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Chapman NC, Rutledge PJ. Isopenicillin N Synthase: Crystallographic Studies. Chembiochem 2021; 22:1687-1705. [PMID: 33415840 DOI: 10.1002/cbic.202000743] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 01/01/2021] [Indexed: 02/02/2023]
Abstract
Isopenicillin N synthase (IPNS) is a non-heme iron oxidase (NHIO) that catalyses the cyclisation of tripeptide δ-(l-α-aminoadipoyl)-l-cysteinyl-d-valine (ACV) to bicyclic isopenicillin N (IPN). Over the last 25 years, crystallography has shed considerable light on the mechanism of IPNS catalysis. The first crystal structure, for apo-IPNS with Mn bound in place of Fe at the active site, reported in 1995, was also the first structure for a member of the wider NHIO family. This was followed by the anaerobic enzyme-substrate complex IPNS-Fe-ACV (1997), this complex plus nitric oxide as a surrogate for co-substrate dioxygen (1997), and an enzyme product complex (1999). Since then, crystallography has been used to probe many aspects of the IPNS reaction mechanism, by crystallising the protein with a diversity of substrate analogues and triggering the oxidative reaction by using elevated oxygen pressures to force the gaseous co-substrate throughout protein crystals and maximise synchronicity of turnover in crystallo. In this way, X-ray structures have been elucidated for a range of complexes closely related to and/or directly derived from key intermediates in the catalytic cycle, thereby answering numerous mechanistic questions that had arisen from solution-phase experiments, and posing many new ones. The results of these crystallographic studies have, in turn, informed computational experiments that have brought further insight. These combined crystallographic and computational investigations augment and extend the results of earlier spectroscopic analyses and solution phase studies of IPNS turnover, to enrich our understanding of this important protein and the wider NHIO enzyme family.
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Affiliation(s)
- Nicole C Chapman
- School of Chemistry, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Peter J Rutledge
- School of Chemistry, The University of Sydney, Sydney, New South Wales, 2006, Australia
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Yadav V, Siegler MA, Goldberg DP. Temperature-Dependent Reactivity of a Non-heme Fe III(OH)(SR) Complex: Relevance to Isopenicillin N Synthase. J Am Chem Soc 2021; 143:46-52. [PMID: 33356198 DOI: 10.1021/jacs.0c09688] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Non-heme iron complexes with cis-FeIII(OH)(SAr/OAr) coordination were isolated and examined for their reactivity with a tertiary carbon radical. The sulfur-ligated complex shows a temperature dependence on •OH versus ArS• transfer, whereas the oxygen-ligated complex does not. These results provide the first working model for C-S bond formation in isopenicillin N synthase and indicate that kinetic control may be a key factor in the selectivity of non-heme iron "rebound" processes.
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Affiliation(s)
- Vishal Yadav
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Maxime A Siegler
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - David P Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
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Rabe P, Kamps JJAG, Schofield CJ, Lohans CT. Roles of 2-oxoglutarate oxygenases and isopenicillin N synthase in β-lactam biosynthesis. Nat Prod Rep 2018; 35:735-756. [PMID: 29808887 PMCID: PMC6097109 DOI: 10.1039/c8np00002f] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Indexed: 01/01/2023]
Abstract
Covering: up to 2017 2-Oxoglutarate (2OG) dependent oxygenases and the homologous oxidase isopenicillin N synthase (IPNS) play crucial roles in the biosynthesis of β-lactam ring containing natural products. IPNS catalyses formation of the bicyclic penicillin nucleus from a tripeptide. 2OG oxygenases catalyse reactions that diversify the chemistry of β-lactams formed by both IPNS and non-oxidative enzymes. Reactions catalysed by the 2OG oxygenases of β-lactam biosynthesis not only involve their typical hydroxylation reactions, but also desaturation, epimerisation, rearrangement, and ring-forming reactions. Some of the enzymes involved in β-lactam biosynthesis exhibit remarkable substrate and product selectivities. We review the roles of 2OG oxygenases and IPNS in β-lactam biosynthesis, highlighting opportunities for application of knowledge of their roles, structures, and mechanisms.
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Affiliation(s)
- Patrick Rabe
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Jos J A G Kamps
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Christopher J Schofield
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Christopher T Lohans
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
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McNeill LA, Brown TJN, Sami M, Clifton IJ, Burzlaff NI, Claridge TDW, Adlington RM, Baldwin JE, Rutledge PJ, Schofield CJ. Terminally Truncated Isopenicillin N Synthase Generates a Dithioester Product: Evidence for a Thioaldehyde Intermediate during Catalysis and a New Mode of Reaction for Non-Heme Iron Oxidases. Chemistry 2017; 23:12815-12824. [PMID: 28703303 PMCID: PMC5637899 DOI: 10.1002/chem.201701592] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Indexed: 11/25/2022]
Abstract
Isopenicillin N synthase (IPNS) catalyses the four-electron oxidation of a tripeptide, l-δ-(α-aminoadipoyl)-l-cysteinyl-d-valine (ACV), to give isopenicillin N (IPN), the first-formed β-lactam in penicillin and cephalosporin biosynthesis. IPNS catalysis is dependent upon an iron(II) cofactor and oxygen as a co-substrate. In the absence of substrate, the carbonyl oxygen of the side-chain amide of the penultimate residue, Gln330, co-ordinates to the active-site metal iron. Substrate binding ablates the interaction between Gln330 and the metal, triggering rearrangement of seven C-terminal residues, which move to take up a conformation that extends the final α-helix and encloses ACV in the active site. Mutagenesis studies are reported, which probe the role of the C-terminal and other aspects of the substrate binding pocket in IPNS. The hydrophobic nature of amino acid side-chains around the ACV binding pocket is important in catalysis. Deletion of seven C-terminal residues exposes the active site and leads to formation of a new type of thiol oxidation product. The isolated product is shown by LC-MS and NMR analyses to be the ene-thiol tautomer of a dithioester, made up from two molecules of ACV linked between the thiol sulfur of one tripeptide and the oxidised cysteinyl β-carbon of the other. A mechanism for its formation is proposed, supported by an X-ray crystal structure, which shows the substrate ACV bound at the active site, its cysteinyl β-carbon exposed to attack by a second molecule of substrate, adjacent. Formation of this product constitutes a new mode of reaction for IPNS and non-heme iron oxidases in general.
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Affiliation(s)
- Luke A. McNeill
- Oxford Centre for Molecular Sciences and the Department of ChemistryChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
- Present Address: Oxford Nanopore Technologies, Oxford Science ParkOX4 4GAUK
| | - Toby J. N. Brown
- Oxford Centre for Molecular Sciences and the Department of ChemistryChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
- Present Address: The Brattle GroupLevel 15 5 Martin PlaceSydney, NSW2000Australia
| | - Malkit Sami
- Oxford Centre for Molecular Sciences and the Department of ChemistryChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
- Present Address: Immunocore Limited101 Park Drive, Milton ParkAbingdonOX14 4RYUK
| | - Ian J. Clifton
- Oxford Centre for Molecular Sciences and the Department of ChemistryChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Nicolai I. Burzlaff
- Department of Chemistry and PharmacyUniversity of Erlangen-NurembergEgerlandstraße 191058ErlangenGermany
| | - Timothy D. W. Claridge
- Oxford Centre for Molecular Sciences and the Department of ChemistryChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Robert M. Adlington
- Oxford Centre for Molecular Sciences and the Department of ChemistryChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Jack E. Baldwin
- Oxford Centre for Molecular Sciences and the Department of ChemistryChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | | | - Christopher J. Schofield
- Oxford Centre for Molecular Sciences and the Department of ChemistryChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
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Clifton IJ, Ge W, Adlington RM, Baldwin JE, Rutledge PJ. The crystal structure of an isopenicillin N synthase complex with an ethereal substrate analogue reveals water in the oxygen binding site. FEBS Lett 2013; 587:2705-9. [DOI: 10.1016/j.febslet.2013.07.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 07/04/2013] [Accepted: 07/04/2013] [Indexed: 10/26/2022]
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Daruzzaman A, Clifton IJ, Adlington RM, Baldwin JE, Rutledge PJ. The Interaction of Isopenicillin N Synthase with Homologated Substrate Analogues δ-(L-α-Aminoadipoyl)-L-homocysteinyl-D-Xaa Characterised by Protein Crystallography. Chembiochem 2013; 14:599-606. [DOI: 10.1002/cbic.201200728] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Indexed: 11/11/2022]
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Daruzzaman A, Clifton IJ, Adlington RM, Baldwin JE, Rutledge PJ. The crystal structure of isopenicillin N synthase with a dipeptide substrate analogue. Arch Biochem Biophys 2013; 530:48-53. [DOI: 10.1016/j.abb.2012.12.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 12/07/2012] [Accepted: 12/09/2012] [Indexed: 11/29/2022]
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Hamed RB, Gomez-Castellanos JR, Henry L, Ducho C, McDonough MA, Schofield CJ. The enzymes of β-lactam biosynthesis. Nat Prod Rep 2013; 30:21-107. [DOI: 10.1039/c2np20065a] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Dungan VJ, Wong SM, Barry SM, Rutledge PJ. l-Proline-derived ligands to mimic the ‘2-His-1-carboxylate’ triad of the non-haem iron oxidase active site. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.02.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Barry SM, Mueller-Bunz H, Rutledge PJ. Investigating the oxidation of alkenes by non-heme iron enzyme mimics. Org Biomol Chem 2012; 10:7372-81. [DOI: 10.1039/c2ob25834j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Clifton IJ, Ge W, Adlington RM, Baldwin JE, Rutledge PJ. The crystal structure of isopenicillin N synthase with δ-(l-α-aminoadipoyl)-l-cysteinyl-d-methionine reveals thioether coordination to iron. Arch Biochem Biophys 2011; 516:103-7. [DOI: 10.1016/j.abb.2011.09.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 09/28/2011] [Accepted: 09/30/2011] [Indexed: 12/01/2022]
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Ab initio structural modeling of and experimental validation for Chlamydia trachomatis protein CT296 reveal structural similarity to Fe(II) 2-oxoglutarate-dependent enzymes. J Bacteriol 2011; 193:6517-28. [PMID: 21965559 DOI: 10.1128/jb.05488-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Chlamydia trachomatis is a medically important pathogen that encodes a relatively high percentage of proteins with unknown function. The three-dimensional structure of a protein can be very informative regarding the protein's functional characteristics; however, determining protein structures experimentally can be very challenging. Computational methods that model protein structures with sufficient accuracy to facilitate functional studies have had notable successes. To evaluate the accuracy and potential impact of computational protein structure modeling of hypothetical proteins encoded by Chlamydia, a successful computational method termed I-TASSER was utilized to model the three-dimensional structure of a hypothetical protein encoded by open reading frame (ORF) CT296. CT296 has been reported to exhibit functional properties of a divalent cation transcription repressor (DcrA), with similarity to the Escherichia coli iron-responsive transcriptional repressor, Fur. Unexpectedly, the I-TASSER model of CT296 exhibited no structural similarity to any DNA-interacting proteins or motifs. To validate the I-TASSER-generated model, the structure of CT296 was solved experimentally using X-ray crystallography. Impressively, the ab initio I-TASSER-generated model closely matched (2.72-Å C(α) root mean square deviation [RMSD]) the high-resolution (1.8-Å) crystal structure of CT296. Modeled and experimentally determined structures of CT296 share structural characteristics of non-heme Fe(II) 2-oxoglutarate-dependent enzymes, although key enzymatic residues are not conserved, suggesting a unique biochemical process is likely associated with CT296 function. Additionally, functional analyses did not support prior reports that CT296 has properties shared with divalent cation repressors such as Fur.
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Clifton IJ, Ge W, Adlington RM, Baldwin JE, Rutledge PJ. Isopenicillin N Synthase Binds δ-(L-α-Aminoadipoyl)-L-Cysteinyl-D-Thia-allo-Isoleucine through both Sulfur Atoms. Chembiochem 2011; 12:1881-5. [DOI: 10.1002/cbic.201100149] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Indexed: 11/08/2022]
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Ge W, Clifton IJ, Stok JE, Adlington RM, Baldwin JE, Rutledge PJ. Crystallographic studies on the binding of selectively deuterated LLD- and LLL-substrate epimers by isopenicillin N synthase. Biochem Biophys Res Commun 2010; 398:659-64. [DOI: 10.1016/j.bbrc.2010.06.129] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2010] [Accepted: 06/30/2010] [Indexed: 10/19/2022]
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Dungan VJ, Ortin Y, Mueller-Bunz H, Rutledge PJ. Design and synthesis of a tetradentate ‘3-amine-1-carboxylate’ ligand to mimic the metal binding environment at the non-heme iron(ii) oxidase active site. Org Biomol Chem 2010; 8:1666-73. [DOI: 10.1039/b921934j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ge W, Clifton IJ, Stok JE, Adlington RM, Baldwin JE, Rutledge PJ. The crystal structure of anlll-configured depsipeptide substrate analogue bound to isopenicillin N synthase. Org Biomol Chem 2010; 8:122-7. [DOI: 10.1039/b910170e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Ge W, Clifton IJ, Howard-Jones AR, Stok JE, Adlington RM, Baldwin JE, Rutledge PJ. Structural Studies on the Reaction of Isopenicillin N Synthase with a Sterically Demanding Depsipeptide Substrate Analogue. Chembiochem 2009; 10:2025-31. [DOI: 10.1002/cbic.200900080] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Bruijnincx PCA, van Koten G, Klein Gebbink RJM. Mononuclear non-heme iron enzymes with the 2-His-1-carboxylate facial triad: recent developments in enzymology and modeling studies. Chem Soc Rev 2008; 37:2716-44. [DOI: 10.1039/b707179p] [Citation(s) in RCA: 412] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Stewart AC, Clifton IJ, Adlington RM, Baldwin JE, Rutledge PJ. A Cyclobutanone Analogue Mimics Penicillin in Binding to Isopenicillin N Synthase. Chembiochem 2007; 8:2003-7. [PMID: 17907118 DOI: 10.1002/cbic.200700176] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A carbocyclic analogue of the beta-lactam antibiotic isopenicillin N (IPN) has been synthesised and cocrystallised with isopenicillin N synthase (IPNS), the central enzyme in the biosynthesis of penicillin antibiotics. The crystal structure of the IPNS-cyclobutanone complex reveals an active site environment similar to that seen in the enzyme-product complex generated by turnover of the natural substrate within the crystalline protein. The IPNS-cyclobutanone structure demonstrates that the product analogue is tethered to the protein by hydrogen bonding and salt bridge interactions with its carboxylate groups, as seen previously for the natural substrate and product. Furthermore, the successful cocrystallisation of this analogue with IPNS provides firm structural evidence for the utility of such cyclobutanone derivatives as hydrolytically stable analogues of bicyclic beta-lactams.
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Affiliation(s)
- Amanda C Stewart
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
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