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Zhao X, Gao Y, Gong Q, Zhang K, Li S. Elucidating the Architectural dynamics of MuB filaments in bacteriophage Mu DNA transposition. Nat Commun 2024; 15:6445. [PMID: 39085263 PMCID: PMC11292022 DOI: 10.1038/s41467-024-50722-1] [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: 02/19/2024] [Accepted: 07/18/2024] [Indexed: 08/02/2024] Open
Abstract
MuB is a non-specific DNA-binding protein and AAA+ ATPase that significantly influences the DNA transposition process of bacteriophage Mu, especially in target DNA selection for transposition. While studies have established the ATP-dependent formation of MuB filament as pivotal to this process, the high-resolution structure of a full-length MuB protomer and the underlying molecular mechanisms governing its oligomerization remain elusive. Here, we use cryo-EM to obtain a 3.4-Å resolution structure of the ATP(+)-DNA(+)-MuB helical filament, which encapsulates the DNA substrate within its axial channel. The structure categorizes MuB within the initiator clade of the AAA+ protein family and precisely locates the ATP and DNA binding sites. Further investigation into the oligomeric states of MuB show the existence of various forms of the filament. These findings lead to a mechanistic model where MuB forms opposite helical filaments along the DNA, exposing potential target sites on the bare DNA and then recruiting MuA, which stimulates MuB's ATPase activity and disrupts the previously formed helical structure. When this happens, MuB generates larger ring structures and dissociates from the DNA.
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Affiliation(s)
- Xiaolong Zhao
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yongxiang Gao
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Qingguo Gong
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Kaiming Zhang
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
| | - Shanshan Li
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
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Mindrebo JT, Lander GC. Structural and mechanistic studies on human LONP1 redefine the hand-over-hand translocation mechanism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.24.600538. [PMID: 38979310 PMCID: PMC11230189 DOI: 10.1101/2024.06.24.600538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
AAA+ enzymes use energy from ATP hydrolysis to remodel diverse cellular targets. Structures of substrate-bound AAA+ complexes suggest that these enzymes employ a conserved hand-over-hand mechanism to thread substrates through their central pore. However, the fundamental aspects of the mechanisms governing motor function and substrate processing within specific AAA+ families remain unresolved. We used cryo-electron microscopy to structurally interrogate reaction intermediates from in vitro biochemical assays to inform the underlying regulatory mechanisms of the human mitochondrial AAA+ protease, LONP1. Our results demonstrate that substrate binding allosterically regulates proteolytic activity, and that LONP1 can adopt a configuration conducive to substrate translocation even when the ATPases are bound to ADP. These results challenge the conventional understanding of the hand-over-hand translocation mechanism, giving rise to an alternative model that aligns more closely with biochemical and biophysical data on related enzymes like ClpX, ClpA, the 26S proteasome, and Lon protease.
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Affiliation(s)
- Jeffrey T. Mindrebo
- Department of Integrative Structural and Computational Biology, Scripps Research; La Jolla, CA, USA
| | - Gabriel C. Lander
- Department of Integrative Structural and Computational Biology, Scripps Research; La Jolla, CA, USA
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Li S, Hsieh KY, Kuo CI, Lin TC, Lee SH, Chen YR, Wang CH, Ho MR, Ting SY, Zhang K, Chang CI. A 5+1 assemble-to-activate mechanism of the Lon proteolytic machine. Nat Commun 2023; 14:7340. [PMID: 37957149 PMCID: PMC10643698 DOI: 10.1038/s41467-023-43035-2] [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: 09/28/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023] Open
Abstract
Many AAA+ (ATPases associated with diverse cellular activities) proteins function as protein or DNA remodelers by threading the substrate through the central pore of their hexameric assemblies. In this ATP-dependent translocating state, the substrate is gripped by the pore loops of the ATPase domains arranged in a universal right-handed spiral staircase organization. However, the process by which a AAA+ protein is activated to adopt this substrate-pore-loop arrangement remains unknown. We show here, using cryo-electron microscopy (cryo-EM), that the activation process of the Lon AAA+ protease may involve a pentameric assembly and a substrate-dependent incorporation of the sixth protomer to form the substrate-pore-loop contacts seen in the translocating state. Based on the structural results, we design truncated monomeric mutants that inhibit Lon activity by binding to the native pentamer and demonstrated that expressing these monomeric mutants in Escherichia coli cells containing functional Lon elicits specific phenotypes associated with lon deficiency, including the inhibition of persister cell formation. These findings uncover a substrate-dependent assembly process for the activation of a AAA+ protein and demonstrate a targeted approach to selectively inhibit its function within cells.
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Affiliation(s)
- Shanshan Li
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, 230001, Hefei, China.
| | - Kan-Yen Hsieh
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Chiao-I Kuo
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Tzu-Chi Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Szu-Hui Lee
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Yi-Ru Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Chun-Hsiung Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Meng-Ru Ho
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - See-Yeun Ting
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Kaiming Zhang
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, 230001, Hefei, China.
| | - Chung-I Chang
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan.
- Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, 10617, Taiwan.
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Xu W, Gao W, Bu Q, Li Y. Degradation Mechanism of AAA+ Proteases and Regulation of Streptomyces Metabolism. Biomolecules 2022; 12:biom12121848. [PMID: 36551276 PMCID: PMC9775585 DOI: 10.3390/biom12121848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/02/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Hundreds of proteins work together in microorganisms to coordinate and control normal activity in cells. Their degradation is not only the last step in the cell's lifespan but also the starting point for its recycling. In recent years, protein degradation has been extensively studied in both eukaryotic and prokaryotic organisms. Understanding the degradation process is essential for revealing the complex regulatory network in microorganisms, as well as further artificial reconstructions and applications. This review will discuss several studies on protein quality-control family members Lon, FtsH, ClpP, the proteasome in Streptomyces, and a few classical model organisms, mainly focusing on their structure, recognition mechanisms, and metabolic influences.
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Affiliation(s)
- Weifeng Xu
- Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou 310058, China
| | - Wenli Gao
- Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou 310058, China
| | - Qingting Bu
- Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou 310058, China
| | - Yongquan Li
- Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou 310058, China
- Correspondence:
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Yang J, Song AS, Wiseman RL, Lander GC. Cryo-EM structure of hexameric yeast Lon protease (PIM1) highlights the importance of conserved structural elements. J Biol Chem 2022; 298:101694. [PMID: 35143841 PMCID: PMC8913295 DOI: 10.1016/j.jbc.2022.101694] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 11/26/2022] Open
Abstract
Lon protease is a conserved ATP-dependent serine protease composed of an AAA+ domain that mechanically unfolds substrates and a serine protease domain that degrades these unfolded substrates. In yeast, dysregulation of Lon protease (PIM1) attenuates lifespan and leads to gross mitochondrial morphological perturbations. Although structures of the bacterial and human Lon protease reveal a hexameric assembly, yeast PIM1 was speculated to form a heptameric assembly and is uniquely characterized by a ∼50-residue insertion between the ATPase and protease domains. To further understand the yeast-specific properties of PIM1, we determined a high-resolution cryo-electron microscopy structure of PIM1 in a substrate-translocating state. Here, we reveal that PIM1 forms a hexamer, conserved with that of bacterial and human Lon proteases, wherein the ATPase domains form a canonical closed spiral that enables pore loop residues to translocate substrates to the protease chamber. In the substrate-translocating state, PIM1 protease domains form a planar protease chamber in an active conformation and are uniquely characterized by a ∼15-residue C-terminal extension. These additional C-terminal residues form an α-helix located along the base of the protease domain. Finally, we did not observe density for the yeast-specific insertion between the ATPase and protease domains, likely due to high conformational flexibility. Biochemical studies to investigate the insertion using constructs that truncated or replaced the insertion with a glycine-serine linker suggest that the yeast-specific insertion is dispensable for PIM1's enzymatic function. Altogether, our structural and biochemical studies highlight unique components of PIM1 machinery and demonstrate evolutionary conservation of Lon protease function.
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Affiliation(s)
- Jie Yang
- Department of Integrative, Structural and Computational Biology, Scripps Research, La Jolla, California, USA
| | - Albert S Song
- Department of Integrative, Structural and Computational Biology, Scripps Research, La Jolla, California, USA; Department of Molecular Medicine, Scripps Research, La Jolla, California, USA
| | - R Luke Wiseman
- Department of Molecular Medicine, Scripps Research, La Jolla, California, USA.
| | - Gabriel C Lander
- Department of Integrative, Structural and Computational Biology, Scripps Research, La Jolla, California, USA.
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Wlodawer A, Sekula B, Gustchina A, Rotanova TV. Structure and the mode of activity of Lon proteases from diverse organisms. J Mol Biol 2022; 434:167504. [PMID: 35183556 PMCID: PMC9013511 DOI: 10.1016/j.jmb.2022.167504] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/14/2022] [Accepted: 02/14/2022] [Indexed: 11/19/2022]
Abstract
Lon proteases, members of the AAA+ superfamily of enzymes, are key components of the protein quality control system in bacterial cells, as well as in the mitochondria and other specialized organelles of higher organisms. These enzymes have been subject of extensive biochemical and structural investigations, resulting in 72 crystal and solution structures, including structures of the individual domains, multi-domain constructs, and full-length proteins. However, interpretation of the latter structures still leaves some questions unanswered. Based on their amino acid sequence and details of their structure, Lon proteases can be divided into at least three subfamilies, designated as LonA, LonB, and LonC. Protomers of all Lons are single-chain polypeptides and contain two functional domains, ATPase and protease. The LonA enzymes additionally include a large N-terminal region, and different Lons may also include non-conserved inserts in the principal domains. These ATP-dependent proteases function as homohexamers, in which unfolded substrates are translocated to a large central chamber where they undergo proteolysis by a processive mechanism. X-ray crystal structures provided high-resolution models which verified that Lons are hydrolases with the rare Ser-Lys catalytic dyad. Full-length LonA enzymes have been investigated by cryo-electron microscopy (cryo-EM), providing description of the functional enzyme at different stages of the catalytic cycle, indicating extensive flexibility of their N-terminal domains, and revealing insights into the substrate translocation mechanism. Structural studies of Lon proteases provide an interesting case for symbiosis of X-ray crystallography and cryo-EM, currently the two principal techniques for determination of macromolecular structures.
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Affiliation(s)
- Alexander Wlodawer
- Protein Structure Section, Center for Structural Biology, National Cancer Institute, Frederick, MD 21702, USA.
| | - Bartosz Sekula
- Protein Structure Section, Center for Structural Biology, National Cancer Institute, Frederick, MD 21702, USA
| | - Alla Gustchina
- Protein Structure Section, Center for Structural Biology, National Cancer Institute, Frederick, MD 21702, USA
| | - Tatyana V Rotanova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
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Li S, Hsieh KY, Kuo CI, Su SC, Huang KF, Zhang K, Chang CI. Processive cleavage of substrate at individual proteolytic active sites of the Lon protease complex. SCIENCE ADVANCES 2021; 7:eabj9537. [PMID: 34757797 PMCID: PMC8580320 DOI: 10.1126/sciadv.abj9537] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
The Lon protease is the prototype of a family of proteolytic machines with adenosine triphosphatase modules built into a substrate degradation chamber. Lon is known to degrade protein substrates in a processive fashion, cutting a protein chain processively into small peptides before commencing cleavages of another protein chain. Here, we present structural and biochemical evidence demonstrating that processive substrate degradation occurs at each of the six proteolytic active sites of Lon, which forms a deep groove that partially encloses the substrate polypeptide chain by accommodating only the unprimed residues and permits processive cleavage in the C-to-N direction. We identify a universally conserved acidic residue at the exit side of the binding groove indispensable for the proteolytic activity. This noncatalytic residue likely promotes processive proteolysis by carboxyl-carboxylate interactions with cleaved intermediates. Together, these results uncover a previously unrecognized mechanism for processive substrate degradation by the Lon protease.
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Affiliation(s)
- Shanshan Li
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale and Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Kan-Yen Hsieh
- Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Chiao-I Kuo
- Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Shih-Chieh Su
- Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Kai-Fa Huang
- Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Kaiming Zhang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale and Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Chung-I Chang
- Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
- Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei 10617, Taiwan
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