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Huh H, Shen J, Ajjugal Y, Ramachandran A, Patel SS, Lee SH. Sequence-specific dynamic DNA bending explains mitochondrial TFAM's dual role in DNA packaging and transcription initiation. Nat Commun 2024; 15:5446. [PMID: 38937458 PMCID: PMC11211510 DOI: 10.1038/s41467-024-49728-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 06/17/2024] [Indexed: 06/29/2024] Open
Abstract
Mitochondrial transcription factor A (TFAM) employs DNA bending to package mitochondrial DNA (mtDNA) into nucleoids and recruit mitochondrial RNA polymerase (POLRMT) at specific promoter sites, light strand promoter (LSP) and heavy strand promoter (HSP). Herein, we characterize the conformational dynamics of TFAM on promoter and non-promoter sequences using single-molecule fluorescence resonance energy transfer (smFRET) and single-molecule protein-induced fluorescence enhancement (smPIFE) methods. The DNA-TFAM complexes dynamically transition between partially and fully bent DNA conformational states. The bending/unbending transition rates and bending stability are DNA sequence-dependent-LSP forms the most stable fully bent complex and the non-specific sequence the least, which correlates with the lifetimes and affinities of TFAM with these DNA sequences. By quantifying the dynamic nature of the DNA-TFAM complexes, our study provides insights into how TFAM acts as a multifunctional protein through the DNA bending states to achieve sequence specificity and fidelity in mitochondrial transcription while performing mtDNA packaging.
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Affiliation(s)
- Hyun Huh
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, 08854, USA
| | - Jiayu Shen
- Graduate School of Biomedical Sciences, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, 08854, USA
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, 08854, USA
| | - Yogeeshwar Ajjugal
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, 08854, USA
| | - Aparna Ramachandran
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, 08854, USA
| | - Smita S Patel
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, 08854, USA.
| | - Sang-Hyuk Lee
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, 08854, USA.
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA.
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Jiang J, Keniya MV, Puri A, Zhan X, Cheng J, Wang H, Lin G, Lee YK, Jaber N, Hassoun Y, Shor E, Shi Z, Lee SH, Xu M, Perlin DS, Dai W. Structural and Biophysical Dynamics of Fungal Plasma Membrane Proteins and Implications for Echinocandin Action in Candida glabrata. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.29.596243. [PMID: 38854035 PMCID: PMC11160696 DOI: 10.1101/2024.05.29.596243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Fungal plasma membrane proteins represent key therapeutic targets for antifungal agents, yet their structure and spatial distribution in the native context remain poorly characterized. Herein, we employ an integrative multimodal approach to elucidate the structural and functional organization of plasma membrane protein complexes in Candida glabrata , focusing on prominent and essential membrane proteins, the polysaccharide synthase β-(1,3)-glucan synthase (GS) and the proton pump Pma1. Cryo-electron tomography (cryo-ET) and live cell imaging reveal that GS and Pma1 are heterogeneously distributed into distinct plasma membrane microdomains. Treatment with caspofungin, an echinocandin antifungal that targets GS, alters the plasma membrane and disrupts the native distribution of GS and Pma1. Based on these findings, we propose a model for echinocandin action that considers how drug interactions with the plasma membrane environment lead to inhibition of GS. Our work underscores the importance of interrogating the structural and dynamic characteristics of fungal plasma membrane proteins in situ to understand function and facilitate precisely targeted development of novel antifungal therapies.
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Savin N, Erofeev A, Gorelkin P. Analytical Models for Measuring the Mechanical Properties of Yeast. Cells 2023; 12:1946. [PMID: 37566025 PMCID: PMC10417110 DOI: 10.3390/cells12151946] [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: 06/05/2023] [Revised: 07/21/2023] [Accepted: 07/26/2023] [Indexed: 08/12/2023] Open
Abstract
The mechanical properties of yeast play an important role in many biological processes, such as cell division and growth, maintenance of internal pressure, and biofilm formation. In addition, the mechanical properties of cells can indicate the degree of damage caused by antifungal drugs, as the mechanical parameters of healthy and damaged cells are different. Over the past decades, atomic force microscopy (AFM) and micromanipulation have become the most widely used methods for evaluating the mechanical characteristics of microorganisms. In this case, the reliability of such an estimate depends on the choice of mathematical model. This review presents various analytical models developed in recent years for studying the mechanical properties of both cells and their individual structures. The main provisions of the applied approaches are described along with their limitations and advantages. Attention is paid to the innovative method of low-invasive nanomechanical mapping with scanning ion-conductance microscopy (SICM), which is currently starting to be successfully used in the discovery of novel drugs acting on the yeast cell wall and plasma membrane.
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Affiliation(s)
- Nikita Savin
- Research Laboratory of Biophysics, National University of Science and Technology MISiS, Moscow 119049, Russia;
| | - Alexander Erofeev
- Research Laboratory of Biophysics, National University of Science and Technology MISiS, Moscow 119049, Russia;
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Magazzù A, Marcuello C. Investigation of Soft Matter Nanomechanics by Atomic Force Microscopy and Optical Tweezers: A Comprehensive Review. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13060963. [PMID: 36985857 PMCID: PMC10053849 DOI: 10.3390/nano13060963] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/28/2023] [Accepted: 03/02/2023] [Indexed: 05/17/2023]
Abstract
Soft matter exhibits a multitude of intrinsic physico-chemical attributes. Their mechanical properties are crucial characteristics to define their performance. In this context, the rigidity of these systems under exerted load forces is covered by the field of biomechanics. Moreover, cellular transduction processes which are involved in health and disease conditions are significantly affected by exogenous biomechanical actions. In this framework, atomic force microscopy (AFM) and optical tweezers (OT) can play an important role to determine the biomechanical parameters of the investigated systems at the single-molecule level. This review aims to fully comprehend the interplay between mechanical forces and soft matter systems. In particular, we outline the capabilities of AFM and OT compared to other classical bulk techniques to determine nanomechanical parameters such as Young's modulus. We also provide some recent examples of nanomechanical measurements performed using AFM and OT in hydrogels, biopolymers and cellular systems, among others. We expect the present manuscript will aid potential readers and stakeholders to fully understand the potential applications of AFM and OT to soft matter systems.
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Affiliation(s)
- Alessandro Magazzù
- CNR-IPCF, Istituto per i Processi Chimico-Fisici, 98158 Mesina, Italy
- NLHT-Lab, Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Carlos Marcuello
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
- Correspondence: ; Tel.: +34-876555357
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5
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Optical trapping and fluorescence control with vectorial structured light. Sci Rep 2022; 12:17690. [PMID: 36271234 DOI: 10.1038/s41598-022-21224-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/23/2022] [Indexed: 11/08/2022] Open
Abstract
Here we functionalized micro-scaled polymer beads with nano-scaled quantum dots and demonstrate optical trapping and tweezing, with in-situ fluorescence measurement, in an all-digital all-optical configuration. We outline the chemistry required to facilitate this, from deactivating the optical trapping environment to size, adhesion and agglomeration control. We introduce a novel holographic optical trapping set-up that leverages on vectorially structured light, allowing for the delivery of tuneable forms of light from purely scalar to purely vector, including propagation invariant flat-top beams for uniform illumination and tailored intensity gradient landscapes. Finally, we show how this has the potential to quench bleaching in a single wavelength trap by linear (spatial mode) rather than non-linear effects, advancing the nascent field of optics for chemistry.
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Atwal S, Wongsantichon J, Giengkam S, Saharat K, Pittayasathornthun YJ, Chuenklin S, Wang LC, Chung T, Huh H, Lee SH, Sobota RM, Salje J. The obligate intracellular bacterium Orientia tsutsugamushi differentiates into a developmentally distinct extracellular state. Nat Commun 2022; 13:3603. [PMID: 35739103 PMCID: PMC9226355 DOI: 10.1038/s41467-022-31176-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 06/03/2022] [Indexed: 11/13/2022] Open
Abstract
Orientia tsutsugamushi (Ot) is an obligate intracellular bacterium in the family Rickettsiaceae that causes scrub typhus, a severe mite-borne human disease. Its mechanism of cell exit is unusual amongst Rickettsiaceae, as Ot buds off the surface of infected cells enveloped in plasma membrane. Here, we show that Ot bacteria that have budded out of host cells are in a distinct developmental stage compared with intracellular bacteria. We refer to these two stages as intracellular and extracellular bacteria (IB and EB, respectively). These two forms differ in physical properties: IB is both round and elongated, and EB is round. Additionally, IB has higher levels of peptidoglycan and is physically robust compared with EB. The two bacterial forms differentially express proteins involved in bacterial physiology and host-pathogen interactions, specifically those involved in bacterial dormancy and stress response, and outer membrane autotransporter proteins ScaA and ScaC. Whilst both populations are infectious, entry of IB Ot is sensitive to inhibitors of both clathrin-mediated endocytosis and macropinocytosis, whereas entry of EB Ot is only sensitive to a macropinocytosis inhibitor. Our identification and detailed characterization of two developmental forms of Ot significantly advances our understanding of the intracellular lifecycle of an important human pathogen. Orientia tsutsugamushi (Ot) the causing agent of scrub typhus exits infected cells using a unique mechanism that involves budding off the surface of infected cells. Here, Atwal et al. report that Ots that have budded from their host cells are in a distinct developmental stage than intracellular bacteria and provide the first characterization of this extracellular stage. Both forms are infectious but differ in their physical properties, proteome, and entry mechanism into host cells.
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Affiliation(s)
- Sharanjeet Atwal
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA
| | - Jantana Wongsantichon
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Suparat Giengkam
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kittirat Saharat
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA
| | | | - Suthida Chuenklin
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Loo Chien Wang
- Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.,SingMass-National Mass Spectrometry Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Taerin Chung
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, USA
| | - Hyun Huh
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, USA
| | - Sang-Hyuk Lee
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, USA.,Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Radoslaw M Sobota
- Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.,SingMass-National Mass Spectrometry Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Jeanne Salje
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA. .,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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Impact of FtsZ Inhibition on the Localization of the Penicillin Binding Proteins in Methicillin-Resistant Staphylococcus aureus. J Bacteriol 2021; 203:e0020421. [PMID: 34031040 DOI: 10.1128/jb.00204-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant pathogen of acute clinical importance. Combination treatment with an FtsZ inhibitor potentiates the activity of penicillin binding protein (PBP)-targeting β-lactam antibiotics against MRSA. To explore the mechanism underlying this synergistic behavior, we examined the impact of treatment with the FtsZ inhibitor TXA707 on the spatial localization of the five PBP proteins expressed in MRSA. In the absence of drug treatment, PBP1, PBP2, PBP3, and PBP4 colocalize with FtsZ at the septum, contributing to new cell wall formation. In contrast, PBP2a localizes to distinct foci along the cell periphery. Upon treatment with TXA707, septum formation becomes disrupted, and FtsZ relocalizes away from midcell. PBP1 and PBP3 remain significantly colocalized with FtsZ, while PBP2, PBP4, and PBP2a localize away from FtsZ to specific sites along the periphery of the enlarged cells. We also examined the impact on PBP2a and PBP2 localization of treatment with β-lactam antibiotic oxacillin alone and in synergistic combination with TXA707. Significantly, PBP2a localizes to the septum in approximately 15% of the oxacillin-treated cells, a behavior that likely contributes to the β-lactam resistance of MRSA. Combination treatment with TXA707 causes both PBP2a and PBP2 to localize in malformed septum-like structures. Our collective results suggest that PBP2, PBP4, and PBP2a may function collaboratively in peripheral cell wall repair and maintenance in response to FtsZ inhibition by TXA707. Cotreatment with oxacillin appears to reduce the availability of PBP2a to assist in this repair, thereby rendering the MRSA cells more susceptible to the β-lactam. IMPORTANCE MRSA is a multidrug-resistant bacterial pathogen of acute clinical importance, infecting many thousands of individuals globally each year. The essential cell division protein FtsZ has been identified as an appealing target for the development of new drugs to combat MRSA infections. Through synergistic actions, FtsZ-targeting agents can sensitize MRSA to antibiotics like the β-lactams that would otherwise be ineffective. This study provides key insights into the mechanism underlying this synergistic behavior as well as MRSA resistance to β-lactam drugs. The results of this work will help guide the identification and optimization of combination drug regimens that can effectively treat MRSA infections and reduce the potential for future resistance.
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Ma G, Hu C, Li S, Gao X, Li H, Hu X. Simultaneous, hybrid single-molecule method by optical tweezers and fluorescence. NANOTECHNOLOGY AND PRECISION ENGINEERING 2019. [DOI: 10.1016/j.npe.2019.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Liu B, Hobson CM, Pimenta FM, Nelsen E, Hsiao J, O'Brien T, Falvo MR, Hahn KM, Superfine R. VIEW-MOD: a versatile illumination engine with a modular optical design for fluorescence microscopy. OPTICS EXPRESS 2019; 27:19950-19972. [PMID: 31503749 DOI: 10.1364/oe.27.019950] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 06/19/2019] [Indexed: 05/18/2023]
Abstract
We developed VIEW-MOD (Versatile Illumination Engine with a Modular Optical Design): a compact, multi-modality microscope, which accommodates multiple illumination schemes including variable angle total internal reflection, point scanning and vertical/horizontal light sheet. This system allows combining and flexibly switching between different illuminations and imaging modes by employing three electrically tunable lenses and two fast-steering mirrors. This versatile optics design provides control of 6 degrees of freedom of the illumination source (3 translation, 2 tilt, and beam shape) plus the axial position of the imaging plane. We also developed standalone software with an easy-to-use GUI to calibrate and control the microscope. We demonstrate the applications of this system and software in biosensor imaging, optogenetics and fast 3D volume imaging. This system is ready to fit into complex imaging circumstances requiring precise control of illumination and detection paths, and has a broad scope of usability for a myriad of biological applications.
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