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Recsei C, Russell RA, Cagnes M, Darwish T. Deuterated squalene and sterols from modified Saccharomyces cerevisiae. Org Biomol Chem 2023; 21:6537-6548. [PMID: 37523212 DOI: 10.1039/d3ob00754e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
Uniformly deuterated sterols and biosynthetically related materials are important for neutron, NMR, tracing and bioanalysis studies as well as critical tools for the creation of improved lipid nanoparticle formulations. The production of sufficient quantities of materials relies not only on the engineering of microorganisms to selectively accumulate desired materials but also methods for the isolation, purification and characterisation of these materials to ensure their usefulness. Uniformly deuterated squalene, the universal precursor to sterols in biological systems, has been produced and characterised. Cholesterol has been produced with controlled levels of uniform deuteration, increased biosynthetic yield and a methodology developed for the extraction and purification of this material without HPLC. Two sterols, not previously produced in deuterated forms, have been prepared with uniform deuteration: 22,23-dihydrobrassicasterol and 24-methylenecholesterol. This report triples the number of sterols that have been produced with uniform deuteration, purified and characterised and provides a silylation/silver ion chromatography protocol for the separation of sterols which differ by the degree of unsaturation. The techniques for the 13C NMR analysis of deuterated sterols, site-specific deuteration levels and an analysis of key biosynthetic steps based on these data are reported.
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Affiliation(s)
- Carl Recsei
- Australian Nuclear Science and Technology Organisation, National Deuteration Facility, New Illawarra Rd, Lucas Heights, New South Wales, 2234, Australia.
| | - Robert A Russell
- Australian Nuclear Science and Technology Organisation, National Deuteration Facility, New Illawarra Rd, Lucas Heights, New South Wales, 2234, Australia.
| | - Marina Cagnes
- Australian Nuclear Science and Technology Organisation, National Deuteration Facility, New Illawarra Rd, Lucas Heights, New South Wales, 2234, Australia.
| | - Tamim Darwish
- Australian Nuclear Science and Technology Organisation, National Deuteration Facility, New Illawarra Rd, Lucas Heights, New South Wales, 2234, Australia.
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Petit GA, Hong Y, Djoko KY, Whitten AE, Furlong EJ, McCoy AJ, Gulbis JM, Totsika M, Martin JL, Halili MA. The suppressor of copper sensitivity protein C from Caulobacter crescentus is a trimeric disulfide isomerase that binds copper(I) with subpicomolar affinity. ACTA CRYSTALLOGRAPHICA SECTION D STRUCTURAL BIOLOGY 2022; 78:337-352. [PMID: 35234148 PMCID: PMC8900818 DOI: 10.1107/s2059798322000729] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 01/21/2022] [Indexed: 11/10/2022]
Abstract
The characterization of the suppressor of copper sensitivity protein C from C. crescentus is reported. The introduction of disulfide bonds into periplasmic proteins is a critical process in many Gram-negative bacteria. The formation and regulation of protein disulfide bonds have been linked to the production of virulence factors. Understanding the different pathways involved in this process is important in the development of strategies to disarm pathogenic bacteria. The well characterized disulfide bond-forming (DSB) proteins play a key role by introducing or isomerizing disulfide bonds between cysteines in substrate proteins. Curiously, the suppressor of copper sensitivity C proteins (ScsCs), which are part of the bacterial copper-resistance response, share structural and functional similarities with DSB oxidase and isomerase proteins, including the presence of a catalytic thioredoxin domain. However, the oxidoreductase activity of ScsC varies with its oligomerization state, which depends on a poorly conserved N-terminal domain. Here, the structure and function of Caulobacter crescentus ScsC (CcScsC) have been characterized. It is shown that CcScsC binds copper in the copper(I) form with subpicomolar affinity and that its isomerase activity is comparable to that of Escherichia coli DsbC, the prototypical dimeric bacterial isomerase. It is also reported that CcScsC functionally complements trimeric Proteus mirabilis ScsC (PmScsC) in vivo, enabling the swarming of P. mirabilis in the presence of copper. Using mass photometry and small-angle X-ray scattering (SAXS) the protein is demonstrated to be trimeric in solution, like PmScsC, and not dimeric like EcDsbC. The crystal structure of CcScsC was also determined at a resolution of 2.6 Å, confirming the trimeric state and indicating that the trimerization results from interactions between the N-terminal α-helical domains of three CcScsC protomers. The SAXS data analysis suggested that the protomers are dynamic, like those of PmScsC, and are able to sample different conformations in solution.
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Petit GA, Mohanty B, McMahon RM, Nebl S, Hilko DH, Wilde KL, Scanlon MJ, Martin JL, Halili MA. Identification and characterization of two drug-like fragments that bind to the same cryptic binding pocket of Burkholderia pseudomallei DsbA. Acta Crystallogr D Struct Biol 2022; 78:75-90. [PMID: 34981764 PMCID: PMC8725163 DOI: 10.1107/s2059798321011475] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 10/29/2021] [Indexed: 01/10/2023] Open
Abstract
Disulfide-bond-forming proteins (Dsbs) play a crucial role in the pathogenicity of many Gram-negative bacteria. Disulfide-bond-forming protein A (DsbA) catalyzes the formation of the disulfide bonds necessary for the activity and stability of multiple substrate proteins, including many virulence factors. Hence, DsbA is an attractive target for the development of new drugs to combat bacterial infections. Here, two fragments, bromophenoxy propanamide (1) and 4-methoxy-N-phenylbenzenesulfonamide (2), were identified that bind to DsbA from the pathogenic bacterium Burkholderia pseudomallei, the causative agent of melioidosis. The crystal structures of oxidized B. pseudomallei DsbA (termed BpsDsbA) co-crystallized with 1 or 2 show that both fragments bind to a hydrophobic pocket that is formed by a change in the side-chain orientation of Tyr110. This conformational change opens a `cryptic' pocket that is not evident in the apoprotein structure. This binding location was supported by 2D-NMR studies, which identified a chemical shift perturbation of the Tyr110 backbone amide resonance of more than 0.05 p.p.m. upon the addition of 2 mM fragment 1 and of more than 0.04 p.p.m. upon the addition of 1 mM fragment 2. Although binding was detected by both X-ray crystallography and NMR, the binding affinity (Kd) for both fragments was low (above 2 mM), suggesting weak interactions with BpsDsbA. This conclusion is also supported by the crystal structure models, which ascribe partial occupancy to the ligands in the cryptic binding pocket. Small fragments such as 1 and 2 are not expected to have a high energetic binding affinity due to their relatively small surface area and the few functional groups that are available for intermolecular interactions. However, their simplicity makes them ideal for functionalization and optimization. The identification of the binding sites of 1 and 2 to BpsDsbA could provide a starting point for the development of more potent novel antimicrobial compounds that target DsbA and bacterial virulence.
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Affiliation(s)
- Guillaume A. Petit
- Griffith Institute for Drug Discovery, Griffith University, Building N75, 46 Don Young Road, Nathan, QLD 4111, Australia
| | - Biswaranjan Mohanty
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- ARC Centre for Fragment-Based Design, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- Sydney Analytical Core Research Facility, The University of Sydney, Sydney, NSW 2006, Australia
| | - Róisín M. McMahon
- Griffith Institute for Drug Discovery, Griffith University, Building N75, 46 Don Young Road, Nathan, QLD 4111, Australia
| | - Stefan Nebl
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - David H. Hilko
- Griffith Institute for Drug Discovery, Griffith University, Building N75, 46 Don Young Road, Nathan, QLD 4111, Australia
| | - Karyn L. Wilde
- National Deuteration Facility, Australian Nuclear Science and Technology Organization (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Martin J. Scanlon
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- ARC Centre for Fragment-Based Design, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Jennifer L. Martin
- Griffith Institute for Drug Discovery, Griffith University, Building N75, 46 Don Young Road, Nathan, QLD 4111, Australia
- Vice-Chancellor’s Unit, University of Wollongong, Building 36, Wollongong, NSW 2522, Australia
| | - Maria A. Halili
- Griffith Institute for Drug Discovery, Griffith University, Building N75, 46 Don Young Road, Nathan, QLD 4111, Australia
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Littler DR, Mohanty B, Lowery SA, Colson RN, Gully BS, Perlman S, Scanlon MJ, Rossjohn J. Binding of a pyrimidine RNA base-mimic to SARS-CoV-2 nonstructural protein 9. J Biol Chem 2021; 297:101018. [PMID: 34331944 PMCID: PMC8317483 DOI: 10.1016/j.jbc.2021.101018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 01/18/2023] Open
Abstract
The coronaviral nonstructural protein 9 (Nsp9) is essential for viral replication; it is the primary substrate of Nsp12's pseudokinase domain within the viral replication transcription complex, an association that also recruits other components during different stages of RNA reproduction. In the unmodified state, Nsp9 forms an obligate homodimer via an essential GxxxG protein-interaction motif, but its ssRNA-binding mechanism remains unknown. Using structural biological techniques, here we show that a base-mimicking compound identified from a small molecule fragment screen engages Nsp9 via a tetrameric Pi-Pi stacking interaction that induces the formation of a parallel trimer-of-dimers. This oligomerization mechanism allows an interchange of "latching" N-termini, the charges of which contribute to a series of electropositive channels that suggests a potential interface for viral RNA. The identified pyrrolo-pyrimidine compound may also serve as a potential starting point for the development of compounds seeking to probe Nsp9's role within SARS-CoV-2 replication.
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Affiliation(s)
- Dene R Littler
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
| | - Biswaranjan Mohanty
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia; Sydney Analytical Core Research Facility, The University of Sydney, Sydney, New South Wales, Australia; ARC Centre for Fragment-Based Design, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Shea A Lowery
- Department of Microbiology and Immunology, University of Iowa, Iowa City, Iowa, USA
| | - Rhys N Colson
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Benjamin S Gully
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Stanley Perlman
- Department of Microbiology and Immunology, University of Iowa, Iowa City, Iowa, USA
| | - Martin J Scanlon
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia; ARC Centre for Fragment-Based Design, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia.
| | - Jamie Rossjohn
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Institute of Infection and Immunity, Cardiff University School of Medicine, Cardiff, United Kingdom.
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Norton RS, Jahnke W. NMR in pharmaceutical discovery and development. JOURNAL OF BIOMOLECULAR NMR 2020; 74:473-476. [PMID: 32886261 DOI: 10.1007/s10858-020-00345-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 08/23/2020] [Indexed: 06/11/2023]
Affiliation(s)
- Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia.
- ARC Centre for Fragment-Based Design, Monash University, Parkville, VIC, 3052, Australia.
| | - Wolfgang Jahnke
- Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, Virchow-16.3.249, 4002, Basel, Switzerland.
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