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Zheng YY, Chung WH, Leung YC, Wong KY. Heterogenous Expression and Purification of Lipid II Flippase from Staphylococcus aureus. Protein Pept Lett 2024; 31:386-394. [PMID: 38967080 PMCID: PMC11348468 DOI: 10.2174/0109298665316374240531113258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/14/2024] [Accepted: 05/21/2024] [Indexed: 07/06/2024]
Abstract
BACKGROUND Staphylococcus aureus is a common pathogen with strains that are resistant to existing antibiotics. MurJ from S. aureus (SaMurJ), an integral membrane protein functioning as Lipid II flippase, is a potential target for developing new antibacterial agents against this pathogen. Successful expression and purification of this protein shall be useful in the development of drugs against this target. OBJECTIVE In this study, we demonstrated the optimized expression and purification procedures of SaMurJ, identified suitable detergent for extracting and solubilizing the protein, and examined the peptidisc system to generate a detergent-free environment. METHODS SaMurJ fused with N-terminal ten-His tag was expressed without induction. Six detergents were selected for screening the most efficient candidate for extraction and solubilization of the protein. The thermostability of the detergent-solubilized protein was assessed by evaluated temperature incubation. Different ratios of peptidisc bi-helical peptide (NSPr) to SaMurJ were mixed and the on-bead peptidisc assembly method was applied. RESULTS SaMurJ expressed in BL21(DE3) was confirmed by peptide fingerprinting, with a yield of 1 mg SaMurJ per liter culture. DDM was identified as the optimum detergent for solubilization and the nickel affinity column enabled SaMurJ purification with a purity of ~88%. However, NSPr could not stabilize SaMurJ. CONCLUSION The expression and purification of SaMurJ were successful, with high purity and good yield. SaMurJ can be solubilized and stabilized by a DDM-containing buffer.
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Affiliation(s)
- Yuan Yuan Zheng
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Wai-Hong Chung
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Yun-Chung Leung
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Kwok-Yin Wong
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
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Kumar S, Mollo A, Rubino FA, Kahne D, Ruiz N. Chloride Ions Are Required for Thermosipho africanus MurJ Function. mBio 2023; 14:e0008923. [PMID: 36752629 PMCID: PMC9973255 DOI: 10.1128/mbio.00089-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 01/17/2023] [Indexed: 02/09/2023] Open
Abstract
Most bacteria have a peptidoglycan cell wall that determines their cell shape and helps them resist osmotic lysis. Peptidoglycan synthesis depends on the translocation of the lipid-linked precursor lipid II across the cytoplasmic membrane by the MurJ flippase. Structure-function analyses of MurJ from Thermosipho africanus (MurJTa) and Escherichia coli (MurJEc) have revealed that MurJ adopts multiple conformations and utilizes an alternating-access mechanism to flip lipid II. MurJEc activity relies on membrane potential, but the specific counterion has not been identified. Crystal structures of MurJTa revealed a chloride ion bound to the N-lobe of the flippase and a sodium ion in its C-lobe, but the role of these ions in transport is unknown. Here, we investigated the effect of various ions on the function of MurJTa and MurJEc in vivo. We found that chloride, and not sodium, ions are necessary for MurJTa function, but neither ion is required for MurJEc function. We also showed that murJTa alleles encoding changes at the crystallographically identified sodium-binding site still complement the loss of native murJEc, although they decreased protein stability and/or function. Based on our data and previous work, we propose that chloride ions are necessary for the conformational change that resets MurJTa after lipid II translocation and suggest that MurJ orthologs may function similarly but differ in their requirements for counterions. IMPORTANCE The biosynthetic pathway of the peptidoglycan cell wall is one of the most favorable targets for antibiotic development. Lipid II, the lipid-linked PG precursor, is made in the inner leaflet of the cytoplasmic membrane and then transported by the MurJ flippase so that it can be used to build the peptidoglycan cell wall. MurJ functions using an alternating-access mechanism thought to depend on a yet-to-be-identified counterion. This study fills a gap in our understanding of MurJ's energy-coupling mechanism by showing that chloride ions are required for MurJ in some, but not all, organisms. Based on our data and prior studies, we propose that, while the general transport mechanism of MurJ may be conserved, its specific mechanistic details may differ across bacteria, as is common in transporters. These findings are important to understand MurJ function and its development as an antibiotic target.
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Affiliation(s)
- Sujeet Kumar
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Aurelio Mollo
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Frederick A. Rubino
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Daniel Kahne
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Natividad Ruiz
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
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Adler BA, Chamakura K, Carion H, Krog J, Deutschbauer AM, Young R, Mutalik VK, Arkin AP. Multicopy suppressor screens reveal convergent evolution of single-gene lysis proteins. Nat Chem Biol 2023; 19:759-766. [PMID: 36805702 DOI: 10.1038/s41589-023-01269-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 01/18/2023] [Indexed: 02/22/2023]
Abstract
Single-strand RNA (ssRNA) Fiersviridae phages cause host lysis with a product of single gene (sgl for single-gene lysis; product Sgl) that induces autolysis. Many different Sgls have been discovered, but the molecular targets of only a few have been identified. In this study, we used a high-throughput genetic screen to uncover genome-wide host suppressors of diverse Sgls. In addition to validating known molecular mechanisms, we discovered that the Sgl of PP7, an ssRNA phage of Pseudomonas aeruginosa, targets MurJ, the flippase responsible for lipid II export, previously shown to be the target of the Sgl of coliphage M. These two Sgls, which are unrelated and predicted to have opposite membrane topology, thus represent a case of convergent evolution. We extended the genetic screens to other uncharacterized Sgls and uncovered a common set of multicopy suppressors, suggesting that these Sgls act by the same or similar mechanism.
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Affiliation(s)
- Benjamin A Adler
- The UC Berkeley-UCSF Graduate Program in Bioengineering, Berkeley, CA, USA.,Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA.,Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Karthik Chamakura
- Department of Biochemistry and Biophysics, Center for Phage Technology, Texas A&M University, College Station, TX, USA.,Armata Pharmaceuticals, Inc., Marina Del Rey, CA, USA
| | - Heloise Carion
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA
| | - Jonathan Krog
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA
| | - Adam M Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Ry Young
- Department of Biochemistry and Biophysics, Center for Phage Technology, Texas A&M University, College Station, TX, USA
| | - Vivek K Mutalik
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA. .,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Adam P Arkin
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA. .,Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA. .,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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Antimicrobial Activity of Rhenium Di- and Tricarbonyl Diimine Complexes: Insights on Membrane-Bound S. aureus Protein Binding. Pharmaceuticals (Basel) 2022; 15:ph15091107. [PMID: 36145328 PMCID: PMC9501577 DOI: 10.3390/ph15091107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/31/2022] [Accepted: 08/31/2022] [Indexed: 11/16/2022] Open
Abstract
Antimicrobial resistance is one of the major human health threats, with significant impacts on the global economy. Antibiotics are becoming increasingly ineffective as drug-resistance spreads, imposing an urgent need for new and innovative antimicrobial agents. Metal complexes are an untapped source of antimicrobial potential. Rhenium complexes, amongst others, are particularly attractive due to their low in vivo toxicity and high antimicrobial activity, but little is known about their targets and mechanism of action. In this study, a series of rhenium di- and tricarbonyl diimine complexes were prepared and evaluated for their antimicrobial potential against eight different microorganisms comprising Gram-negative and -positive bacteria. Our data showed that none of the Re dicarbonyl or neutral tricarbonyl species have either bactericidal or bacteriostatic potential. In order to identify possible targets of the molecules, and thus possibly understand the observed differences in the antimicrobial efficacy of the molecules, we computationally evaluated the binding affinity of active and inactive complexes against structurally characterized membrane-bound S. aureus proteins. The computational analysis indicates two possible major targets for this class of compounds, namely lipoteichoic acids flippase (LtaA) and lipoprotein signal peptidase II (LspA). Our results, consistent with the published in vitro studies, will be useful for the future design of rhenium tricarbonyl diimine-based antibiotics.
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