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Zurawa-Janicka D, Wenta T, Jarzab M, Skorko-Glonek J, Glaza P, Gieldon A, Ciarkowski J, Lipinska B. Structural insights into the activation mechanisms of human HtrA serine proteases. Arch Biochem Biophys 2017; 621:6-23. [PMID: 28396256 DOI: 10.1016/j.abb.2017.04.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/05/2017] [Accepted: 04/06/2017] [Indexed: 12/21/2022]
Abstract
Human HtrA1-4 proteins belong to the HtrA family of evolutionarily conserved serine proteases and function as important modulators of many physiological processes, including maintenance of mitochondrial homeostasis, cell signaling and apoptosis. Disturbances in their action are linked to severe diseases, including oncogenesis and neurodegeneration. The HtrA1-4 proteins share structural and functional features of other members of the HtrA protein family, however there are several significant differences in structural architecture and mechanisms of action which makes each of them unique. Our goal is to present recent studies regarding human HtrAs. We focus on their physiological functions, structure and regulation, and describe current models of activation mechanisms. Knowledge of molecular basis of the human HtrAs' action is a subject of great interest; it is crucial for understanding their relevance in cellular physiology and pathogenesis as well as for using them as targets in future therapies of diseases such as neurodegenerative disorders and cancer.
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Affiliation(s)
- Dorota Zurawa-Janicka
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland.
| | - Tomasz Wenta
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Miroslaw Jarzab
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Joanna Skorko-Glonek
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Przemyslaw Glaza
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Artur Gieldon
- Department of Theoretical Chemistry, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland
| | - Jerzy Ciarkowski
- Department of Theoretical Chemistry, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland
| | - Barbara Lipinska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
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52
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Zhu F, Yang X, Wu Y, Wang Y, Tang XF, Tang B. Release of an HtrA-Like Protease from the Cell Surface of Thermophilic Brevibacillus sp. WF146 via Substrate-Induced Autoprocessing of the N-terminal Membrane Anchor. Front Microbiol 2017; 8:481. [PMID: 28377763 PMCID: PMC5359297 DOI: 10.3389/fmicb.2017.00481] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 03/08/2017] [Indexed: 01/07/2023] Open
Abstract
High-temperature requirement A (HtrA)-like proteases participate in protein quality control in prokaryotes and eukaryotes by degrading damaged proteins; however, little is known about HtrAs produced by thermophiles. HtrAw is an HtrA-like protease of thermophilic Brevibacillus sp. WF146. The intact form of HtrAw (iHtrAw) consisting of a transmembrane segment-containing N-terminal domain, a trypsin-like protease domain, and a C-terminal PDZ domain was produced in Escherichia coli. Purified iHtrAw itself is unable to cleave the N-terminal domain, but requires protein substrates to autoprocess the N-terminal domain intermolecularly, yielding a short form (sHtrAw). Mutation at the substrate-binding site in the PDZ domain affects the conversion of iHtrAw to sHtrAw. Deletion analysis revealed that the N-terminal domain is not necessary for enzyme folding, activity, and thermostability. Compared with other known HtrAs, HtrAw contains an additional Ca2+-binding Dx[DN]xDG motif important for enzyme stability and/or activity. When produced in an htrA/htrB double deletion mutant of Bacillus subtilis, iHtrAw localized predominantly to the cell pellet, and the amount of sHtrAw in the culture supernatant increased at elevated temperatures. Moreover, HtrAw increased the heat resistance of the B. subtilis mutant. In strain WF146, HtrAw exists in both a cell-associated intact form and a cell-free short form; an increase in growth temperature enhanced HtrAw production and the amount of cell-free short form. Release of the short form of HtrAw from the membrane may have the advantage of allowing the enzyme to freely access and degrade damaged proteins surrounding the bacterium living at high temperatures.
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Affiliation(s)
- Fengtao Zhu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University Wuhan, China
| | - Xing Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University Wuhan, China
| | - Yan Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University Wuhan, China
| | - Yasi Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University Wuhan, China
| | - Xiao-Feng Tang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan UniversityWuhan, China; Hubei Provincial Cooperative Innovation Center of Industrial FermentationWuhan, China
| | - Bing Tang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan UniversityWuhan, China; Hubei Provincial Cooperative Innovation Center of Industrial FermentationWuhan, China
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53
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Zhang L, Wang X, Fan F, Wang HW, Wang J, Li X, Sui SF. Cryo-EM structure of Nma111p, a unique HtrA protease composed of two protease domains and four PDZ domains. Cell Res 2017; 27:582-585. [PMID: 28084331 DOI: 10.1038/cr.2017.5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Li Zhang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaojing Wang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Fenghui Fan
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hong-Wei Wang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiawei Wang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xueming Li
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Sen-Fang Sui
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
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54
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Wessler S, Schneider G, Backert S. Bacterial serine protease HtrA as a promising new target for antimicrobial therapy? Cell Commun Signal 2017; 15:4. [PMID: 28069057 PMCID: PMC5223389 DOI: 10.1186/s12964-017-0162-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 01/04/2017] [Indexed: 12/19/2022] Open
Abstract
Recent studies have demonstrated that the bacterial chaperone and serine protease high temperature requirement A (HtrA) is closely associated with the establishment and progression of several infectious diseases. HtrA activity enhances bacterial survival under stress conditions, but also has direct effects on functions of the cell adhesion protein E-cadherin and extracellular matrix proteins, including fibronectin and proteoglycans. Although HtrA cannot be considered as a pathogenic factor per se, it exhibits favorable characteristics making HtrA a potentially attractive drug target to combat various bacterial infections.
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Affiliation(s)
- Silja Wessler
- Department of Molecular Biology, Division of Microbiology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria.
| | - Gisbert Schneider
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH), Vladimir-Prelog-Weg 4, CH-8093, Zürich, Switzerland
| | - Steffen Backert
- Division of Microbiology, University of Erlangen-Nuremberg, Staudtstr. 5, D-91058, Erlangen, Germany
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55
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Chang Z. The function of the DegP (HtrA) protein: Protease versus chaperone. IUBMB Life 2016; 68:904-907. [PMID: 27670951 DOI: 10.1002/iub.1561] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 09/06/2016] [Indexed: 11/06/2022]
Abstract
The DegP (or HtrA) is a highly conserved family of proteins functioning in all living organisms. It was initially identified as a protease functioning in the periplasmic space of the Gram-negative bacterial cells. It was later reported to also exhibit chaperone activity and thus has been designated as a bifunctional protein. However, recent studies demonstrated that in living cells it more likely functions only as a protease with hardly detectable chaperone activities. In this review, I will summarize the evidences clarifying that DegP more likely only functions as a protease rather than as a chaperone in cells. © 2016 IUBMB Life, 68(11):904-907, 2016.
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Affiliation(s)
- Zengyi Chang
- Center for Protein Science, State Key Laboratory of Protein and Plant Gene Studies, School of Life Sciences, Center for History and Philosophy of Science, Peking University, Beijing, China.
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56
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Wang HW, Lei J, Shi Y. Biological cryo-electron microscopy in China. Protein Sci 2016; 26:16-31. [PMID: 27534377 PMCID: PMC5192968 DOI: 10.1002/pro.3018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 08/11/2016] [Accepted: 08/11/2016] [Indexed: 12/16/2022]
Abstract
Cryo‐electron microscopy (cryo‐EM) plays an increasingly more important role in structural biology. With the construction of an arm of the Chinese National Protein Science Facility at Tsinghua University, biological cryo‐EM has entered a phase of rapid development in China. This article briefly reviews the history of biological cryo‐EM in China, describes its current status, comments on its impact on the various biological research fields, and presents future outlook.
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Affiliation(s)
- Hong-Wei Wang
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jianlin Lei
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
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57
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Distinct 3D Architecture and Dynamics of the Human HtrA2(Omi) Protease and Its Mutated Variants. PLoS One 2016; 11:e0161526. [PMID: 27571206 PMCID: PMC5003398 DOI: 10.1371/journal.pone.0161526] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 08/08/2016] [Indexed: 11/19/2022] Open
Abstract
HtrA2(Omi) protease controls protein quality in mitochondria and plays a major role in apoptosis. Its HtrA2S306A mutant (with the catalytic serine routinely disabled for an X-ray study to avoid self-degradation) is a homotrimer whose subunits contain the serine protease domain (PD) and the regulatory PDZ domain. In the inactive state, a tight interdomain interface limits penetration of both PDZ-activating ligands and PD substrates into their respective target sites. We successfully crystalized HtrA2V226K/S306A, whose active counterpart HtrA2V226K has had higher proteolytic activity, suggesting higher propensity to opening the PD-PDZ interface than that of the wild type HtrA2. Yet, the crystal structure revealed the HtrA2V226K/S306A architecture typical of the inactive protein. To get a consistent interpretation of crystallographic data in the light of kinetic results, we employed molecular dynamics (MD). V325D inactivating mutant was used as a reference. Our simulations demonstrated that upon binding of a specific peptide ligand NH2-GWTMFWV-COOH, the PDZ domains open more dynamically in the wild type protease compared to the V226K mutant, whereas the movement is not observed in the V325D mutant. The movement relies on a PDZ vs. PD rotation which opens the PD-PDZ interface in a lid-like (budding flower-like in trimer) fashion. The noncovalent hinges A and B are provided by two clusters of interfacing residues, harboring V325D and V226K in the C- and N-terminal PD barrels, respectively. The opening of the subunit interfaces progresses in a sequential manner during the 50 ns MD simulation. In the systems without the ligand only minor PDZ shifts relative to PD are observed, but the interface does not open. Further activation-associated events, e.g. PDZ-L3 positional swap seen in any active HtrA protein (vs. HtrA2), were not observed. In summary, this study provides hints on the mechanism of activation of wtHtrA2, the dynamics of the inactive HtrA2V325D, but does not allow to explain an increased activity of HtrA2V226K.
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58
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HtrA Is Important for Stress Resistance and Virulence in Haemophilus parasuis. Infect Immun 2016; 84:2209-2219. [PMID: 27217419 PMCID: PMC4962635 DOI: 10.1128/iai.00147-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/12/2016] [Indexed: 02/06/2023] Open
Abstract
Haemophilus parasuis is an opportunistic pathogen that causes Glässer's disease in swine, with polyserositis, meningitis, and arthritis. The high-temperature requirement A (HtrA)-like protease, which is involved in protein quality control, has been reported to be a virulence factor in many pathogens. In this study, we showed that HtrA of H. parasuis (HpHtrA) exhibited both chaperone and protease activities. Finally, nickel import ATP-binding protein (NikE), periplasmic dipeptide transport protein (DppA), and outer membrane protein A (OmpA) were identified as proteolytic substrates for HpHtrA. The protease activity reached its maximum at 40°C in a time-dependent manner. Disruption of the htrA gene from strain SC1401 affected tolerance to temperature stress and resistance to complement-mediated killing. Furthermore, increased autoagglutination and biofilm formation were detected in the htrA mutant. In addition, the htrA mutant was significantly attenuated in virulence in the murine model of infection. Together, these data demonstrate that HpHtrA plays an important role in the virulence of H. parasuis.
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59
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Rollauer SE, Sooreshjani MA, Noinaj N, Buchanan SK. Outer membrane protein biogenesis in Gram-negative bacteria. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2015.0023. [PMID: 26370935 DOI: 10.1098/rstb.2015.0023] [Citation(s) in RCA: 160] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Gram-negative bacteria contain a double membrane which serves for both protection and for providing nutrients for viability. The outermost of these membranes is called the outer membrane (OM), and it contains a host of fully integrated membrane proteins which serve essential functions for the cell, including nutrient uptake, cell adhesion, cell signalling and waste export. For pathogenic strains, many of these outer membrane proteins (OMPs) also serve as virulence factors for nutrient scavenging and evasion of host defence mechanisms. OMPs are unique membrane proteins in that they have a β-barrel fold and can range in size from 8 to 26 strands, yet can still serve many different functions for the cell. Despite their essential roles in cell survival and virulence, the exact mechanism for the biogenesis of these OMPs into the OM has remained largely unknown. However, the past decade has witnessed significant progress towards unravelling the pathways and mechanisms necessary for moulding a nascent polypeptide into a functional OMP within the OM. Here, we will review some of these recent discoveries that have advanced our understanding of the biogenesis of OMPs in Gram-negative bacteria, starting with synthesis in the cytoplasm to folding and insertion into the OM.
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Affiliation(s)
- Sarah E Rollauer
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Moloud A Sooreshjani
- Markey Center for Structural Biology, Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Nicholas Noinaj
- Markey Center for Structural Biology, Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Susan K Buchanan
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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60
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Abstract
The β-barrel outer membrane proteins (OMPs) are integral membrane proteins that reside in the outer membrane of Gram-negative bacteria and perform a diverse range of biological functions. Synthesized in the cytoplasm, OMPs must be transported across the inner membrane and through the periplasmic space before they are assembled in the outer membrane. In Escherichia coli, Skp, SurA and DegP are the most prominent factors identified to guide OMPs across the periplasm and to play the role of quality control. Although extensive genetic and biochemical analyses have revealed many basic functions of these periplasmic proteins, the mechanism of their collaboration in assisting the folding and insertion of OMPs is much less understood. Recently, biophysical approaches have shed light on the identification of the intricate network. In the present review, we summarize recent advances in the characterization of these key factors, with a special emphasis on the multifunctional protein DegP. In addition, we present our proposed model on the periplasmic quality control in biogenesis of OMPs.
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61
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Tegtmeyer N, Moodley Y, Yamaoka Y, Pernitzsch SR, Schmidt V, Traverso FR, Schmidt TP, Rad R, Yeoh KG, Bow H, Torres J, Gerhard M, Schneider G, Wessler S, Backert S. Characterisation of worldwide Helicobacter pylori strains reveals genetic conservation and essentiality of serine protease HtrA. Mol Microbiol 2015; 99:925-44. [PMID: 26568477 PMCID: PMC4832355 DOI: 10.1111/mmi.13276] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2015] [Indexed: 12/11/2022]
Abstract
HtrA proteases and chaperones exhibit important roles in periplasmic protein quality control and stress responses. The genetic inactivation of htrA has been described for many bacterial pathogens. However, in some cases such as the gastric pathogen Helicobacter pylori, HtrA is secreted where it cleaves the tumour‐suppressor E‐cadherin interfering with gastric disease development, but the generation of htrA mutants is still lacking. Here, we show that the htrA gene locus is highly conserved in worldwide strains. HtrA presence was confirmed in 992 H. pylori isolates in gastric biopsy material from infected patients. Differential RNA‐sequencing (dRNA‐seq) indicated that htrA is encoded in an operon with two subsequent genes, HP1020 and HP1021. Genetic mutagenesis and complementation studies revealed that HP1020 and HP1021, but not htrA, can be mutated. In addition, we demonstrate that suppression of HtrA proteolytic activity with a newly developed inhibitor is sufficient to effectively kill H. pylori, but not other bacteria. We show that Helicobacter
htrA is an essential bifunctional gene with crucial intracellular and extracellular functions. Thus, we describe here the first microbe in which htrA is an indispensable gene, a situation unique in the bacterial kingdom. HtrA can therefore be considered a promising new target for anti‐bacterial therapy.
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Affiliation(s)
- Nicole Tegtmeyer
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058, Erlangen, Germany.,Institut für Medizinische Mikrobiologie, Otto-von-Guericke Universität Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany
| | - Yoshan Moodley
- Department of Zoology, University of Venda, Private Bag X5050, Thohoyandou, 0950, South Africa.,Konrad-Lorenz-Institut für Vergleichende Verhaltensforschung, Department für Integrative Biologie und Evolution, Veterinärmedizinische Universität Wien, Savoyenstr. 1a, A-1160, Wien, Austria
| | - Yoshio Yamaoka
- Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Dept. Medicine-Gastroenterology, Houston, TX, USA.,Oita University Faculty of Medicine, Dept. Environmental and Preventive Medicine, Yufu, Japan
| | - Sandy Ramona Pernitzsch
- Research Center for Infectious Diseases (ZINF), University of Würzburg, Josef-Schneider-Str. 2/Bau D15, D-97080, Würzburg, Germany
| | - Vanessa Schmidt
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058, Erlangen, Germany
| | - Francisco Rivas Traverso
- Institut für Medizinische Mikrobiologie, Otto-von-Guericke Universität Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany
| | - Thomas P Schmidt
- Department of Molecular Biology, Division of Microbiology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria
| | - Roland Rad
- II Medical Department, Klinikum Rechts der Isar, Technical University Munich, Munich, Germany.,German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Khay Guan Yeoh
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ho Bow
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Javier Torres
- Unidad de Investigacion en Enfermedades Infecciosas, UMAE Pediatria, IMSS, Mexico City, Mexico
| | - Markus Gerhard
- Institut für Medizinische Mikrobiologie, Immunologie und Hygiene, Technische Universität München, Munich, 81675, Germany
| | - Gisbert Schneider
- ETH Zürich, Institut für Pharmazeutische Wissenschaften, Vladimir-Prelog-Weg 4, CH-8093, Zürich, Switzerland
| | - Silja Wessler
- Department of Molecular Biology, Division of Microbiology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria
| | - Steffen Backert
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058, Erlangen, Germany.,Institut für Medizinische Mikrobiologie, Otto-von-Guericke Universität Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany
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62
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Russell TM, Tang X, Goldstein JM, Bagarozzi D, Johnson BJB. The salt-sensitive structure and zinc inhibition of Borrelia burgdorferi protease BbHtrA. Mol Microbiol 2015; 99:586-96. [PMID: 26480895 DOI: 10.1111/mmi.13251] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2015] [Indexed: 11/28/2022]
Abstract
HtrA serine proteases are highly conserved and essential ATP-independent proteases with chaperone activity. Bacteria express a variable number of HtrA homologues that contribute to the virulence and pathogenicity of bacterial pathogens. Lyme disease spirochetes possess a single HtrA protease homologue, Borrelia burgdorferi HtrA (BbHtrA). Previous studies established that, like the human orthologue HtrA1, BbHtrA is proteolytically active against numerous extracellular proteins in vitro. In this study, we utilized size exclusion chromatography and blue native polyacrylamide gel electrophoresis (BN-PAGE) to demonstrate BbHtrA oligomeric structures that were substrate independent and salt sensitive. Examination of the influence of transition metals on the activity of BbHtrA revealed that this protease is inhibited by Zn(2+) > Cu(2+) > Mn(2+). Extending this analysis to two other HtrA proteases, E. coli DegP and HtrA1, revealed that all three HtrA proteases were reversibly inhibited by ZnCl2 at all micro molar concentrations examined. Commercial inhibitors for HtrA proteases are not available and physiologic HtrA inhibitors are unknown. Our observation of conserved zinc inhibition of HtrA proteases will facilitate structural and functional studies of additional members of this important class of proteases.
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Affiliation(s)
- Theresa M Russell
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Fort Collins, CO, USA
| | - Xiaoling Tang
- Division of Scientific Resources, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Atlanta, GA, USA
| | - Jason M Goldstein
- Division of Scientific Resources, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Atlanta, GA, USA
| | - Dennis Bagarozzi
- Division of Scientific Resources, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Atlanta, GA, USA
| | - Barbara J B Johnson
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Fort Collins, CO, USA
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63
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Abstract
The major class of integral proteins found in the outer membrane (OM) of E. coli and Salmonella adopt a β-barrel conformation (OMPs). OMPs are synthesized in the cytoplasm with a typical signal sequence at the amino terminus, which directs them to the secretion machinery (SecYEG) located in the inner membrane for translocation to the periplasm. Chaperones such as SurA, or DegP and Skp, escort these proteins across the aqueous periplasm protecting them from aggregation. The chaperones then deliver OMPs to a highly conserved outer membrane assembly site termed the Bam complex. In E. coli, the Bam complex is composed of an essential OMP, BamA, and four associated OM lipoproteins, BamBCDE, one of which, BamD, is also essential. Here we provide an overview of what we know about the process of OMP assembly and outline the various hypotheses that have been proposed to explain how proteins might be integrated into the asymmetric OM lipid bilayer in an environment that lacks obvious energy sources. In addition, we describe the envelope stress responses that ensure the fidelity of OM biogenesis and how factors, such as phage and certain toxins, have coopted this essential machine to gain entry into the cell.
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64
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Bodelón G, Marín E, Fernández LÁ. Analyzing the Role of Periplasmic Folding Factors in the Biogenesis of OMPs and Members of the Type V Secretion System. Methods Mol Biol 2015; 1329:77-110. [PMID: 26427678 DOI: 10.1007/978-1-4939-2871-2_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
The outer membrane (OM) of gram-negative bacteria is highly packed with OM proteins (OMPs) and the trafficking and assembly of OMPs in gram-negative bacteria is a subject of intense research. Structurally, OMPs vary in the number of β-strands and in the size and complexity of extra-membrane domains, with extreme examples being the members of the type V protein secretion system (T5SS), such as the autotransporter (AT) and intimin/invasin families of secreted proteins, in which a large extracellular "passenger" domain is linked to a β-barrel that inserts in the OM. Despite their structural and functional diversity, OMPs interact in the periplasm with a relatively small set of protein chaperones that facilitate their transport from the inner membrane (IM) to the β-barrel assembly machinery (BAM complex), preventing aggregation and assisting their folding in various aspects including disulfide bond formation. This chapter is focused on the periplasmic folding factors involved in the biogenesis of integral OMPs and members of T5SS in E. coli, which are used as a model system in this field. Background information on these periplasmic folding factors is provided along with genetic methods to generate conditional mutants that deplete these factors from E. coli and biochemical methods to analyze the folding, surface display, disulfide formation and oligomerization state of OMPs/T5SS in these mutants.
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Affiliation(s)
- Gustavo Bodelón
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain
| | - Elvira Marín
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain
| | - Luis Ángel Fernández
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain.
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Schubert A, Wrase R, Hilgenfeld R, Hansen G. Structures of DegQ from Legionella pneumophila Define Distinct ON and OFF States. J Mol Biol 2015. [PMID: 26205420 DOI: 10.1016/j.jmb.2015.06.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
HtrA (high-temperature requirement A) family proteins play important roles in protein-quality control processes in the bacterial periplasm. A common feature of all members of this family is their modular organization comprising a chymotrypsin-like protease domain and at least one PDZ (postsynaptic density of 95 kDa, disks large homolog 1 and zonula occludens 1) domain. All characterized HtrA proteins assemble into complex oligomers consisting of typically 3-24 monomers, which allow a tight regulation of proteolytic activity. Here, we provide evidence that the assembly of proteolytically active, higher-order complexes of DegQ from Legionella pneumophila is triggered by the binding of substrate-derived peptides. Crystal structures of inactive 3-mers and active 12-mers of DegQ reveal molecular details of elements of a conserved allosteric activation cascade that defines distinct protease ON and OFF states. Results from DegQ(Lp) variants harboring structure-based amino acid substitutions indicate that peptide binding to the PDZ1 domain is critical for proteolytic activity but not for the formation of higher-order oligomers. Combining structural, mutagenesis and biochemical data, we show that, in contrast to the proteolytic activity, the chaperone function of DegQ is not affected by the state of the activation cascade.
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Affiliation(s)
- Alexander Schubert
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Robert Wrase
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Rolf Hilgenfeld
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany; German Center of Infection Research (DZIF), Hamburg Lübeck Borstel Site, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Guido Hansen
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany.
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Glaza P, Osipiuk J, Wenta T, Zurawa-Janicka D, Jarzab M, Lesner A, Banecki B, Skorko-Glonek J, Joachimiak A, Lipinska B. Structural and Functional Analysis of Human HtrA3 Protease and Its Subdomains. PLoS One 2015; 10:e0131142. [PMID: 26110759 PMCID: PMC4481513 DOI: 10.1371/journal.pone.0131142] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 05/27/2015] [Indexed: 11/18/2022] Open
Abstract
Human HtrA3 protease, which induces mitochondria-mediated apoptosis, can be a tumor suppressor and a potential therapeutic target in the treatment of cancer. However, there is little information about its structure and biochemical properties. HtrA3 is composed of an N-terminal domain not required for proteolytic activity, a central serine protease domain and a C-terminal PDZ domain. HtrA3S, its short natural isoform, lacks the PDZ domain which is substituted by a stretch of 7 C-terminal amino acid residues, unique for this isoform. This paper presents the crystal structure of the HtrA3 protease domain together with the PDZ domain (ΔN-HtrA3), showing that the protein forms a trimer whose protease domains are similar to those of human HtrA1 and HtrA2. The ΔN-HtrA3 PDZ domains are placed in a position intermediate between that in the flat saucer-like HtrA1 SAXS structure and the compact pyramidal HtrA2 X-ray structure. The PDZ domain interacts closely with the LB loop of the protease domain in a way not found in other human HtrAs. ΔN-HtrA3 with the PDZ removed (ΔN-HtrA3-ΔPDZ) and an N-terminally truncated HtrA3S (ΔN-HtrA3S) were fully active at a wide range of temperatures and their substrate affinity was not impaired. This indicates that the PDZ domain is dispensable for HtrA3 activity. As determined by size exclusion chromatography, ΔN-HtrA3 formed stable trimers while both ΔN-HtrA3-ΔPDZ and ΔN-HtrA3S were monomeric. This suggests that the presence of the PDZ domain, unlike in HtrA1 and HtrA2, influences HtrA3 trimer formation. The unique C-terminal sequence of ΔN-HtrA3S appeared to have little effect on activity and oligomerization. Additionally, we examined the cleavage specificity of ΔN-HtrA3. Results reported in this paper provide new insights into the structure and function of ΔN-HtrA3, which seems to have a unique combination of features among human HtrA proteases.
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Affiliation(s)
- Przemyslaw Glaza
- Department of Biochemistry, Faculty of Biology, University of Gdansk, 80–308 Gdansk, Poland
| | - Jerzy Osipiuk
- Midwest Center for Structural Genomics, Argonne National Laboratory, Argonne, Illinois, IL 60439, United States of America
- Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, IL 60439, United States of America
| | - Tomasz Wenta
- Department of Biochemistry, Faculty of Biology, University of Gdansk, 80–308 Gdansk, Poland
| | - Dorota Zurawa-Janicka
- Department of Biochemistry, Faculty of Biology, University of Gdansk, 80–308 Gdansk, Poland
| | - Miroslaw Jarzab
- Department of Biochemistry, Faculty of Biology, University of Gdansk, 80–308 Gdansk, Poland
| | - Adam Lesner
- Department of Biochemistry, Faculty of Chemistry, University of Gdansk, 80–308 Gdansk, Poland
| | - Bogdan Banecki
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology of the University of Gdansk and the Medical University of Gdansk, 80–822 Gdansk, Poland
| | - Joanna Skorko-Glonek
- Department of Biochemistry, Faculty of Biology, University of Gdansk, 80–308 Gdansk, Poland
| | - Andrzej Joachimiak
- Midwest Center for Structural Genomics, Argonne National Laboratory, Argonne, Illinois, IL 60439, United States of America
- Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, IL 60439, United States of America
| | - Barbara Lipinska
- Department of Biochemistry, Faculty of Biology, University of Gdansk, 80–308 Gdansk, Poland
- * E-mail:
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Rai N, Ramaswamy A. Temperature dependent dynamics of DegP-trimer: A molecular dynamics study. Comput Struct Biotechnol J 2015; 13:329-38. [PMID: 25987966 PMCID: PMC4434178 DOI: 10.1016/j.csbj.2015.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/15/2015] [Accepted: 04/18/2015] [Indexed: 11/18/2022] Open
Abstract
DegP is a heat shock protein from high temperature requirement protease A family, which reacts to the environmental stress conditions in an ATP independent way. The objective of the present analysis emerged from the temperature dependent functional diversity of DegP between chaperonic and protease activities at temperatures below and above 28 °C, respectively. DegP is a multimeric protein and the minimal functional unit, DegP-trimer, is of great importance in understanding the DegP pathway. The structural aspects of DegP-trimer with respect to temperature variation have been studied using molecular dynamics simulations (for 100 ns) and principal component analysis to highlight the temperature dependent dynamics facilitating its functional diversity. The DegP-trimer revealed a pronounced dynamics at both 280 and 320 K, when compared to the dynamics observed at 300 K. The LA loop is identified as the highly flexible region during dynamics and at extreme temperatures, the residues 46–80 of LA loop express a flip towards right (at 280) and left ( at 320 K) with respect to the fixed β-sheet connecting the LA loop of protease for which Phe46 acts as one of the key residues. Such dynamics of LA loop facilitates inter-monomeric interaction with the PDZ1 domain of the neighbouring monomer and explains its active participation when DegP exists as trimer. Hence, the LA loop mediated dynamics of DegP-trimer is expected to provide further insight into the temperature dependent dynamics of DegP towards the understanding of its assembly and functional diversity in the presence of substrate.
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Affiliation(s)
- Nivedita Rai
- Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry 605014, India
| | - Amutha Ramaswamy
- Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry 605014, India
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de Regt AK, Kim S, Sohn J, Grant RA, Baker TA, Sauer RT. A conserved activation cluster is required for allosteric communication in HtrA-family proteases. Structure 2015; 23:517-526. [PMID: 25703375 DOI: 10.1016/j.str.2015.01.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 12/16/2022]
Abstract
In E. coli, outer-membrane stress causes a transcriptional response through a signaling cascade initiated by DegS cleavage of a transmembrane antisigma factor. Each subunit of DegS, an HtrA-family protease, contains a protease domain and a PDZ domain. The trimeric protease domain is autoinhibited by the unliganded PDZ domains. Allosteric activation requires binding of unassembled outer-membrane proteins (OMPs) to the PDZ domains and protein substrate binding. Here, we identify a set of DegS residues that cluster together at subunit-subunit interfaces in the trimer, link the active sites and substrate binding sites, and are crucial for stabilizing the active enzyme conformation in response to OMP signaling. These residues are conserved across the HtrA-protease family, including orthologs linked to human disease, supporting a common mechanism of allosteric activation. Indeed, mutation of residues at homologous positions in the DegP quality-control protease also eliminates allosteric activation.
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Affiliation(s)
- Anna K de Regt
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Seokhee Kim
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Jungsan Sohn
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Robert A Grant
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Tania A Baker
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Robert T Sauer
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA.
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Wang S, Dong ZY, Yan YB. Formation of high-order oligomers by a hyperthemostable Fe-superoxide dismutase (tcSOD). PLoS One 2014; 9:e109657. [PMID: 25313557 PMCID: PMC4196948 DOI: 10.1371/journal.pone.0109657] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 09/02/2014] [Indexed: 12/20/2022] Open
Abstract
Hyperthermostable proteins are highly resistant to various extreme conditions. Many factors have been proposed to contribute to their ultrahigh structural stability. Some thermostable proteins have larger oligomeric size when compared to their mesophilic homologues. The formation of compact oligomers can minimize the solvent accessible surface area and increase the changes of Gibbs free energy for unfolding. Similar to mesophilic proteins, hyperthermostable proteins also face the problem of unproductive aggregation. In this research, we investigated the role of high-order oligomerization in the fight against aggregation by a hyperthermostable superoxide dismutase identified from Tengchong, China (tcSOD). Besides the predominant tetramers, tcSOD could also form active high-order oligomers containing at least eight subunits. The dynamic equilibrium between tetramers and high-order oligomers was not significantly affected by pH, salt concentration or moderate temperature. The secondary and tertiary structures of tcSOD remained unchanged during heating, while cross-linking experiments showed that there were conformational changes or structural fluctuations at high temperatures. Mutational analysis indicated that the last helix at the C-terminus was involved in the formation of high-order oligomers, probably via domain swapping. Based on these results, we proposed that the reversible conversion between the active tetramers and high-order oligomers might provide a buffering system for tcSOD to fight against the irreversible protein aggregation pathway. The formation of active high-order oligomers not only increases the energy barrier between the native state and unfolded/aggregated state, but also provides the enzyme the ability to reproduce the predominant oligomers from the active high-order oligomers.
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Affiliation(s)
- Sha Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhi-Yang Dong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- * E-mail: (YBY); (ZYD)
| | - Yong-Bin Yan
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China
- * E-mail: (YBY); (ZYD)
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70
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Kim S, Sauer RT. Distinct regulatory mechanisms balance DegP proteolysis to maintain cellular fitness during heat stress. Genes Dev 2014; 28:902-11. [PMID: 24736846 PMCID: PMC4003281 DOI: 10.1101/gad.238394.114] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Intracellular proteases combat proteotoxic stress by degrading damaged proteins, but their activity must be controlled to maintain cellular fitness. DegP is a conserved periplasmic protease essential for E. coli growth at high temperatures. Kim and Sauer investigate how allosteric activation and polyhedral cage formation contribute to DegP function and cellular fitness. The results suggest that allosteric control of active and inactive conformations is the primary mechanism regulating DegP proteolysis and cellular fitness, with cage assembly providing an additional layer of protection against excessive protease activity. Intracellular proteases combat proteotoxic stress by degrading damaged proteins, but their activity must be carefully controlled to maintain cellular fitness. The activity of Escherichia coli DegP, a highly conserved periplasmic protease, is regulated by substrate-dependent allosteric transformations between inactive and active trimer conformations and by the formation of polyhedral cages that confine the active sites within a proteolytic chamber. Here, we investigate how these distinct control mechanisms contribute to bacterial fitness under heat stress. We found that mutations that increase or decrease the equilibrium population of active DegP trimers reduce high-temperature fitness, that a mutation that blocks cage formation causes a mild fitness decrease, and that combining mutations that stabilize active DegP and block cage formation generates a lethal rogue protease. This lethality is suppressed by an extragenic mutation that prevents covalent attachment of an abundant outer-membrane lipoprotein to peptidoglycan and makes this protein an inhibitor of the rogue protease. Lethality is also suppressed by intragenic mutations that stabilize inactive DegP trimers. In combination, our results suggest that allosteric control of active and inactive conformations is the primary mechanism that regulates DegP proteolysis and fitness, with cage formation providing an additional layer of cellular protection against excessive protease activity.
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Affiliation(s)
- Seokhee Kim
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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71
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Thermal-triggerd proteinquake leads to disassembly of DegP hexamer as an imperative activation step. Sci Rep 2014; 4:4834. [PMID: 24776652 PMCID: PMC4003476 DOI: 10.1038/srep04834] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 04/11/2014] [Indexed: 11/23/2022] Open
Abstract
The Escherichia coli DegP has been reported to function both as molecular chaperone and protease for the quality control of outer membrane protein biogenesis. Activation of the inactive DegP hexamers was believed to occur via their disassembly into trimeric units and subsequent reassembly into larger oligomers (12-mers and 24-mers). Here, we analyzed the thermal stability and the unfolding dynamics of the different secondary structure components of the DegP hexamers using Fourier transform infrared spectroscopy and temperature-jump nanosecond time-resolved IR difference absorbance spectroscopy. We found that the interfacial secondary structure components possess a degreed thermal stability, with the disassembly of the DegP hexamers follows a “proteinquake” manner, such that the fully exposed parts of the interfacial β-sheets serving as the temperature sensor and epicenter to drive the sequential unfolding/disassembly process that finishes within about 134 ns at room temperature.
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72
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Sharma S, Jadli M, Singh A, Arora K, Malhotra P. A secretory multifunctional serine protease, DegP of Plasmodium falciparum, plays an important role in thermo-oxidative stress, parasite growth and development. FEBS J 2014; 281:1679-99. [PMID: 24494818 DOI: 10.1111/febs.12732] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/27/2013] [Accepted: 01/23/2014] [Indexed: 12/12/2022]
Abstract
UNLABELLED Plasmodium falciparum heat shock proteins and proteases are known for their indispensable roles in parasite virulence and survival in the host cell. They neutralize various host-derived stress responses that are deleterious for parasite growth and invasion. We report identification and functional characterization of the first DegP from an apicomplexan (P. falciparum). To determine the molecular identity and functions of the parasite-encoded DegP, we complemented the Escherichia coli degP null mutant with a putative PfdegP gene, and the results showed that PfDegP complements the growth defect of the temperature sensitive DegP-deficient mutant and imparts resistance to non-permissive temperatures and oxidative stress. Molecular interaction studies showed that PfDegP exists as a complex with parasite-encoded heat shock protein 70, iron superoxide dismutase and enolase. DegP expression is significantly induced in parasite culture upon heat shock/oxidative stress. Our data suggest that the PfDegP protein may play a role in the growth and development of P. falciparum through its ability to confer protection against thermal/oxidative stress. Antibody against DegP showed anti-plasmodial activity against blood-stage parasites in vitro, suggesting that PfDegP and its associated complex may be a potential focus for new anti-malarial therapies. STRUCTURED DIGITAL ABSTRACT ●PfDegP physically interacts with PfHsp70 and PfEno by anti-bait co-immunoprecipitation (View interaction) ●PfDegP physically interacts with PfEno, PfSod, PfOat, PfHsp70, PfLDH and PfGpi by anti-bait co-immunoprecipitation (View interaction) ●PfHsp-70 and PfDegP co-localize by fluorescence microscopy (View interaction) ●PfDegP physically interacts with PfOat, PfHsp70, PfEno, PfSod, PfGpi and PfLDH by surface plasmon resonance (View interaction) ●PfEno and PfDegP co-localize by fluorescence microscopy (View interaction) ●PfDegP and PfHsp70 co-localize by co-sedimentation through density gradient (View interaction).
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Affiliation(s)
- Shweta Sharma
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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73
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Ge X, Wang R, Ma J, Liu Y, Ezemaduka AN, Chen PR, Fu X, Chang Z. DegP primarily functions as a protease for the biogenesis of β-barrel outer membrane proteins in the Gram-negative bacterium Escherichia coli. FEBS J 2014; 281:1226-40. [PMID: 24373465 DOI: 10.1111/febs.12701] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 12/16/2013] [Accepted: 12/17/2013] [Indexed: 12/31/2022]
Abstract
DegP (also designated as HtrA) and its homologs are found in prokaryotic cells and such eukaryotic organelles as mitochondria and chloroplasts. DegP has been found to be essential for the growth of Gram-negative bacteria under heat shock conditions and arguably considered to possess both protease and chaperone activities. The function of DegP has not been clearly defined. Using genetically incorporated non-natural amino acids as photo-crosslinkers, here we identified the β-barrel outer membrane proteins (OMPs) as the major natural substrates of DegP in Escherichia coli cells. We also demonstrated that DegP primarily functions as a protease, at both low and high temperatures, to eliminate unfolded OMPs, with hardly any appreciable chaperone activity in cells. We also found that the toxic and cell membrane-damaging misfolded OMPs would accumulate in DegP-lacking cells cultured under heat shock conditions. Together, our study defines the primary function of DegP in OMP biogenesis and offers a mechanistic insight into the essentiality of DegP for cell growth under heat shock conditions.
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Affiliation(s)
- Xi Ge
- State Key Laboratory of Protein and Plant Gene Research and School of Life Sciences, Peking University, China
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Thompson NJ, Merdanovic M, Ehrmann M, van Duijn E, Heck AJR. Substrate occupancy at the onset of oligomeric transitions of DegP. Structure 2013; 22:281-90. [PMID: 24373769 DOI: 10.1016/j.str.2013.11.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 11/14/2013] [Accepted: 11/20/2013] [Indexed: 01/06/2023]
Abstract
The protease-chaperone DegP undergoes secondary through quaternary structural changes, regulating function and preventing indiscriminate proteolysis. Several structures of DegP oligomers have been observed, including the resting state 6-mer and the 12-mer and 24-mer active states. However, the precise events of the transition between the resting and active states still need to be elucidated. We used native mass spectrometry to demonstrate that binding of multiple substrate-mimicking peptide ligands to the DegP resting state occurs prior to the transition to an active conformation. This transition occurred at a 6-mer occupancy of 40% for each peptide ligand. We observed ligand-specific 9-mer formation with a maximum load of 9 peptides, whereas other substrates led to 12-mers accommodating 24 peptides. Based on these data, we present a model for the initial steps of substrate-induced transitions from the resting to active states of DegP.
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Affiliation(s)
- Natalie J Thompson
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Melisa Merdanovic
- Faculty of Biology, Center for Medical Biotechnology, University Duisburg-Essen, 45117 Essen, Germany
| | - Michael Ehrmann
- Faculty of Biology, Center for Medical Biotechnology, University Duisburg-Essen, 45117 Essen, Germany; School of Biosciences, Cardiff University, Cardiff CF10 3US, UK
| | - Esther van Duijn
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, the Netherlands.
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75
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Folding mechanisms of periplasmic proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1517-28. [PMID: 24239929 DOI: 10.1016/j.bbamcr.2013.10.014] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 10/11/2013] [Accepted: 10/16/2013] [Indexed: 01/03/2023]
Abstract
More than one fifth of the proteins encoded by the genome of Escherichia coli are destined to the bacterial cell envelope. Over the past 20years, the mechanisms by which envelope proteins reach their three-dimensional structure have been intensively studied, leading to the discovery of an intricate network of periplasmic folding helpers whose members have distinct but complementary roles. For instance, the correct assembly of ß-barrel proteins containing disulfide bonds depends both on chaperones like SurA and Skp for transport across the periplasm and on protein folding catalysts like DsbA and DsbC for disulfide bond formation. In this review, we provide an overview of the current knowledge about the complex network of protein folding helpers present in the periplasm of E. coli and highlight the questions that remain unsolved. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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76
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Proteolytic activation of Chlamydia trachomatis HTRA is mediated by PDZ1 domain interactions with protease domain loops L3 and LC and beta strand β5. Cell Mol Biol Lett 2013; 18:522-37. [PMID: 24036669 PMCID: PMC6275972 DOI: 10.2478/s11658-013-0103-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 09/09/2013] [Indexed: 01/19/2023] Open
Abstract
Chlamydia trachomatis is a bacterial pathogen responsible for one of the most prevalent sexually transmitted infections worldwide. Its unique development cycle has limited our understanding of its pathogenic mechanisms. However, CtHtrA has recently been identified as a potential C. trachomatis virulence factor. CtHtrA is a tightly regulated quality control protein with a monomeric structural unit comprised of a chymotrypsin-like protease domain and two PDZ domains. Activation of proteolytic activity relies on the C-terminus of the substrate allosterically binding to the PDZ1 domain, which triggers subsequent conformational change and oligomerization of the protein into 24-mers enabling proteolysis. This activation is mediated by a cascade of precise structural arrangements, but the specific CtHtrA residues and structural elements required to facilitate activation are unknown. Using in vitro analysis guided by homology modeling, we show that the mutation of residues Arg362 and Arg224, predicted to disrupt the interaction between the CtHtrA PDZ1 domain and loop L3, and between loop L3 and loop LD, respectively, are critical for the activation of proteolytic activity. We also demonstrate that mutation to residues Arg299 and Lys160, predicted to disrupt PDZ1 domain interactions with protease loop LC and strand β5, are also able to influence proteolysis, implying their involvement in the CtHtrA mechanism of activation. This is the first investigation of protease loop LC and strand β5 with respect to their potential interactions with the PDZ1 domain. Given their high level of conservation in bacterial HtrA, these structural elements may be equally significant in the activation mechanism of DegP and other HtrA family members.
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Solov'eva TF, Novikova OD, Portnyagina OY. Biogenesis of β-barrel integral proteins of bacterial outer membrane. BIOCHEMISTRY (MOSCOW) 2013; 77:1221-36. [PMID: 23240560 DOI: 10.1134/s0006297912110016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Gram-negative bacteria are enveloped by two membranes, the inner (cytoplasmic) (CM) and the outer (OM). The majority of integral outer membrane proteins are arranged in β-barrels of cylindrical shape composed of amphipathic antiparallel β-strands. In bacteria, β-barrel proteins function as water-filled pores, active transporters, enzymes, receptors, and structural proteins. Proteins of bacterial OM are synthesized in the cytoplasm as unfolded polypeptides with an N-terminal sequence that marks them for transport across the CM. Precursors of membrane proteins move through the aqueous medium of the cytosol and periplasm under the protection of chaperones (SecB, Skp, SurA, and DegP), then cross the CM via the Sec system composed of a polypeptide-conducting channel (SecYEG) and ATPase (SecA), the latter providing the energy for the translocation of the pre-protein. Pre-protein folding and incorporation in the OM require the participation of the Bam-complex, probably without the use of energy. This review summarizes current data on the biogenesis of the β-barrel proteins of bacterial OM. Data on the structure of the proteins included in the multicomponent system for delivery of the OM proteins to their destination in the cell and on their complexes with partners, including pre-proteins, are presented. Molecular models constructed on the basis of structural, genetic, and biochemical studies that describe the mechanisms of β-barrel protein assembly by this molecular transport machinery are also considered.
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Affiliation(s)
- T F Solov'eva
- Elyakov Pacific Institute of Bioorganic Chemistry, Russian Academy of Sciences, Vladivostok, 690022, Russia.
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78
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Chaganti LK, Kuppili RR, Bose K. Intricate structural coordination and domain plasticity regulate activity of serine protease HtrA2. FASEB J 2013; 27:3054-66. [DOI: 10.1096/fj.13-227256] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Lalith K. Chaganti
- Advanced Centre for Treatment, Research, and Education in Cancer (ACTREC)Tata Memorial CentreNavi MumbaiIndia
| | - Raja Reddy Kuppili
- Advanced Centre for Treatment, Research, and Education in Cancer (ACTREC)Tata Memorial CentreNavi MumbaiIndia
| | - Kakoli Bose
- Advanced Centre for Treatment, Research, and Education in Cancer (ACTREC)Tata Memorial CentreNavi MumbaiIndia
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79
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Bodelón G, Palomino C, Fernández LÁ. Immunoglobulin domains inEscherichia coliand other enterobacteria: from pathogenesis to applications in antibody technologies. FEMS Microbiol Rev 2013; 37:204-50. [DOI: 10.1111/j.1574-6976.2012.00347.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 06/07/2012] [Accepted: 06/14/2012] [Indexed: 11/28/2022] Open
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80
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Hansen G, Hilgenfeld R. Architecture and regulation of HtrA-family proteins involved in protein quality control and stress response. Cell Mol Life Sci 2013; 70:761-75. [PMID: 22806565 PMCID: PMC11113883 DOI: 10.1007/s00018-012-1076-4] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 06/24/2012] [Accepted: 06/26/2012] [Indexed: 12/22/2022]
Abstract
Protein quality control is vital for all living cells and sophisticated molecular mechanisms have evolved to prevent the excessive accumulation of unfolded proteins. High-temperature requirement A (HtrA) proteases have been identified as important ATP-independent quality-control factors in most species. HtrA proteins harbor a serine-protease domain and at least one peptide-binding PDZ domain to ensure efficient removal of misfolded or damaged proteins. One distinctive property of HtrAs is their ability to assemble into complex oligomers. Whereas all examined HtrAs are capable of forming pyramidal 3-mers, higher-order complexes consisting of up to 24 molecules have been reported. Tight control of chaperone and protease function is of pivotal importance in preventing deleterious HtrA-protease activity. In recent years, structural biology provided detailed insights into the molecular basis of the regulatory mechanisms, which include unique intramolecular allosteric signaling cascades and the dynamic switching of oligomeric states of HtrA proteins. Based on these results, functional models for many family members have been developed. The HtrA protein family represents a remarkable example of how structural and functional diversity is attained from the assembly of simple molecular building blocks.
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Affiliation(s)
- Guido Hansen
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, 23538, Lübeck, Germany.
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81
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Dutta A, Katarkar A, Chaudhuri K. In-silico structural and functional characterization of a V. cholerae O395 hypothetical protein containing a PDZ1 and an uncommon protease domain. PLoS One 2013; 8:e56725. [PMID: 23441214 PMCID: PMC3575494 DOI: 10.1371/journal.pone.0056725] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 01/14/2013] [Indexed: 11/18/2022] Open
Abstract
Vibrio cholerae, the causative agent of epidemic cholera, has been a constant source of concern for decades. It has constantly evolved itself in order to survive the changing environment. Acquisition of new genetic elements through genomic islands has played a major role in its evolutionary process. In this present study a hypothetical protein was identified which was present in one of the predicted genomic island regions of the large chromosome of V. cholerae O395 showing a strong homology with a conserved phage encoded protein. In-silico physicochemical analysis revealed that the hypothetical protein was a periplasmic protein. Homology modeling study indicated that the hypothetical protein was an unconventional and atypical serine protease belonging to HtrA protein family. The predicted 3D-model of the hypothetical protein revealed a catalytic centre serine utilizing a single catalytic residue for proteolysis. The predicted catalytic triad may help to deduce the active site for the recruitment of the substrate for proteolysis. The active site arrangements of this predicted serine protease homologue with atypical catalytic triad is expected to allow these proteases to work in different environments of the host.
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Affiliation(s)
- Avirup Dutta
- CSIR-SRF, Molecular and Human Genetics Division, CSIR - Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Atul Katarkar
- ICMR-SRF, Molecular and Human Genetics Division, CSIR - Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Keya Chaudhuri
- Chief Scientist, Molecular and Human Genetics Division, and Head Academic Affairs Division, CSIR - Indian Institute of Chemical Biology, Kolkata, West Bengal, India
- * E-mail:
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82
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Shan X, Sun W, Fan H, Jia M, Gao F, Gong W. Expression, purification, crystallization and preliminary X-ray diffraction analysis of Arabidopsis thaliana Deg8. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:69-72. [PMID: 23295491 DOI: 10.1107/s1744309112048774] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 11/27/2012] [Indexed: 11/10/2022]
Abstract
Arabidopsis thaliana Deg8, an ATP-independent serine endopeptidase, is involved in the repair of photosystem II (PSII), specifically the degradation of the photo-damaged PSII reaction centre D1 protein. To understand the molecular mechanism underlying the participation of Deg8 in the degradation of the photo-damaged D1 protein, the structure of Deg8 is needed. Until recently, however, no structure of Deg8 had been solved. In this study, Deg8 from A. thaliana was cloned, overexpressed and purified in Escherichia coli. Crystallization was performed at 277 K using tribasic sodium citrate as the precipitant and the crystals diffracted to 2.0 Å resolution, belonging to space group C2 with unit-cell parameters a = 129.5, b = 124.2, c = 93.3 Å, α = γ = 90, β = 132.4°. Assuming one trimer in the asymmetric unit, the Matthews coefficient and the solvent content were calculated to be 2.35 Å(3) Da(-1) and 47.6%, respectively.
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Affiliation(s)
- Xiaoyue Shan
- Laboratory of Noncoding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, People's Republic of China
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83
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Cassone M, Gagne AL, Spruce LA, Seeholzer SH, Sebert ME. The HtrA protease from Streptococcus pneumoniae digests both denatured proteins and the competence-stimulating peptide. J Biol Chem 2012; 287:38449-59. [PMID: 23012372 DOI: 10.1074/jbc.m112.391482] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The HtrA protease of Streptococcus pneumoniae functions both in a general stress response role and as an error sensor that specifically represses genetic competence when the overall level of biosynthetic errors in cellular proteins is low. However, the mechanism through which HtrA inhibits development of competence has been unknown. We found that HtrA digested the pneumococcal competence-stimulating peptide (CSP) and constituted the primary extracytoplasmic CSP-degrading activity in cultures of S. pneumoniae. Mass spectrometry demonstrated that cleavage predominantly followed residue Phe-8 of the CSP-1 isoform of the peptide within its central hydrophobic patch, and in competition assays, both CSP-1 and CSP-2 interacted with HtrA with similar efficiencies. More generally, analysis of β-casein digestion and of digestion within HtrA itself revealed a preference for substrates with non-polar residues at the P1 site. Consistent with a specificity for exposed hydrophobic residues, competition from native BSA only weakly inhibited digestion of CSP, but denaturation converted BSA into a strong competitive inhibitor of such proteolysis. Together these findings support a model in which digestion of CSP by HtrA is reduced in the presence of other unfolded proteins that serve as alternative targets for degradation. Such competition may provide a mechanism by which HtrA functions in a quality control capacity to monitor the frequency of biosynthetic errors that result in protein misfolding.
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Affiliation(s)
- Marco Cassone
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
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84
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Sun R, Fan H, Gao F, Lin Y, Zhang L, Gong W, Liu L. Crystal structure of Arabidopsis Deg2 protein reveals an internal PDZ ligand locking the hexameric resting state. J Biol Chem 2012; 287:37564-9. [PMID: 22961982 PMCID: PMC3481350 DOI: 10.1074/jbc.m112.394585] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Eukaryotic organelles have developed elaborate protein quality control systems to ensure their normal activity, among which Deg/HtrA proteases play an essential role. Plant Deg2 protease is a homologue of prokaryotic DegQ/DegP proteases and is located in the chloroplast stroma, where its proteolytic activity is required to maintain the efficiency of photosynthetic machinery during stress. Here, we demonstrate that Deg2 exhibits dual protease-chaperone activities, and we present the hexameric structure of Deg2 complexed with co-purified peptides. The structure shows that Deg2 contains a unique second PDZ domain (PDZ2) following a conventional PDZ domain (PDZ1), with PDZ2 orchestrating the cage assembly of Deg2. We discovered a conserved internal ligand for PDZ2 that mediates hexamer formation and thus locks the protease in the resting state. These findings provide insight into the diverse modes of PDZ domain-mediated regulation of Deg proteases.
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Affiliation(s)
- Renhua Sun
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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85
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Denoncin K, Schwalm J, Vertommen D, Silhavy TJ, Collet JF. Dissecting the Escherichia coli periplasmic chaperone network using differential proteomics. Proteomics 2012; 12:1391-401. [PMID: 22589188 DOI: 10.1002/pmic.201100633] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
β-Barrel proteins, or outer membrane proteins (OMPs), perform many essential functions in Gram-negative bacteria, but questions remain about the mechanism by which they are assembled into the outer membrane (OM). In Escherichia coli, β-barrels are escorted across the periplasm by chaperones, most notably SurA and Skp. However, the contributions of these two chaperones to the assembly of the OM proteome remained unclear. We used differential proteomics to determine how the elimination of Skp and SurA affects the assembly of many OMPs. We have shown that removal of Skp has no impact on the levels of the 63 identified OM proteins. However, depletion of SurA in the skp strain has a marked impact on the OM proteome, diminishing the levels of almost all β-barrel proteins. Our results are consistent with a model in which SurA plays a primary chaperone role in E. coli. Furthermore, they suggest that while no OMPs prefer the Skp chaperone pathway in wild-type cells, most can use Skp efficiently when SurA is absent. Our data, which provide a unique glimpse into the protein content of the nonviable surA skp mutant, clarify the roles of the periplasmic chaperones in E. coli.
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Affiliation(s)
- Katleen Denoncin
- WELBIO (Walloon excellence in life sciences and biotechnology).,de Duve Institute, Université catholique de Louvain, B-1200 Brussels, Belgium
| | - Jaclyn Schwalm
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, 9 USA
| | - Didier Vertommen
- de Duve Institute, Université catholique de Louvain, B-1200 Brussels, Belgium
| | - Thomas J Silhavy
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, 9 USA
| | - Jean-Francois Collet
- WELBIO (Walloon excellence in life sciences and biotechnology).,de Duve Institute, Université catholique de Louvain, B-1200 Brussels, Belgium
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86
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Xue Y, Chowdhury S, Liu X, Akiyama Y, Ellman J, Ha Y. Conformational change in rhomboid protease GlpG induced by inhibitor binding to its S' subsites. Biochemistry 2012; 51:3723-31. [PMID: 22515733 DOI: 10.1021/bi300368b] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rhomboid protease conducts proteolysis inside the hydrophobic environment of the membrane. The conformational flexibility of the protease is essential for the enzyme mechanism, but the nature of this flexibility is not completely understood. Here we describe the crystal structure of rhomboid protease GlpG in complex with a phosphonofluoridate inhibitor, which is covalently bonded to the catalytic serine and extends into the S' side of the substrate binding cleft. Inhibitor binding causes subtle but extensive changes in the membrane protease. Many transmembrane helices tilt and shift positions, and the gap between S2 and S5 is slightly widened so that the inhibitor can bind between them. The side chain of Phe-245 from a loop (L5) that acts as a cap rotates and uncovers the opening of the substrate binding cleft to the lipid bilayer. A concurrent turn of the polypeptide backbone at Phe-245 moves the rest of the cap and exposes the catalytic serine to the aqueous solution. This study, together with earlier crystallographic investigation of smaller inhibitors, suggests a simple model for explaining substrate binding to rhomboid protease.
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Affiliation(s)
- Yi Xue
- Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06520, USA
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87
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Cage assembly of DegP protease is not required for substrate-dependent regulation of proteolytic activity or high-temperature cell survival. Proc Natl Acad Sci U S A 2012; 109:7263-8. [PMID: 22529381 DOI: 10.1073/pnas.1204791109] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
DegP, a member of the highly conserved HtrA family, performs quality-control degradation of misfolded proteins in the periplasm of gram-negative bacteria and is required for high-temperature survival of Escherichia coli. Substrate binding transforms DegP from an inactive oligomer containing two trimers into active polyhedral cages, typically containing four or eight trimers. Although these observations suggest a causal connection, we show that cage assembly and proteolytic activation can be uncoupled. Indeed, DegP variants that remain trimeric, hexameric, or dodecameric in the presence or absence of substrate still display robust and positively cooperative substrate degradation in vitro and, most importantly, sustain high-temperature bacterial growth as well as the wild-type enzyme. Our results support a model in which substrate binding converts inactive trimers into proteolytically active trimers, and simultaneously leads to cage assembly by enhancing binding of PDZ1 domains in one trimer to PDZ2' domains in neighboring trimers. Thus, both processes depend on substrate binding, but they can be uncoupled without loss of biological function. We discuss potential coupling mechanisms and why cage formation may have evolved if it is not required for DegP proteolysis.
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88
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Genetic analysis of 15 protein folding factors and proteases of the Escherichia coli cell envelope. J Bacteriol 2012; 194:3225-33. [PMID: 22505681 DOI: 10.1128/jb.00221-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Each cell hosts thousands of proteins that vary greatly in abundance, structure, and chemical properties. To ensure that all proteins are biologically active and properly localized, efficient quality control systems have evolved. While the structure, function, and regulation of some individual protein folding factors and proteases were resolved up to atomic resolution, others remain poorly characterized. In addition, little is known about which factors are required for viability under specific stress conditions. We therefore determined the physiological implications of 15 factors of the E. coli cell envelope by an integrated genetic approach comprising phenotypic analyses. Our data indicate that surA and tsp null mutations are a lethal combination in rich medium, that surA dsbA and surA dsbC double mutants are temperature sensitive, and that surA ptrA, surA yfgC, dsbA fkpA, degP tsp, degP ppiD, tsp ppiD, and degP dsbA double mutants are temperature sensitive in rich medium containing 0.5 M NaCl, while degP dsbA, degP yfgC, tsp ydgD, and degP tsp double mutants do not grow in the presence of SDS/EDTA. Furthermore, we show that in degP dsbA, degP tsp, and degP yfgC double mutants a subpopulation of LamB exists as unfolded monomers. In addition, dsbA null mutants expressed lower levels of the outer membrane proteins LptD, LamB, FhuA, and OmpW while FhuA levels were reduced in surA single and degP ppiD double mutants. Lower FhuA levels in degP ppiD strains depend on Tsp, since in a tsp degP ppiD triple mutant FhuA levels are restored.
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89
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Reversal of the ΔdegP phenotypes by a novel rpoE allele of Escherichia coli. PLoS One 2012; 7:e33979. [PMID: 22439016 PMCID: PMC3306311 DOI: 10.1371/journal.pone.0033979] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 02/20/2012] [Indexed: 11/20/2022] Open
Abstract
RseA sequesters RpoE (σE) to the inner membrane of Escherichia coli when envelope stress is low. Elevated envelope stress triggers RseA cleavage by the sequential action of two membrane proteases, DegS and RseP, releasing σE to activate an envelope stress reducing pathway. Revertants of a ΔdegP ΔbamB strain, which fails to grow at 37°C due to high envelope stress, harbored mutations in the rseA and rpoE genes. Null and missense rseA mutations constitutively hyper-activated the σE regulon and significantly reduced the major outer membrane protein (OMP) levels. In contrast, a novel rpoE allele, rpoE3, resulting from the partial duplication of the rpoE gene, increased σE levels greater than that seen in the rseA mutant background but did not reduce OMP levels. A σE-dependent RybB::LacZ construct showed only a weak activation of the σE pathway by rpoE3. Despite this, rpoE3 fully reversed the growth and envelope vesiculation phenotypes of ΔdegP. Interestingly, rpoE3 also brought down the modestly activated Cpx envelope stress pathway in the ΔdegP strain to the wild type level, showing the complementary nature of the σE and Cpx pathways. Through employing a labile mutant periplasmic protein, AcrAL222Q, it was determined that the rpoE3 mutation overcomes the ΔdegP phenotypes, in part, by activating a σE-dependent proteolytic pathway. Our data suggest that a reduction in the OMP levels is not intrinsic to the σE-mediated mechanism of lowering envelope stress. They also suggest that under extreme envelope stress, a tight homeostasis loop between RseA and σE may partly be responsible for cell death, and this loop can be broken by mutations that either lower RseA activity or increase σE levels.
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90
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Truscott KN, Bezawork-Geleta A, Dougan DA. Unfolded protein responses in bacteria and mitochondria: a central role for the ClpXP machine. IUBMB Life 2012; 63:955-63. [PMID: 22031494 DOI: 10.1002/iub.526] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In the crowded environment of a cell, the protein quality control machinery, such as molecular chaperones and proteases, maintains a population of folded and hence functional proteins. The accumulation of unfolded proteins in a cell is particularly harmful as it not only reduces the concentration of active proteins but also overburdens the protein quality control machinery, which in turn, can lead to a significant increase in nonproductive folding and protein aggregation. To circumvent this problem, cells use heat shock and unfolded protein stress response pathways, which essentially sense the change to protein homeostasis upregulating protein quality control factors that act to restore the balance. Interestingly, several stress response pathways are proteolytically controlled. In this review, we provide a brief summary of targeted protein degradation by AAA+ proteases and focus on the role of ClpXP proteases, particularly in the signaling pathway of the Escherichia coli extracellular stress response and the mitochondrial unfolded protein response.
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Affiliation(s)
- Kaye N Truscott
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia.
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91
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Zienkiewicz M, Ferenc A, Wasilewska W, Romanowska E. High light stimulates Deg1-dependent cleavage of the minor LHCII antenna proteins CP26 and CP29 and the PsbS protein in Arabidopsis thaliana. PLANTA 2012; 235:279-288. [PMID: 21877139 DOI: 10.1007/s00425-011-1505-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 08/10/2011] [Indexed: 05/31/2023]
Abstract
The chloroplast Deg1 protein performs proteolytic cleavage of the photodamaged D1 protein of the photosystem II (PSII) reaction center, PSII extrinsic subunit PsbO and the soluble electron carrier plastocyanin. Using biochemical, immunological and mass spectrometry approaches we showed that the heterogeneously expressed Deg1 protease from Arabidopsis thaliana can be responsible for the degradation of the monomeric light-harvesting complex antenna subunits of PSII (LHCII), CP26 and CP29, as well as PSII-associated PsbS (CP22/NPQ4) protein. The results may indicate that cytochrome b (6) protein and two previously unknown thylakoid proteins, Ptac16 and an 18.3-kDa protein, may be the substrates for Deg1. The interaction of Deg1 with the PsbS protein and the minor LHCII subunits implies its involvement in the regulation of both excess energy dissipation and state transition adaptation processes.
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Affiliation(s)
- Maksymilian Zienkiewicz
- Department of Molecular Plant Physiology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
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92
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Malet H, Canellas F, Sawa J, Yan J, Thalassinos K, Ehrmann M, Clausen T, Saibil HR. Newly folded substrates inside the molecular cage of the HtrA chaperone DegQ. Nat Struct Mol Biol 2012; 19:152-7. [PMID: 22245966 PMCID: PMC3272482 DOI: 10.1038/nsmb.2210] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 11/14/2011] [Indexed: 11/08/2022]
Abstract
The HtrA protein family combines chaperone and protease activities and is essential for protein quality control in many organisms. Whereas the mechanisms underlying the proteolytic function of HtrA proteins are well characterized, their chaperone activity remains poorly understood. Here we describe cryo-EM structures of Escherichia coli DegQ in its 12- and 24-mer states in complex with model substrates, providing a structural model of HtrA chaperone action. Up to six lysozyme substrates bind inside the DegQ 12-mer cage and are visualized in a close-to-native state. An asymmetric reconstruction reveals the binding of a well-ordered lysozyme to four DegQ protomers. DegQ PDZ domains are located adjacent to substrate density and their presence is required for chaperone activity. The substrate-interacting regions appear conserved in 12- and 24-mer cages, suggesting a common mechanism of chaperone function.
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Affiliation(s)
- Hélène Malet
- Institute of Structural and Molecular Biology, Crystallography, Birkbeck College, London, UK
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93
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Bai XC, Pan XJ, Wang XJ, Ye YY, Chang LF, Leng D, Lei J, Sui SF. Characterization of the structure and function of Escherichia coli DegQ as a representative of the DegQ-like proteases of bacterial HtrA family proteins. Structure 2011; 19:1328-37. [PMID: 21893291 DOI: 10.1016/j.str.2011.06.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Revised: 06/07/2011] [Accepted: 06/20/2011] [Indexed: 10/17/2022]
Abstract
HtrA family proteins play a central role in protein quality control in the bacterial periplasmic space. DegQ-like proteases, a group of bacterial HtrA proteins, are characterized by a short LA loop as compared with DegP-like proteases, and are found in many bacterial species. As a representative of the DegQ-like proteases, we report that Escherichia coli DegQ exists in vivo primarily as a trimer (substrate-free) or dodecamer (substrate-containing). Biochemical analysis of DegQ dodecamers revealed that the major copurified protein substrate is OmpA. Importantly, wild-type DegQ exhibited a much lower proteolytic activity, and thus higher chaperone-like activity, than DegP. Furthermore, using cryo-electron microscopy we determined high-resolution structures of DegQ 12- and 24-mers in the presence of substrate, thus revealing the structural mechanism by which DegQ moderates its proteolytic activity.
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Affiliation(s)
- Xiao-chen Bai
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University, Beijing 100084, China
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94
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Singh N, Kuppili RR, Bose K. The structural basis of mode of activation and functional diversity: a case study with HtrA family of serine proteases. Arch Biochem Biophys 2011; 516:85-96. [PMID: 22027029 DOI: 10.1016/j.abb.2011.10.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 10/03/2011] [Indexed: 12/15/2022]
Abstract
HtrA (High temperature requirement protease A) proteins that are primarily involved in protein quality control belong to a family of serine proteases conserved from bacteria to humans. HtrAs are oligomeric proteins that share a common trimeric pyramidal architecture where each monomer comprises a serine protease domain and one or two PDZ domains. Although the overall structural integrity is well maintained and they exhibit similar mechanism of activation, subtle conformational changes and structural plasticity especially in the flexible loop regions and domain interfaces lead to differences in their active site conformation and hence in their specificity and functions.
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Affiliation(s)
- Nitu Singh
- Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai, India
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95
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Interaction between bacterial outer membrane proteins and periplasmic quality control factors: a kinetic partitioning mechanism. Biochem J 2011; 438:505-11. [PMID: 21671888 DOI: 10.1042/bj20110264] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The OMPs (outer membrane proteins) of Gram-negative bacteria have to be translocated through the periplasmic space before reaching their final destination. The aqueous environment of the periplasmic space and high permeability of the outer membrane engender such a translocation process inevitably challenging. In Escherichia coli, although SurA, Skp and DegP have been identified to function in translocating OMPs across the periplasm, their precise roles and their relationship remain to be elucidated. In the present paper, by using fluorescence resonance energy transfer and single-molecule detection, we have studied the interaction between the OMP OmpC and these periplasmic quality control factors. The results of the present study reveal that the binding rate of OmpC to SurA or Skp is much faster than that to DegP, which may lead to sequential interaction between OMPs and different quality control factors. Such a kinetic partitioning mechanism for the chaperone-substrate interaction may be essential for the quality control of the biogenesis of OMPs.
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96
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Affiliation(s)
- Christine L. Hagan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Thomas J. Silhavy
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544;
| | - Daniel Kahne
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115; ,
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97
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Recombinant Deg/HtrA proteases from Synechocystis sp. PCC 6803 differ in substrate specificity, biochemical characteristics and mechanism. Biochem J 2011; 435:733-42. [PMID: 21332448 PMCID: PMC3195437 DOI: 10.1042/bj20102131] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Cyanobacteria require efficient protein-quality-control mechanisms to survive under dynamic, often stressful, environmental conditions. It was reported that three serine proteases, HtrA (high temperature requirement A), HhoA (HtrA homologue A) and HhoB (HtrA homologue B), are important for survival of Synechocystis sp. PCC 6803 under high light and temperature stresses and might have redundant physiological functions. In the present paper, we show that all three proteases can degrade unfolded model substrates, but differ with respect to cleavage sites, temperature and pH optima. For recombinant HhoA, and to a lesser extent for HtrA, we observed an interesting shift in the pH optimum from slightly acidic to alkaline in the presence of Mg2+ and Ca2+ ions. All three proteases formed different homo-oligomeric complexes with and without substrate, implying mechanistic differences in comparison with each other and with the well-studied Escherichia coli orthologues DegP (degradation of periplasmic proteins P) and DegS. Deletion of the PDZ domain decreased, but did not abolish, the proteolytic activity of all three proteases, and prevented substrate-induced formation of complexes higher than trimers by HtrA and HhoA. In summary, biochemical characterization of HtrA, HhoA and HhoB lays the foundation for a better understanding of their overlapping, but not completely redundant, stress-resistance functions in Synechocystis sp. PCC 6803.
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Sawa J, Malet H, Krojer T, Canellas F, Ehrmann M, Clausen T. Molecular adaptation of the DegQ protease to exert protein quality control in the bacterial cell envelope. J Biol Chem 2011; 286:30680-30690. [PMID: 21685389 DOI: 10.1074/jbc.m111.243832] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To react to distinct stress situations and to prevent the accumulation of misfolded proteins, all cells employ a number of proteases and chaperones, which together set up an efficient protein quality control system. The functionality of proteins in the cell envelope of Escherichia coli is monitored by the HtrA proteases DegS, DegP, and DegQ. In contrast with DegP and DegS, the structure and function of DegQ has not been addressed in detail. Here, we show that substrate binding triggers the conversion of the resting DegQ hexamer into catalytically active 12- and 24-mers. Interestingly, substrate-induced oligomer reassembly and protease activation depends on the first PDZ domain but not on the second. Therefore, the regulatory mechanism originally identified in DegP should be a common feature of HtrA proteases, most of which encompass only a single PDZ domain. Using a DegQ mutant lacking the second PDZ domain, we determined the high resolution crystal structure of a dodecameric HtrA complex. The nearly identical domain orientation of protease and PDZ domains within 12- and 24-meric HtrA complexes reveals a conserved PDZ1 → L3 → LD/L1/L2 signaling cascade, in which loop L3 senses the repositioned PDZ1 domain of higher order, substrate-engaged particles and activates protease function. Furthermore, our in vitro and in vivo data imply a pH-related function of DegQ in the bacterial cell envelope.
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Affiliation(s)
- Justyna Sawa
- Institute of Molecular Pathology, A-1030 Vienna, Austria
| | - Hélène Malet
- Department of Biological Sciences, Institute of Structural Molecular Biology, Birkbeck College, London WC1E 7HX, United Kingdom
| | - Tobias Krojer
- Institute of Molecular Pathology, A-1030 Vienna, Austria
| | | | - Michael Ehrmann
- Centre for Medical Biotechnology, Faculty of Biology and Geography, University Duisburg-Essen, 45117 Essen, Germany
| | - Tim Clausen
- Institute of Molecular Pathology, A-1030 Vienna, Austria.
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Abstract
Correct formation of disulfide bonds is critical for protein folding. We find that cells lacking protein disulfide isomerases (PDIs) can use alternative mechanisms for correct disulfide bond formation. By linking correct disulfide bond formation to antibiotic resistance, we selected mutants that catalyze correct disulfide formation in the absence of DsbC, Escherichia coli's PDI. Most of our mutants massively overproduce the disulfide oxidase DsbA and change its redox status. They enhance DsbA's ability to directly form the correct disulfides by increasing the level of mixed disulfides between DsbA and substrate proteins. One mutant operates via a different mechanism; it contains mutations in DsbB and CpxR that alter the redox environment of the periplasm and increases the level of the chaperone/protease DegP, allowing DsbA to gain disulfide isomerase ability in vivo. Thus, given the proper expression level, redox status, and chaperone assistance, the oxidase DsbA can readily function in vivo to catalyze the folding of proteins with complex disulfide bond connectivities. Our selection reveals versatile strategies for correct disulfide formation in vivo. Remarkably, our evolution of new pathways for correct disulfide bond formation in E. coli mimics eukaryotic PDI, a highly abundant partially reduced protein with chaperone activity.
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Affiliation(s)
- Guoping Ren
- Department of Molecular, Cellular, and Developmental Biology, Howard Hughes Medical Institute, University of Michigan, 830 N. University Ave., Ann Arbor, MI 48109-1048, USA
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The Legionella HtrA homologue DegQ is a self-compartmentizing protease that forms large 12-meric assemblies. Proc Natl Acad Sci U S A 2011; 108:10490-5. [PMID: 21670246 DOI: 10.1073/pnas.1101084108] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Proteases of the HtrA family are key factors dealing with folding stress in the periplasmatic compartment of prokaryotes. In Escherichia coli, the well-characterized HtrA family members DegS and DegP counteract the accumulation of unfolded outer-membrane proteins under stress conditions. Whereas DegS serves as a folding-stress sensor, DegP is a chaperone-protease facilitating refolding or degradation of defective outer-membrane proteins. Here, we report the 2.15-Å-resolution crystal structure of the second major chaperone-protease of the periplasm, DegQ from Legionella fallonii. DegQ assembles into large, cage-like 12-mers that form independently of unfolded substrate proteins. We provide evidence that 12-mer formation is essential for the degradation of substrate proteins but not for the chaperone activity of DegQ. In the current model for the regulation of periplasmatic chaperone-proteases, 6-meric assemblies represent important protease-resting states. However, DegQ is unable to form such 6-mers, suggesting divergent regulatory mechanisms for DegQ and DegP. To understand how the protease activity of DegQ is controlled, we probed its functional properties employing designed protein variants. Combining crystallographic, biochemical, and mutagenic data, we present a mechanistic model that suggests how protease activity of DegQ 12-mers is intrinsically regulated and how deleterious proteolysis by free DegQ 3-mers is prevented. Our study sheds light on a previously uncharacterized component of the prokaryotic stress-response system with implications for other members of the HtrA family.
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