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De-la-Torre P, Martínez-García C, Gratias P, Mun M, Santana P, Akyuz N, González W, Indzhykulian AA, Ramírez D. Identification of Druggable Binding Sites and Small Molecules as Modulators of TMC1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.05.583611. [PMID: 38826329 PMCID: PMC11142246 DOI: 10.1101/2024.03.05.583611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Our ability to hear and maintain balance relies on the proper functioning of inner ear sensory hair cells, which translate mechanical stimuli into electrical signals via mechano-electrical transducer (MET) channels, composed of TMC1/2 proteins. However, the therapeutic use of ototoxic drugs, such as aminoglycosides and cisplatin, which can enter hair cells through MET channels, often leads to profound auditory and vestibular dysfunction. Despite extensive research on otoprotective compounds targeting MET channels, our understanding of how small molecule modulators interact with these channels remains limited, hampering the discovery of novel compounds. Here, we propose a structure-based screening approach, integrating 3D-pharmacophore modeling, molecular simulations, and experimental validation. Our pipeline successfully identified several novel compounds and FDA-approved drugs that reduced dye uptake in cultured cochlear explants, indicating MET modulation activity. Molecular docking and free-energy estimations for binding allowed us to identify three potential drug binding sites within the channel pore, phospholipids, and key amino acids involved in modulator interactions. We also identified shared ligand-binding features between TMC and structurally related TMEM16 protein families, providing novel insights into their distinct inhibition, while potentially guiding the rational design of MET-channel-specific modulators. Our pipeline offers a broad application to discover small molecule modulators for a wide spectrum of mechanosensitive ion channels.
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Affiliation(s)
- Pedro De-la-Torre
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Mass Eye and Ear, Boston, MA, USA
| | | | - Paul Gratias
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Mass Eye and Ear, Boston, MA, USA
| | - Matthew Mun
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Mass Eye and Ear, Boston, MA, USA
| | - Paula Santana
- Facultad de Ingeniería, Instituto de Ciencias Químicas Aplicadas, Universidad Autónoma de Chile, Santiago, Chile
| | - Nurunisa Akyuz
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Wendy González
- Center for Bioinformatics and Molecular Simulations (CBSM), University of Talca, Talca 3460000, Chile
| | - Artur A. Indzhykulian
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Mass Eye and Ear, Boston, MA, USA
| | - David Ramírez
- Department of Pharmacology, Faculty of Biological Sciences, University of Concepción, Chile
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2
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Arora N, Hazra JP, Roy S, Bhati GK, Gupta S, Yogendran KP, Chaudhuri A, Sagar A, Rakshit S. Emergence of slip-ideal-slip behavior in tip-links serve as force filters of sound in hearing. Nat Commun 2024; 15:1595. [PMID: 38383683 PMCID: PMC10881517 DOI: 10.1038/s41467-024-45423-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 01/23/2024] [Indexed: 02/23/2024] Open
Abstract
Tip-links in the inner ear convey force from sound and trigger mechanotransduction. Here, we present evidence that tip-links (collectively as heterotetrameric complexes of cadherins) function as force filters during mechanotransduction. Our force-clamp experiments reveal that the tip-link complexes show slip-ideal-slip bond dynamics. At low forces, the lifetime of the tip-link complex drops monotonically, indicating slip-bond dynamics. The ideal bond, rare in nature, is seen in an intermediate force regime where the survival of the complex remains constant over a wide range. At large forces, tip-links follow a slip bond and dissociate entirely to cut-off force transmission. In contrast, the individual tip-links (heterodimers) display slip-catch-slip bonds to the applied forces. While with a phenotypic mutant, we showed the importance of the slip-catch-slip bonds in uninterrupted hearing, our coarse-grained Langevin dynamics simulations demonstrated that the slip-ideal-slip bonds emerge as a collective feature from the slip-catch-slip bonds of individual tip-links.
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Affiliation(s)
- Nisha Arora
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Jagadish P Hazra
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Sandip Roy
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Gaurav K Bhati
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Sarika Gupta
- National Institute of Immunology, New Delhi, India
| | - K P Yogendran
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Abhishek Chaudhuri
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India.
| | - Amin Sagar
- Centre de Biologie Structurale, INSERM, CNRS, Université de Montpellier, Montpellier, France.
| | - Sabyasachi Rakshit
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India.
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3
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Lu S, Chemla YR. Optical traps induce fluorophore photobleaching by two-photon excitation. Biophys J 2023; 122:4316-4325. [PMID: 37828742 PMCID: PMC10698272 DOI: 10.1016/j.bpj.2023.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/20/2023] [Accepted: 10/10/2023] [Indexed: 10/14/2023] Open
Abstract
Techniques combining optical tweezers with fluorescence microscopy have become increasingly popular. Unfortunately, the high-power, infrared lasers used to create optical traps can have a deleterious effect on dye stability. Previous studies have shown that dye photobleaching is enhanced by absorption of visible fluorescence excitation plus infrared trap photons, a process that can be significantly reduced by minimizing simultaneous exposure to both light sources. Here, we report another photobleaching pathway that results from direct excitation by the trapping laser alone. Our results show that this trap-induced fluorescence loss is a two-photon absorption process, as demonstrated by a quadratic dependence on the intensity of the trapping laser. We further show that, under conditions typical of many trap-based experiments, fluorescence emission of certain fluorophores near the trap focus can drop by 90% within 1 min. We investigate how photostability is affected by the choice of dye molecule, excitation and emission wavelength, and labeled molecule. Finally, we discuss the different photobleaching pathways in combined trap-fluorescence measurements, which guide the selection of optimal dyes and conditions for more robust experimental protocols.
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Affiliation(s)
- Suoang Lu
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Yann R Chemla
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois; Center of the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois.
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4
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Mulhall EM, Gharpure A, Lee RM, Dubin AE, Aaron JS, Marshall KL, Spencer KR, Reiche MA, Henderson SC, Chew TL, Patapoutian A. Direct observation of the conformational states of PIEZO1. Nature 2023; 620:1117-1125. [PMID: 37587339 PMCID: PMC10468401 DOI: 10.1038/s41586-023-06427-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 07/11/2023] [Indexed: 08/18/2023]
Abstract
PIEZOs are mechanosensitive ion channels that convert force into chemoelectric signals1,2 and have essential roles in diverse physiological settings3. In vitro studies have proposed that PIEZO channels transduce mechanical force through the deformation of extensive blades of transmembrane domains emanating from a central ion-conducting pore4-8. However, little is known about how these channels interact with their native environment and which molecular movements underlie activation. Here we directly observe the conformational dynamics of the blades of individual PIEZO1 molecules in a cell using nanoscopic fluorescence imaging. Compared with previous structural models of PIEZO1, we show that the blades are significantly expanded at rest by the bending stress exerted by the plasma membrane. The degree of expansion varies dramatically along the length of the blade, where decreased binding strength between subdomains can explain increased flexibility of the distal blade. Using chemical and mechanical modulators of PIEZO1, we show that blade expansion and channel activation are correlated. Our findings begin to uncover how PIEZO1 is activated in a native environment. More generally, as we reliably detect conformational shifts of single nanometres from populations of channels, we expect that this approach will serve as a framework for the structural analysis of membrane proteins through nanoscopic imaging.
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Affiliation(s)
- Eric M Mulhall
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA
| | - Anant Gharpure
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA
| | - Rachel M Lee
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
| | - Adrienne E Dubin
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA
| | - Jesse S Aaron
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
| | - Kara L Marshall
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kathryn R Spencer
- Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA
| | - Michael A Reiche
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
| | - Scott C Henderson
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
| | - Teng-Leong Chew
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
| | - Ardem Patapoutian
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA.
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5
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Shrestha P, Yang D, Shih WM, Wong WP. Mapping Single-molecule Protein Complexes in 3D with DNA Nanoswitch Calipers. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.10.548386. [PMID: 37502860 PMCID: PMC10369884 DOI: 10.1101/2023.07.10.548386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The ability to accurately map the 3D geometry of single-molecule complexes in trace samples would lead to new insights into molecular mechanics and provide an approach for single-molecule structural proteomics. To enable this, we have developed a high-resolution force-spectroscopy method capable of measuring multiple distances between labeled sites in natively folded protein complexes. Our approach combines reconfigurable nanoscale devices we call DNA Nanoswitch Calipers, which we have previously introduced, with a force-based barcoding system to distinguish each measurement location. We demonstrate our approach by reconstructing the tetrahedral geometry of biotin-binding sites in natively folded streptavidin, with 1.5-2.5 Å agreement to previously reported structures.
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6
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Ivanchenko MV, Hathaway DM, Klein AJ, Pan B, Strelkova O, De-la-Torre P, Wu X, Peters CW, Mulhall EM, Booth KT, Goldstein C, Brower J, Sotomayor M, Indzhykulian AA, Corey DP. Mini-PCDH15 gene therapy rescues hearing in a mouse model of Usher syndrome type 1F. Nat Commun 2023; 14:2400. [PMID: 37100771 PMCID: PMC10133396 DOI: 10.1038/s41467-023-38038-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 04/11/2023] [Indexed: 04/28/2023] Open
Abstract
Usher syndrome type 1 F (USH1F), caused by mutations in the protocadherin-15 gene (PCDH15), is characterized by congenital deafness, lack of balance, and progressive blindness. In hair cells, the receptor cells of the inner ear, PCDH15 is a component of tip links, fine filaments which pull open mechanosensory transduction channels. A simple gene addition therapy for USH1F is challenging because the PCDH15 coding sequence is too large for adeno-associated virus (AAV) vectors. We use rational, structure-based design to engineer mini-PCDH15s in which 3-5 of the 11 extracellular cadherin repeats are deleted, but which still bind a partner protein. Some mini-PCDH15s can fit in an AAV. An AAV encoding one of these, injected into the inner ears of mouse models of USH1F, produces a mini-PCDH15 which properly forms tip links, prevents the degeneration of hair cell bundles, and rescues hearing. Mini-PCDH15s may be a useful therapy for the deafness of USH1F.
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Affiliation(s)
| | - Daniel M Hathaway
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Alex J Klein
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Bifeng Pan
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Olga Strelkova
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Pedro De-la-Torre
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Xudong Wu
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Cole W Peters
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Eric M Mulhall
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Kevin T Booth
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Corey Goldstein
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Joseph Brower
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Artur A Indzhykulian
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - David P Corey
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.
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7
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Qiu X, Müller U. Sensing sound: Cellular specializations and molecular force sensors. Neuron 2022; 110:3667-3687. [PMID: 36223766 PMCID: PMC9671866 DOI: 10.1016/j.neuron.2022.09.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/03/2022] [Accepted: 09/14/2022] [Indexed: 11/08/2022]
Abstract
Organisms of all phyla express mechanosensitive ion channels with a wide range of physiological functions. In recent years, several classes of mechanically gated ion channels have been identified. Some of these ion channels are intrinsically mechanosensitive. Others depend on accessory proteins to regulate their response to mechanical force. The mechanotransduction machinery of cochlear hair cells provides a particularly striking example of a complex force-sensing machine. This molecular ensemble is embedded into a specialized cellular compartment that is crucial for its function. Notably, mechanotransduction channels of cochlear hair cells are not only critical for auditory perception. They also shape their cellular environment and regulate the development of auditory circuitry. Here, we summarize recent discoveries that have shed light on the composition of the mechanotransduction machinery of cochlear hair cells and how this machinery contributes to the development and function of the auditory system.
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Affiliation(s)
- Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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8
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Ding X, Wang Z, Zheng B, Shi S, Deng Y, Yu H, Zheng P. One-step asparaginyl endopeptidase ( OaAEP1)-based protein immobilization for single-molecule force spectroscopy. RSC Chem Biol 2022; 3:1276-1281. [PMID: 36320890 PMCID: PMC9533667 DOI: 10.1039/d2cb00135g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/18/2022] [Indexed: 11/22/2022] Open
Abstract
Enzymatic protein ligation has become the most powerful and widely used method for high-precision atomic force microscopy single-molecule force spectroscopy (AFM-SMFS) study of protein mechanics. However, this methodology typically requires the functionalization of the glass surface with a corresponding peptide sequence/tag for enzymatic recognition and multiple steps are needed. Thus, it is time-consuming and a high level of experience is needed for reliable results. To solve this problem, we simplified the procedure using two strategies both based on asparaginyl endopeptidase (AEP). First, we designed a heterobifunctional peptide-based crosslinker, GL-peptide-propargylglycine, which links to an N 3-functionalized surface via the click reaction. Then, the target protein with a C-terminal NGL sequence can be immobilized via the AEP-mediated ligation. Furthermore, we took advantage of the direct ligation between primary amino in a small molecule and protein with C-terminal NGL by AEP. Thus, the target protein can be immobilized on an amino-functionalized surface via AEP in one step. Both approaches were successfully applied to the AFM-SMFS study of eGFP, showing consistent single-molecule results.
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Affiliation(s)
- Xuan Ding
- Department of Biomedical Engineering, College of Engineering and Applied Sciences, Nanjing University 163 Xianlin Road Nanjing Jiangsu 210023 P. R. China
- State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University Nanjing Jiangsu 210023 P. R. China
| | - Ziyi Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
| | - Bin Zheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
| | - Shengchao Shi
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
| | - Yibing Deng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
| | - Hanyang Yu
- Department of Biomedical Engineering, College of Engineering and Applied Sciences, Nanjing University 163 Xianlin Road Nanjing Jiangsu 210023 P. R. China
| | - Peng Zheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
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9
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Shi S, Wu T, Zheng P. Direct Measurements of the Cobalt-thiolate Bonds Strength in Rubredoxin by Single-Molecule Force Spectroscopy. Chembiochem 2022; 23:e202200165. [PMID: 35475313 DOI: 10.1002/cbic.202200165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/26/2022] [Indexed: 11/07/2022]
Abstract
Cobalt is a trace transition metal. Although it is not abundant on earth, tens of cobalt-containing proteins exist in life. Moreover, the characteristic spectrum of Co(II) ion makes it a powerful probe for the characterization of metal-binding proteins through the formation of cobalt-ligand bonds. Since most of these natural and artificial cobalt-containing proteins are stable, we believe that these cobalt-ligand bonds in the protein system are also mechanically stable. To prove this, we used atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) to directly measure the rupture force of Co(II)-thiolate bond in Co-substituted rubredoxin (CoRD). By combining the chemical denature/renature method for building metalloprotein and cysteine coupling-based polyprotein construction strategy, we successfully prepared the polyprotein sample (CoRD) n suitable for single-molecule study. Thus, we quantified the strength of Co(II)-thiolate bonds in rubredoxin with a rupture force of ~140 pN, revealing that the bond is a stable chemical bond. In addition, the Co-S bond is more labile than the Zn-S bond in proteins, similar to the result from the metal-competing titration experiment.
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Affiliation(s)
- Shengchao Shi
- Nanjing University, School of Chemistry and Chemical Engineering, CHINA
| | - Tao Wu
- Nanjing University, School of Chemistry and Chemical Engineering, CHINA
| | - Peng Zheng
- Nanjing University, School of Chemistry and Chemical Engineering, 168 Xianlin Ave, Nanjing, Jiangsu Province, 210023, Nanjing, CHINA
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10
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Abstract
In the dynamic environment of the airways, where SARS-CoV-2 infections are initiated by binding to human host receptor ACE2, mechanical stability of the viral attachment is a crucial fitness advantage. Using single-molecule force spectroscopy techniques, we mimic the effect of coughing and sneezing, thereby testing the force stability of SARS-CoV-2 RBD:ACE2 interaction under physiological conditions. Our results reveal a higher force stability of SARS-CoV-2 binding to ACE2 compared to SARS-CoV-1, causing a possible fitness advantage. Our assay is sensitive to blocking agents preventing RBD:ACE2 bond formation. It will thus provide a powerful approach to investigate the modes of action of neutralizing antibodies and other agents designed to block RBD binding to ACE2 that are currently developed as potential COVID-19 therapeutics. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are initiated by attachment of the receptor-binding domain (RBD) on the viral Spike protein to angiotensin-converting enzyme-2 (ACE2) on human host cells. This critical first step occurs in dynamic environments, where external forces act on the binding partners and avidity effects play an important role, creating an urgent need for assays that can quantitate SARS-CoV-2 interactions with ACE2 under mechanical load. Here, we introduce a tethered ligand assay that comprises the RBD and the ACE2 ectodomain joined by a flexible peptide linker. Using magnetic tweezers and atomic force spectroscopy as highly complementary single-molecule force spectroscopy techniques, we investigate the RBD:ACE2 interaction over the whole physiologically relevant force range. We combine the experimental results with steered molecular dynamics simulations and observe and assign fully consistent unbinding and unfolding events across the three techniques, enabling us to establish ACE2 unfolding as a molecular fingerprint. Measuring at forces of 2 to 5 pN, we quantify the force dependence and kinetics of the RBD:ACE2 bond in equilibrium. We show that the SARS-CoV-2 RBD:ACE2 interaction has higher mechanical stability, larger binding free energy, and a lower dissociation rate compared to SARS-CoV-1, which helps to rationalize the different infection patterns of the two viruses. By studying how free ACE2 outcompetes tethered ACE2, we show that our assay is sensitive to prevention of bond formation by external binders. We expect our results to provide a way to investigate the roles of viral mutations and blocking agents for targeted pharmaceutical intervention.
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11
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Mechanotransduction in mammalian sensory hair cells. Mol Cell Neurosci 2022; 120:103706. [PMID: 35218890 PMCID: PMC9177625 DOI: 10.1016/j.mcn.2022.103706] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 02/14/2022] [Accepted: 02/18/2022] [Indexed: 11/23/2022] Open
Abstract
In the inner ear, the auditory and vestibular systems detect and translate sensory information regarding sound and balance. The sensory cells that transform mechanical input into an electrical signal in these systems are called hair cells. A specialized organelle on the apical surface of the hair cells called the hair bundle detects the mechanical signals. Displacement of the hair bundle causes mechanotransduction channels to open. The morphology and organization of the hair bundle, as well as the properties and characteristics of the mechanotransduction process, differ between the different hair cell types in the auditory and vestibular systems. These differences likely contribute to maximizing the transduction of specific signals in each system. This review will discuss the molecules essential for mechanotransduction and the properties of the mechanotransduction process, focusing our attention on recent data and differences between the auditory and vestibular systems.
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12
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Elferich J, Clark S, Ge J, Goehring A, Matsui A, Gouaux E. Molecular structures and conformations of protocadherin-15 and its complexes on stereocilia elucidated by cryo-electron tomography. eLife 2021; 10:74512. [PMID: 34964715 PMCID: PMC8776254 DOI: 10.7554/elife.74512] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 12/27/2021] [Indexed: 11/23/2022] Open
Abstract
Mechanosensory transduction (MT), the conversion of mechanical stimuli into electrical signals, underpins hearing and balance and is carried out within hair cells in the inner ear. Hair cells harbor actin-filled stereocilia, arranged in rows of descending heights, where the tips of stereocilia are connected to their taller neighbors by a filament composed of protocadherin 15 (PCDH15) and cadherin 23 (CDH23), deemed the ‘tip link.’ Tension exerted on the tip link opens an ion channel at the tip of the shorter stereocilia, thus converting mechanical force into an electrical signal. While biochemical and structural studies have provided insights into the molecular composition and structure of isolated portions of the tip link, the architecture, location, and conformational states of intact tip links, on stereocilia, remains unknown. Here, we report in situ cryo-electron microscopy imaging of the tip link in mouse stereocilia. We observe individual PCDH15 molecules at the tip and shaft of stereocilia and determine their stoichiometry, conformational heterogeneity, and their complexes with other filamentous proteins, perhaps including CDH23. The PCDH15 complexes occur in clusters, frequently with more than one copy of PCDH15 at the tip of stereocilia, suggesting that tip links might consist of more than one copy of PCDH15 complexes and, by extension, might include multiple MT complexes.
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Affiliation(s)
- Johannes Elferich
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Sarah Clark
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Jingpeng Ge
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - April Goehring
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Aya Matsui
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Eric Gouaux
- Vollum Institute, Oregon Health and Science University, Portland, United States
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13
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Shrestha P, Yang D, Tomov TE, MacDonald JI, Ward A, Bergal HT, Krieg E, Cabi S, Luo Y, Nathwani B, Johnson-Buck A, Shih WM, Wong WP. Single-molecule mechanical fingerprinting with DNA nanoswitch calipers. NATURE NANOTECHNOLOGY 2021; 16:1362-1370. [PMID: 34675411 PMCID: PMC8678201 DOI: 10.1038/s41565-021-00979-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 08/16/2021] [Indexed: 05/31/2023]
Abstract
Decoding the identity of biomolecules from trace samples is a longstanding goal in the field of biotechnology. Advances in DNA analysis have substantially affected clinical practice and basic research, but corresponding developments for proteins face challenges due to their relative complexity and our inability to amplify them. Despite progress in methods such as mass spectrometry and mass cytometry, single-molecule protein identification remains a highly challenging objective. Towards this end, we combine DNA nanotechnology with single-molecule force spectroscopy to create a mechanically reconfigurable DNA nanoswitch caliper capable of measuring multiple coordinates on single biomolecules with atomic resolution. Using optical tweezers, we demonstrate absolute distance measurements with ångström-level precision for both DNA and peptides, and using multiplexed magnetic tweezers, we demonstrate quantification of relative abundance in mixed samples. Measuring distances between DNA-labelled residues, we perform single-molecule fingerprinting of synthetic and natural peptides, and show discrimination, within a heterogeneous population, between different posttranslational modifications. DNA nanoswitch calipers are a powerful and accessible tool for characterizing distances within nanoscale complexes that will enable new applications in fields such as single-molecule proteomics.
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Affiliation(s)
- Prakash Shrestha
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Darren Yang
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Toma E Tomov
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - James I MacDonald
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Andrew Ward
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Hans T Bergal
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Biophysics Program, Harvard University, Cambridge, MA, USA
| | - Elisha Krieg
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Serkan Cabi
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Yi Luo
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Bhavik Nathwani
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Alexander Johnson-Buck
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Biophysics Program, Harvard University, Cambridge, MA, USA
| | - William M Shih
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.
| | - Wesley P Wong
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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14
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Liu Y, Tian F, Shi S, Deng Y, Zheng P. Enzymatic Protein-Protein Conjugation through Internal Site Verified at the Single-Molecule Level. J Phys Chem Lett 2021; 12:10914-10919. [PMID: 34734720 DOI: 10.1021/acs.jpclett.1c02767] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Enzymes are widely used for protein ligation because of their efficient and site-specific connections under mild conditions. However, many enzymatic ligations are restricted to connections between protein termini while protein-protein conjugation at a specific internal site is limited. Previous work has found that Sortase A (SrtA) conjugates small molecules/peptides to a pilin protein at an internal lysine site via an isopeptide bond. Herein, we apply this noncanonical ligation property of SrtA for protein-protein conjugation at a designed YPKH site. Both a small protein domain, I27, and a large protein, GFP, were ligated at the designed internal site. Moreover, besides characterization by classic methods at the ensemble level, the specific ligation site at the interior YPKH motif is unambiguously verified by atomic force microscopy-based single-molecule force spectroscopy, showing the characteristic unfolding signature at the single-molecule level. Finally, steered molecular dynamics simulations also agreed with the results.
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Affiliation(s)
- Yutong Liu
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Fang Tian
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Shengchao Shi
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Yibing Deng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Peng Zheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
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15
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Nie J, Tian F, Zheng B, Wang Z, Zheng P. Exploration of Metal-Ligand Coordination Bonds in Proteins by Single-molecule Force Spectroscopy. CHEM LETT 2021. [DOI: 10.1246/cl.210307] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Jingyuan Nie
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P. R. China
| | - Fang Tian
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P. R. China
| | - Bin Zheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P. R. China
| | - Ziyi Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P. R. China
| | - Peng Zheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P. R. China
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16
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Arora N, Hazra JP, Rakshit S. Anisotropy in mechanical unfolding of protein upon partner-assisted pulling and handle-assisted pulling. Commun Biol 2021; 4:925. [PMID: 34326473 PMCID: PMC8322310 DOI: 10.1038/s42003-021-02445-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/07/2021] [Indexed: 02/07/2023] Open
Abstract
Proteins as force-sensors respond to mechanical cues and regulate signaling in physiology. Proteins commonly connect the source and response points of mechanical cues in two conformations, independent proteins in end-to-end geometry and protein complexes in handshake geometry. The force-responsive property of independent proteins in end-to-end geometry is studied extensively using single-molecule force spectroscopy (SMFS). The physiological significance of the complex conformations in force-sensing is often disregarded as mere surge protectors. However, with the potential of force-steering, protein complexes possess a distinct mechano-responsive property over individual force-sensors. To decipher, we choose a force-sensing protein, cadherin-23, from tip-link complex and perform SMFS using end-to-end geometry and handshake complex geometry. We measure higher force-resilience of cadherin-23 with preferential shorter extensions in handshake mode of pulling over the direct mode. The handshake geometry drives the force-response of cadherin-23 through different potential-energy landscapes than direct pulling. Analysis of the dynamic network structure of cadherin-23 under tension indicates narrow force-distributions among residues in cadherin-23 in direct pulling, resulting in low force-dissipation paths and low resilience to force. Overall, the distinct and superior mechanical responses of cadherin-23 in handshake geometry than single protein geometry highlight a probable evolutionary drive of protein-protein complexes as force-conveyors over independent ones.
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Affiliation(s)
- Nisha Arora
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Jagadish Prasad Hazra
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India.
| | - Sabyasachi Rakshit
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India.
- Centre for Protein Science Design and Engineering, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India.
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