014 .
5. Kilaru S, Collins CM, Hartley AJ, Bailey AM, Foster GD . Establishing molecular tools for genetic manipulation of the pleuromutilin-producing fungus Clitopilus passeckerianus . Applied and Environmental Microbiology . 75 . 22 . 7196–204 . November 2009 . 19767458 . 2786515 . 10.1128/AEM.01151-09 . 2009ApEnM..75.7196K . free . 22127410 . free .
6. Gibbons . E. Grant . 1982 . Total synthesis of (±)-pleuromutilin . Journal of the American Chemical Society . 104 . 6 . 1767–1769 . 10.1021/ja00370a067 . 102155530.
7. Boeckman . Robert K. . Springer . Dane M. . Alessi . Thomas R. . 1989 . Synthetic studies directed toward naturally occurring cyclooctanoids. 2. A stereocontrolled assembly of (±)-pleuromutilin via a remarkable sterically demanding oxy-Cope rearrangement . Journal of the American Chemical Society . 111 . 21 . 8284–8286 . 10.1021/ja00203a043 . 96627402.
8. Fazakerley NJ, Helm MD, Procter DJ . Total synthesis of (+)-pleuromutilin . Chemistry: A European Journal . 19 . 21 . 6718–23 . May 2013 . 23589420 . 10.1002/chem.201300968 . 46105984 .
9. Murphy SK, Zeng M, Herzon SB . A modular and enantioselective synthesis of the pleuromutilin antibiotics . Science . 356 . 6341 . 956–959 . June 2017 . 28572392 . 7001679 . 10.1126/science.aan0003 . 2017Sci...356..956M . free . 206658420 . free .
10. Lange BM, Rujan T, Martin W, Croteau R . Isoprenoid biosynthesis: the evolution of two ancient and distinct pathways across genomes . Proceedings of the National Academy of Sciences of the United States of America . 97 . 24 . 13172–7 . November 2000 . 11078528 . 27197 . 10.1073/pnas.240454797 . 2000PNAS...9713172M . free .
11. Lin HC, Hewage RT, Lu YC, Chooi YH . Biosynthesis of bioactive natural products from Basidiomycota . Organic & Biomolecular Chemistry . 17 . 5 . 1027–1036 . January 2019 . 30608100 . 10.1039/C8OB02774A . 58661785 .
12. Alberti F, Khairudin K, Venegas ER, Davies JA, Hayes PM, Willis CL, Bailey AM, Foster GD . 6 . Heterologous expression reveals the biosynthesis of the antibiotic pleuromutilin and generates bioactive semi-synthetic derivatives . Nature Communications . 8 . 1 . 1831 . November 2017 . 29184068 . 5705593 . 10.1038/s41467-017-01659-1 . 2017NatCo...8.1831A .
13. Bailey AM, Alberti F, Kilaru S, Collins CM, de Mattos-Shipley K, Hartley AJ, Hayes P, Griffin A, Lazarus CM, Cox RJ, Willis CL, O'Dwyer K, Spence DW, Foster GD . 6 . Identification and manipulation of the pleuromutilin gene cluster from Clitopilus passeckerianus for increased rapid antibiotic production . Scientific Reports . 6 . 1 . 25202 . May 2016 . 27143514 . 4855138 . 10.1038/srep25202 . 2016NatSR...625202B .