1
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Blair JMA, Zeth K, Bavro VN, Sancho-Vaello E. The role of bacterial transport systems in the removal of host antimicrobial peptides in Gram-negative bacteria. FEMS Microbiol Rev 2022; 46:6617596. [PMID: 35749576 PMCID: PMC9629497 DOI: 10.1093/femsre/fuac032] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 05/23/2022] [Accepted: 06/22/2022] [Indexed: 01/09/2023] Open
Abstract
Antibiotic resistance is a global issue that threatens our progress in healthcare and life expectancy. In recent years, antimicrobial peptides (AMPs) have been considered as promising alternatives to the classic antibiotics. AMPs are potentially superior due to their lower rate of resistance development, since they primarily target the bacterial membrane ('Achilles' heel' of the bacteria). However, bacteria have developed mechanisms of AMP resistance, including the removal of AMPs to the extracellular space by efflux pumps such as the MtrCDE or AcrAB-TolC systems, and the internalization of AMPs to the cytoplasm by the Sap transporter, followed by proteolytic digestion. In this review, we focus on AMP transport as a resistance mechanism compiling all the experimental evidence for the involvement of efflux in AMP resistance in Gram-negative bacteria and combine this information with the analysis of the structures of the efflux systems involved. Finally, we expose some open questions with the aim of arousing the interest of the scientific community towards the AMPs-efflux pumps interactions. All the collected information broadens our understanding of AMP removal by efflux pumps and gives some clues to assist the rational design of AMP-derivatives as inhibitors of the efflux pumps.
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Affiliation(s)
- Jessica M A Blair
- College of Medical and Dental Sciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Kornelius Zeth
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000 Roskilde, Denmark
| | - Vassiliy N Bavro
- School of Life Sciences, University of Essex, Colchester, CO4 3SQ, United Kingdom
| | - Enea Sancho-Vaello
- Corresponding author. College of Medical and Dental Sciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom. E-mail:
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2
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Bukhari SZ, Zeth K, Iftikhar M, Rehman M, Usman Munir M, Khan WS, Ihsan A. Supramolecular lipid nanoparticles as delivery carriers for non-invasive cancer theranostics. Curr Res Pharmacol Drug Discov 2021; 2:100067. [PMID: 34909685 PMCID: PMC8663983 DOI: 10.1016/j.crphar.2021.100067] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/22/2021] [Accepted: 10/25/2021] [Indexed: 12/12/2022] Open
Abstract
Nanotheranostics is an emerging frontier of personalized medicine research particularly for cancer, which is the second leading cause of death. Supramolecular aspects in theranostics are quite allured to achieve more regulation and controlled features. Supramolecular nanotheranostics architecture is focused on engineering of modular supramolecular assemblies benefitting from their mutable and stimuli-responsive properties which confer an ultimate potential for the fabrication of unified innovative nanomedicines with controlled features. Amalgamation of supramolecular approaches to nano-based features further equip the potential of designing novel approaches to overcome limitations seen by the conventional theranostic strategies, for curing even the lethal diseases and endowing personalized therapeutics with optimistic prognosis, endorsing their clinical translation. Among many potential nanocarriers for theranostics, lipid nanoparticles (LNPs) have shown various promising advances in theranostics and their formulation can be tailored for several applications. Despite the great advancement in cancer nanotheranostics, there are still many challenges that need to be highlighted to fill the literature gap. For this purpose, herein, we have presented a systematic overview on the subject and proposed LNPs as the potential material to manage cancer via non-invasive approaches by highlighting the use of supramolecular approaches to make them robust for cancer theranostics. We have concluded the review by entailing the future perspectives of lipid nanotheranostics towards clinical translation.
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Affiliation(s)
- Syeda Zunaira Bukhari
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
| | - Kornelius Zeth
- Department of Science and Environment, Roskilde University Center, DK-4000 Roskilde, Denmark
| | - Maryam Iftikhar
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
| | - Mubashar Rehman
- Department of Pharmacy, Quaid-i-Azam University, Islamabad, Pakistan
| | - Muhammad Usman Munir
- Department of Pharmaceutical Chemistry, College of Pharmacy, Jouf University, Sakaka, Aljouf, 72388, Saudi Arabia
| | - Waheed S. Khan
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
| | - Ayesha Ihsan
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
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3
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Rasmussen HB, Jürgens G, Thomsen R, Taboureau O, Zeth K, Hansen PE, Hansen PR. Cellular Uptake and Intracellular Phosphorylation of GS-441524: Implications for Its Effectiveness against COVID-19. Viruses 2021; 13:v13071369. [PMID: 34372575 PMCID: PMC8310262 DOI: 10.3390/v13071369] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/27/2021] [Accepted: 07/07/2021] [Indexed: 12/22/2022] Open
Abstract
GS-441524 is an adenosine analog and the parent nucleoside of the prodrug remdesivir, which has received emergency approval for treatment of COVID-19. Recently, GS-441524 has been proposed to be effective in the treatment of COVID-19, perhaps even being superior to remdesivir for treatment of this disease. Evaluation of the clinical effectiveness of GS-441524 requires understanding of its uptake and intracellular conversion to GS-441524 triphosphate, the active antiviral substance. We here discuss the potential impact of these pharmacokinetic steps of GS-441524 on the formation of its active antiviral substance and effectiveness for treatment of COVID-19. Available protein expression data suggest that several adenosine transporters are expressed at only low levels in the epithelial cells lining the alveoli in the lungs, i.e., the alveolar cells or pneumocytes from healthy lungs. This may limit uptake of GS-441524. Importantly, cellular uptake of GS-441524 may be reduced during hypoxia and inflammation due to decreased expression of adenosine transporters. Similarly, hypoxia and inflammation may lead to reduced expression of adenosine kinase, which is believed to convert GS-441524 to GS-441524 monophosphate, the perceived rate-limiting step in the intracellular formation of GS-441524 triphosphate. Moreover, increases in extracellular and intracellular levels of adenosine, which may occur during critical illnesses, has the potential to competitively decrease cellular uptake and phosphorylation of GS-441524. Taken together, tissue hypoxia and severe inflammation in COVID-19 may lead to reduced uptake and phosphorylation of GS-441524 with lowered therapeutic effectiveness as a potential outcome. Hypoxia may be particularly critical to the ability of GS-441524 to eliminate SARS-CoV-2 from tissues with low basal expression of adenosine transporters, such as alveolar cells. This knowledge may also be relevant to treatments with other antiviral adenosine analogs and anticancer adenosine analogs as well.
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Affiliation(s)
- Henrik Berg Rasmussen
- Institute of Biological Psychiatry, Mental Health Centre Sct. Hans, DK-4000 Roskilde, Denmark
- Department of Science and Environment, Roskilde University Center, DK-4000 Roskilde, Denmark; (K.Z.); (P.E.H.)
- Correspondence:
| | - Gesche Jürgens
- Clinical Pharmacology Unit, Zealand University Hospital, DK-4000 Roskilde, Denmark;
| | - Ragnar Thomsen
- Section of Forensic Chemistry, Department of Forensic Medicine, Faculty of Health Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark;
| | - Olivier Taboureau
- INSERM U1133, CNRS UMR 8251, Université de Paris, F-75013 Paris, France;
| | - Kornelius Zeth
- Department of Science and Environment, Roskilde University Center, DK-4000 Roskilde, Denmark; (K.Z.); (P.E.H.)
| | - Poul Erik Hansen
- Department of Science and Environment, Roskilde University Center, DK-4000 Roskilde, Denmark; (K.Z.); (P.E.H.)
| | - Peter Riis Hansen
- Department of Cardiology, Herlev and Gentofte Hospital, DK-2900 Hellerup, Denmark;
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4
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Zeth K, Sancho-Vaello E. Structural Plasticity of LL-37 Indicates Elaborate Functional Adaptation Mechanisms to Bacterial Target Structures. Int J Mol Sci 2021; 22:ijms22105200. [PMID: 34068993 PMCID: PMC8156758 DOI: 10.3390/ijms22105200] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/28/2021] [Accepted: 05/12/2021] [Indexed: 11/16/2022] Open
Abstract
The human cathelicidin LL-37 is a multifunctional peptide of the human innate immune system. Among the various functions of LL-37, its antimicrobial activity is important in controlling the microorganisms of the human body. The target molecules of LL-37 in bacteria include membrane lipids, lipopolysaccharides (LPS), lipoteichoic acid (LTA), proteins, DNA and RNA. In this mini-review, we summarize the entity of LL-37 structural data determined over the last 15 years and specifically discuss features implicated in the interactions with lipid-like molecules. For this purpose, we discuss partial and full-length structures of LL-37 determined in the presence of membrane-mimicking detergents. This constantly growing structural database is now composed of monomers, dimers, tetramers, and fiber-like structures. The diversity of these structures underlines an unexpected plasticity and highlights the conformational and oligomeric adaptability of LL-37 necessary to target different molecular scaffolds. The recent co-crystal structures of LL-37 in complex with detergents are particularly useful to understand how these molecules mimic lipids and LPS to induce oligomerization and fibrillation. Defined detergent binding sites provide deep insights into a new class of peptide scaffolds, widening our view on the fascinating world of the LL-37 structural factotum. Together, the new structures in their evolutionary context allow for the assignment of functionally conserved residues in oligomerization and target interactions. Conserved phenylalanine and arginine residues primarily mediate those interactions with lipids and LPS. The interactions with macromolecules such as proteins or DNA remain largely unexplored and open a field for future studies aimed at structures of LL-37 complexes. These complexes will then allow for the structure-based rational design of LL-37-derived peptides with improved antibiotic properties.
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Affiliation(s)
- Kornelius Zeth
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000 Roskilde, Denmark
- Correspondence: (K.Z.); (E.S.-V.); Tel.: +45-604-666-29 (K.Z.)
| | - Enea Sancho-Vaello
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
- Correspondence: (K.Z.); (E.S.-V.); Tel.: +45-604-666-29 (K.Z.)
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5
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Sancho-Vaello E, Gil-Carton D, François P, Bonetti EJ, Kreir M, Pothula KR, Kleinekathöfer U, Zeth K. The structure of the antimicrobial human cathelicidin LL-37 shows oligomerization and channel formation in the presence of membrane mimics. Sci Rep 2020; 10:17356. [PMID: 33060695 PMCID: PMC7562864 DOI: 10.1038/s41598-020-74401-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 09/26/2020] [Indexed: 12/22/2022] Open
Abstract
The human cathelicidin LL-37 serves a critical role in the innate immune system defending bacterial infections. LL-37 can interact with molecules of the cell wall and perforate cytoplasmic membranes resulting in bacterial cell death. To test the interactions of LL-37 and bacterial cell wall components we crystallized LL-37 in the presence of detergents and obtained the structure of a narrow tetrameric channel with a strongly charged core. The formation of a tetramer was further studied by cross-linking in the presence of detergents and lipids. Using planar lipid membranes a small but defined conductivity of this channel could be demonstrated. Molecular dynamic simulations underline the stability of this channel in membranes and demonstrate pathways for the passage of water molecules. Time lapse studies of E. coli cells treated with LL-37 show membrane discontinuities in the outer membrane followed by cell wall damage and cell death. Collectively, our results open a venue to the understanding of a novel AMP killing mechanism and allows the rational design of LL-37 derivatives with enhanced bactericidal activity.
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Affiliation(s)
- Enea Sancho-Vaello
- Unidad de Biofisica, Centro Mixto Consejo Superior de Investigaciones Cientificas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia, Spain.,Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - David Gil-Carton
- Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia Edificio 800, 48160, Derio, Spain
| | - Patrice François
- Genomic Research Laboratory, Department of Medical Specialities, Geneva University Hospitals, University of Geneva, Genève, Switzerland
| | - Eve-Julie Bonetti
- Genomic Research Laboratory, Department of Medical Specialities, Geneva University Hospitals, University of Geneva, Genève, Switzerland
| | - Mohamed Kreir
- Nanion Technologies GmbH, Gabrielenstraße 9, 80636, Munich, Germany.,Janssen Pharmaceutica NV, Janssen R&D, Nonclinical Safety, Beerse, Belgium
| | - Karunakar Reddy Pothula
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany
| | - Kornelius Zeth
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000, Roskilde, Denmark.
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6
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Micevski D, Zeth K, Mulhern TD, Schuenemann VJ, Zammit JE, Truscott KN, Dougan DA. Insight into the RssB-Mediated Recognition and Delivery of σ s to the AAA+ Protease, ClpXP. Biomolecules 2020; 10:E615. [PMID: 32316259 PMCID: PMC7226468 DOI: 10.3390/biom10040615] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/18/2020] [Accepted: 04/11/2020] [Indexed: 11/23/2022] Open
Abstract
In Escherichia coli, SigmaS (σS) is the master regulator of the general stress response. The cellular levels of σS are controlled by transcription, translation and protein stability. The turnover of σS, by the AAA+ protease (ClpXP), is tightly regulated by a dedicated adaptor protein, termed RssB (Regulator of Sigma S protein B)-which is an atypical member of the response regulator (RR) family. Currently however, the molecular mechanism of σS recognition and delivery by RssB is only poorly understood. Here we describe the crystal structures of both RssB domains (RssBN and RssBC) and the SAXS analysis of full-length RssB (both free and in complex with σS). Together with our biochemical analysis we propose a model for the recognition and delivery of σS by this essential adaptor protein. Similar to most bacterial RRs, the N-terminal domain of RssB (RssBN) comprises a typical mixed (βα)5-fold. Although phosphorylation of RssBN (at Asp58) is essential for high affinity binding of σS, much of the direct binding to σS occurs via the C-terminal effector domain of RssB (RssBC). In contrast to most RRs the effector domain of RssB forms a β-sandwich fold composed of two sheets surrounded by α-helical protrusions and as such, shares structural homology with serine/threonine phosphatases that exhibit a PPM/PP2C fold. Our biochemical data demonstrate that this domain plays a key role in both substrate interaction and docking to the zinc binding domain (ZBD) of ClpX. We propose that RssB docking to the ZBD of ClpX overlaps with the docking site of another regulator of RssB, the anti-adaptor IraD. Hence, we speculate that docking to ClpX may trigger release of its substrate through activation of a "closed" state (as seen in the RssB-IraD complex), thereby coupling adaptor docking (to ClpX) with substrate release. This competitive docking to RssB would prevent futile interaction of ClpX with the IraD-RssB complex (which lacks a substrate). Finally, substrate recognition by RssB appears to be regulated by a key residue (Arg117) within the α5 helix of the N-terminal domain. Importantly, this residue is not directly involved in σS interaction, as σS binding to the R117A mutant can be restored by phosphorylation. Likewise, R117A retains the ability to interact with and activate ClpX for degradation of σS, both in the presence and absence of acetyl phosphate. Therefore, we propose that this region of RssB (the α5 helix) plays a critical role in driving interaction with σS at a distal site.
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Affiliation(s)
- Dimce Micevski
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia; (D.M.); (J.E.Z.)
| | - Kornelius Zeth
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, D-72076 Tübingen, Germany; (K.Z.); (V.J.S.)
- Department of Science and Environment, Roskilde University, DK-4000 Roskilde, Denmark
| | - Terrence D. Mulhern
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville 3010, Victoria, Australia;
| | - Verena J. Schuenemann
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, D-72076 Tübingen, Germany; (K.Z.); (V.J.S.)
| | - Jessica E. Zammit
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia; (D.M.); (J.E.Z.)
| | - Kaye N. Truscott
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia; (D.M.); (J.E.Z.)
| | - David A. Dougan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia; (D.M.); (J.E.Z.)
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7
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Abstract
Iron storage in biology is carried out by cage-shaped proteins of the ferritin superfamily, one of which is the dodecameric protein Dps. In Dps, four distinct steps lead to the formation of metal nanoparticles: attraction of ion-aquo complexes to the protein matrix, passage of these complexes through translocation pores, oxidation of these complexes at ferroxidase centers, and, ultimately, nanoparticle formation. In this study, we investigated Dps from Listeria innocua to structurally characterize these steps for Co2+, Zn2+, and La3+ ions. The structures reveal that differences in their ion coordination chemistry determine alternative metal ion-binding sites on the areas of the surface surrounding the translocation pore that captures nine La3+, three Co2+, or three Zn2+ ions as aquo clusters and passes them on for translocation. Inside these pores, ion-selective conformational changes at key residues occur before a gating residue to actively move ions through the constriction zone. Ions upstream of the Asp130 gate residue are typically hydrated, while ions downstream directly interact with the protein matrix. Inside the cavity, ions move along negatively charged residues to the ferroxidase center, where seven main residues adapt to the three different ions by dynamically changing their conformations. In total, we observed more than 20 metal-binding sites per Dps monomer, which clearly highlights the metal-binding capacity of this protein family. Collectively, our results provide a detailed structural description of the preparative steps for amino acid-assisted biomineralization in Dps proteins, demonstrating unexpected protein matrix plasticity.
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Affiliation(s)
- Kornelius Zeth
- Roskilde University , Department of Science and Environment , Universitetsvej 1 , 4000 Roskilde , Denmark.,Universidad del Pais Vasco (UPV/EHU) , 48940 Leioa , Basque Country , Spain
| | - Enea Sancho-Vaello
- Unidad de Biofisica, Consejo Superior de Investigaciones Científicas , Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU) , Barrio Sarriena s/n, Leioa , 48940 Leioa , Basque Country , Spain
| | - Mitsuhiro Okuda
- Unidad de Biofisica, Consejo Superior de Investigaciones Científicas , Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU) , Barrio Sarriena s/n, Leioa , 48940 Leioa , Basque Country , Spain.,CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain.,IKERBASQUE , Basque Foundation for Science , 48011 Bilbao , Basque Country , Spain
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8
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Plotka M, Sancho-Vaello E, Dorawa S, Kaczorowska AK, Kozlowski LP, Kaczorowski T, Zeth K. Structure and function of the Ts2631 endolysin of Thermus scotoductus phage vB_Tsc2631 with unique N-terminal extension used for peptidoglycan binding. Sci Rep 2019; 9:1261. [PMID: 30718611 PMCID: PMC6361986 DOI: 10.1038/s41598-018-37417-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/30/2018] [Indexed: 02/07/2023] Open
Abstract
To escape from hosts after completing their life cycle, bacteriophages often use endolysins, which degrade bacterial peptidoglycan. While mesophilic phages have been extensively studied, their thermophilic counterparts are not well characterized. Here, we present a detailed analysis of the structure and function of Ts2631 endolysin from thermophilic phage vB_Tsc2631, which is a zinc-dependent amidase. The active site of Ts2631 consists of His30, Tyr58, His131 and Cys139, which are involved in Zn2+ coordination and catalysis. We found that the active site residues are necessary for lysis yet not crucial for peptidoglycan binding. To elucidate residues involved in the enzyme interaction with peptidoglycan, we tested single-residue substitution variants and identified Tyr60 and Lys70 as essential residues. Moreover, substitution of Cys80, abrogating disulfide bridge formation, inactivates Ts2631, as do substitutions of His31, Thr32 and Asn85 residues. The endolysin contains a positively charged N-terminal extension of 20 residues that can protrude from the remainder of the enzyme and is crucial for peptidoglycan binding. We show that the deletion of 20 residues from the N-terminus abolished the bacteriolytic activity of the enzyme. Because Ts2631 exhibits intrinsic antibacterial activity and unusual thermal stability, it is perfectly suited as a scaffold for the development of antimicrobial agents.
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Affiliation(s)
- Magdalena Plotka
- Laboratory of Extremophiles Biology, Department of Microbiology, Faculty of Biology, University of Gdansk, Gdansk, Poland.
| | - Enea Sancho-Vaello
- Unidad de Biofisica, Centro Mixto Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC,UPV/EHU), Leioa, Bizkaia, Spain
| | - Sebastian Dorawa
- Laboratory of Extremophiles Biology, Department of Microbiology, Faculty of Biology, University of Gdansk, Gdansk, Poland
| | - Anna-Karina Kaczorowska
- Collection of Plasmids and Microorganisms, Faculty of Biology, University of Gdansk, Gdansk, Poland
| | - Lukasz P Kozlowski
- Institute of Informatics, Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Warsaw, Poland
| | - Tadeusz Kaczorowski
- Laboratory of Extremophiles Biology, Department of Microbiology, Faculty of Biology, University of Gdansk, Gdansk, Poland.
| | - Kornelius Zeth
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
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9
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Zeth K, Zachariae U. Ten Years of High Resolution Structural Research on the Voltage Dependent Anion Channel (VDAC)-Recent Developments and Future Directions. Front Physiol 2018; 9:108. [PMID: 29563878 PMCID: PMC5845903 DOI: 10.3389/fphys.2018.00108] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 02/02/2018] [Indexed: 12/20/2022] Open
Abstract
Mitochondria are evolutionarily related to Gram-negative bacteria and both comprise two membrane systems with strongly differing protein composition. The major protein in the outer membrane of mitochondria is the voltage-dependent anion channel (VDAC), which mediates signal transmission across the outer membrane but also the exchange of metabolites, most importantly ADP and ATP. More than 30 years after its discovery three identical high-resolution structures were determined in 2008. These structures show a 19-stranded anti-parallel beta-barrel with an N-terminal helix located inside. An odd number of beta-strands is also shared by Tom40, another member of the VDAC superfamily. This indicates that this superfamily is evolutionarily relatively young and that it has emerged in the context of mitochondrial evolution. New structural information obtained during the last decade on Tom40 can be used to cross-validate the structure of VDAC and vice versa. Interpretation of biochemical and biophysical studies on both protein channels now rests on a solid basis of structural data. Over the past 10 years, complementary structural and functional information on proteins of the VDAC superfamily has been collected from in-organello, in-vitro, and in silico studies. Most of these findings have confirmed the validity of the original structures. This short article briefly reviews the most important advances on the structure and function of VDAC superfamily members collected during the last decade and summarizes how they enhanced our understanding of the channel.
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Affiliation(s)
- Kornelius Zeth
- Department for Science and Environment, Roskilde University, Roskilde, Denmark
| | - Ulrich Zachariae
- School of Science and Engineering, University of Dundee, Dundee, United Kingdom.,School of Life Sciences, University of Dundee, Dundee, United Kingdom
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10
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Zeth K, Sancho-Vaello E. The Human Antimicrobial Peptides Dermcidin and LL-37 Show Novel Distinct Pathways in Membrane Interactions. Front Chem 2017; 5:86. [PMID: 29164103 PMCID: PMC5681987 DOI: 10.3389/fchem.2017.00086] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 10/11/2017] [Indexed: 01/11/2023] Open
Abstract
Mammals protect themselves from inflammation triggered by microorganisms through secretion of antimicrobial peptides (AMPs). One mechanism by which AMPs kill bacterial cells is perforating their membranes. Membrane interactions and pore formation were investigated for α-helical AMPs leading to the formulation of three basic mechanistic models: the barrel stave, toroidal, and carpet model. One major drawback of these models is their simplicity. They do not reflect the real in vitro and in vivo conditions. To challenge and refine these models using a structure-based approach we set out to investigate how human cathelicidin (LL-37) and dermcidin (DCD) interact with membranes. Both peptides are α-helical and their structures have been solved at atomic resolution. DCD assembles in solution into a hexameric pre-channel complex before the actual membrane targeting and integration step can occur, and the complex follows a deviation of the barrel stave model. LL-37 interacts with lipids and shows the formation of oligomers generating fibril-like supramolecular structures on membranes. LL-37 further assembles into transmembrane pores with yet unknown structure expressing a deviation of the toroidal pore model. Both of their specific targeting mechanisms will be discussed in the context of the “old” models propagated in the literature.
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Affiliation(s)
- Kornelius Zeth
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | - Enea Sancho-Vaello
- Laboratory of Biochemistry, Institut Químic de Sarrià, Universitat Ramon Llull, Barcelona, Spain
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11
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Zeth K, Hoiczyk E, Okuda M. Ferroxidase-Mediated Iron Oxide Biomineralization: Novel Pathways to Multifunctional Nanoparticles. Trends Biochem Sci 2016; 41:190-203. [DOI: 10.1016/j.tibs.2015.11.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 11/20/2015] [Accepted: 11/24/2015] [Indexed: 11/29/2022]
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12
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Affiliation(s)
- Enea Sancho-Vaello
- Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia, Spain
| | - Kornelius Zeth
- Department of Biochemistry & Molecular Biology, University of the Basque Country, Barrio Sarriena s/n, Leioa, Bizkaia, Spain.,NanoGUNE, San Sebastian, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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13
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Hicks KG, Delbecq SP, Sancho-Vaello E, Blanc MP, Dove KK, Prost LR, Daley ME, Zeth K, Klevit RE, Miller SI. Acidic pH and divalent cation sensing by PhoQ are dispensable for systemic salmonellae virulence. eLife 2015; 4:e06792. [PMID: 26002083 PMCID: PMC4473727 DOI: 10.7554/elife.06792] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 05/22/2015] [Indexed: 12/30/2022] Open
Abstract
Salmonella PhoQ is a histidine kinase with a periplasmic sensor domain (PD) that promotes virulence by detecting the macrophage phagosome. PhoQ activity is repressed by divalent cations and induced in environments of acidic pH, limited divalent cations, and cationic antimicrobial peptides (CAMP). Previously, it was unclear which signals are sensed by salmonellae to promote PhoQ-mediated virulence. We defined conformational changes produced in the PhoQ PD on exposure to acidic pH that indicate structural flexibility is induced in α-helices 4 and 5, suggesting this region contributes to pH sensing. Therefore, we engineered a disulfide bond between W104C and A128C in the PhoQ PD that restrains conformational flexibility in α-helices 4 and 5. PhoQW104C-A128C is responsive to CAMP, but is inhibited for activation by acidic pH and divalent cation limitation. phoQW104C-A128CSalmonella enterica Typhimurium is virulent in mice, indicating that acidic pH and divalent cation sensing by PhoQ are dispensable for virulence. DOI:http://dx.doi.org/10.7554/eLife.06792.001 Salmonella bacteria cause illnesses in humans, such as food poisoning and typhoid fever. In response to a Salmonella infection, immune cells known as macrophages detect and engulf the bacteria. The conditions inside the macrophage (which include an acidic pH and high levels of antimicrobial molecules) can destroy some bacteria. However, Salmonella bacteria (which are also called salmonellae) can sense and counteract these hostile conditions; this allows them to remodel their surface to survive and reproduce inside macrophages and continue to cause disease. A protein known as PhoQ, which is found on the surface of Salmonella bacteria, is a sensor that detects when the bacterium is inside a macrophage and so needs to boost its defenses. The PhoQ sensor is able to respond to acidity, the absence of divalent cations—such as magnesium and calcium ions—and certain antimicrobial peptide molecules. These conditions and components are used inside macrophages to try and kill the bacteria, but it was not known which of these signals PhoQ actually senses during an infection. Hicks et al. established how the sensor region of PhoQ changes when it is exposed to acid. This knowledge enabled variants of this protein to be constructed that do not respond when exposed to acidic conditions or low levels of divalent cations. Salmonellae that have these modified PhoQ sensors were still able to infect macrophages and cause disease in mice. These findings suggest that antimicrobial peptide sensing alone is sufficient to trigger the bacteria's defenses inside host organisms. Understanding how salmonellae detect antimicrobial factors could help with the development of new treatments for the diseases caused by these bacteria. Furthermore, the new tools developed by Hicks et al. could be applied to other systems to characterize how bacteria interact with their host environment during infection. DOI:http://dx.doi.org/10.7554/eLife.06792.002
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Affiliation(s)
- Kevin G Hicks
- Department of Microbiology, University of Washington Medical School, Seattle, United States
| | - Scott P Delbecq
- Department of Biochemistry, University of Washington Medical School, Seattle, United States
| | - Enea Sancho-Vaello
- Unidad de Biofisica, Centro Mixto Consejo Superior de Investigaciones Cientificas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC,UPV/EHU), Leioa, Bizkaia, Spain
| | - Marie-Pierre Blanc
- Department of Microbiology, University of Washington Medical School, Seattle, United States
| | - Katja K Dove
- Department of Biochemistry, University of Washington Medical School, Seattle, United States
| | - Lynne R Prost
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Margaret E Daley
- Department of Chemistry and Biochemistry, University of San Diego, San Diego, United States
| | - Kornelius Zeth
- Department of Biochemistry and Molecular Biology, University of Basque Country, Leioa, Spain
| | - Rachel E Klevit
- Department of Biochemistry, University of Washington Medical School, Seattle, United States
| | - Samuel I Miller
- Department of Microbiology, University of Washington Medical School, Seattle, United States
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14
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Morgado L, Zeth K, Burmann BM, Maier T, Hiller S. Characterization of the insertase BamA in three different membrane mimetics by solution NMR spectroscopy. J Biomol NMR 2015; 61:333-45. [PMID: 25638436 DOI: 10.1007/s10858-015-9906-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/22/2015] [Indexed: 05/22/2023]
Abstract
The insertase BamA is the central protein of the Bam complex responsible for outer membrane protein biogenesis in Gram-negative bacteria. BamA features a 16-stranded transmembrane β-barrel and five periplasmic POTRA domains, with a total molecular weight of 88 kDa. Whereas the structure of BamA has recently been determined by X-ray crystallography, its functional mechanism is not well understood. This mechanism comprises the insertion of substrates from a dynamic, chaperone-bound state into the bacterial outer membrane, and NMR spectroscopy is thus a method of choice for its elucidation. Here, we report solution NMR studies of different BamA constructs in three different membrane mimetic systems: LDAO micelles, DMPC:DiC7PC bicelles and MSP1D1:DMPC nanodiscs. The impact of biochemical parameters on the spectral quality was investigated, including the total protein concentration and the detergent:protein ratio. The barrel of BamA is folded in micelles, bicelles and nanodiscs, but the N-terminal POTRA5 domain is flexibly unfolded in the absence of POTRA4. Measurements of backbone dynamics show that the variable insertion region of BamA, located in the extracellular lid loop L6, features high local flexibility. Our work establishes biochemical preparation schemes for BamA, which will serve as a platform for structural and functional studies of BamA and its role within the Bam complex by solution NMR spectroscopy.
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Abstract
Outer membrane protein biogenesis is a fundamental and essential process in all Gram-negative bacteria. The key players conducting this process are organized in the β-barrel assembly machinery (BAM) complex. This complex has recently attracted a lot of attention due to its importance in cell wall generation, maintenance, and the fascinating yet partially unknown mechanism. The currently best studied example is the BAM complex from E. coli which comprises five proteins, BamA-BamE, two of which, BamA and BamD, are essential for cell survival. Four of the complex proteins, BamB-BamE, are lipoproteins and are attached to the outer membrane via N-terminal lipid anchors. Two of them, BamB and BamD, comprise protein folds known to mediate protein-protein interactions through WD40 and TPR domains, respectively. Structures of BamB to BamE have been determined using X-ray crystallography, NMR and SAXS techniques. Details on protein preparation, crystallization, data acquisition, and determination of structures are given here along with the brief summary of the currently available structural Bam protein repertoire.
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Affiliation(s)
- Kornelius Zeth
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland.
- Ikerbasque, Basque Foundation of Science, Maria Diaz de Haro 3, Floor 6, Bilbao, 48013, Spain.
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16
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Sammito M, Millán C, Rodríguez DD, de Ilarduya IM, Meindl K, De Marino I, Petrillo G, Buey RM, de Pereda JM, Zeth K, Sheldrick GM, Usón I. Erratum: Corrigendum: Exploiting tertiary structure through local folds for crystallographic phasing. Nat Methods 2014. [DOI: 10.1038/nmeth0714-773b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Grinter R, Josts I, Zeth K, Roszak AW, McCaughey LC, Cogdell RJ, Milner JJ, Kelly SM, Byron O, Walker D. Structure of the atypical bacteriocin pectocin M2 implies a novel mechanism of protein uptake. Mol Microbiol 2014; 93:234-46. [PMID: 24865810 PMCID: PMC4671253 DOI: 10.1111/mmi.12655] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2014] [Indexed: 01/08/2023]
Abstract
The colicin-like bacteriocins are potent protein antibiotics that have evolved to efficiently cross the outer membrane of Gram-negative bacteria by parasitizing nutrient uptake systems. We have structurally characterized the colicin M-like bacteriocin, pectocin M2, which is active against strains of Pectobacterium spp. This unusual bacteriocin lacks the intrinsically unstructured translocation domain that usually mediates translocation of these bacteriocins across the outer membrane, containing only a single globular ferredoxin domain connected to its cytotoxic domain by a flexible α-helix, which allows it to adopt two distinct conformations in solution. The ferredoxin domain of pectocin M2 is homologous to plant ferredoxins and allows pectocin M2 to parasitize a system utilized by Pectobacterium to obtain iron during infection of plants. Furthermore, we identify a novel ferredoxin-containing bacteriocin pectocin P, which possesses a cytotoxic domain homologous to lysozyme, illustrating that the ferredoxin domain acts as a generic delivery module for cytotoxic domains in Pectobacterium.
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Affiliation(s)
- Rhys Grinter
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8QQ, UK
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18
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Albrecht R, Schütz M, Oberhettinger P, Faulstich M, Bermejo I, Rudel T, Diederichs K, Zeth K. Structure of BamA, an essential factor in outer membrane protein biogenesis. ACTA ACUST UNITED AC 2014; 70:1779-89. [PMID: 24914988 DOI: 10.1107/s1399004714007482] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 04/03/2014] [Indexed: 11/10/2022]
Abstract
Outer membrane protein (OMP) biogenesis is an essential process for maintaining the bacterial cell envelope and involves the β-barrel assembly machinery (BAM) for OMP recognition, folding and assembly. In Escherichia coli this function is orchestrated by five proteins: the integral outer membrane protein BamA of the Omp85 superfamily and four associated lipoproteins. To unravel the mechanism underlying OMP folding and insertion, the structure of the E. coli BamA β-barrel and P5 domain was determined at 3 Å resolution. These data add information beyond that provided in the recently published crystal structures of BamA from Haemophilus ducreyi and Neisseria gonorrhoeae and are a valuable basis for the interpretation of pertinent functional studies. In an `open' conformation, E. coli BamA displays a significant degree of flexibility between P5 and the barrel domain, which is indicative of a multi-state function in substrate transfer. E. coli BamA is characterized by a discontinuous β-barrel with impaired β1-β16 strand interactions denoted by only two connecting hydrogen bonds and a disordered C-terminus. The 16-stranded barrel surrounds a large cavity which implies a function in OMP substrate binding and partial folding. These findings strongly support a mechanism of OMP biogenesis in which substrates are partially folded inside the barrel cavity and are subsequently released laterally into the lipid bilayer.
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Affiliation(s)
- Reinhard Albrecht
- Department of Protein Evolution, Max-Planck-Institut für Entwicklungsbiologie, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Monika Schütz
- Institut für Medizinische Mikrobiologie und Hygiene, Elfriede-Aulhorn-Strasse 6, 72076 Tübingen, Germany
| | - Philipp Oberhettinger
- Institut für Medizinische Mikrobiologie und Hygiene, Elfriede-Aulhorn-Strasse 6, 72076 Tübingen, Germany
| | - Michaela Faulstich
- Department for Microbiology, Biocenter of the University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Ivan Bermejo
- Unidad de Biofisica (CSIC-UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Vizcaya, Spain
| | - Thomas Rudel
- Department for Microbiology, Biocenter of the University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Kay Diederichs
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Kornelius Zeth
- Department of Protein Evolution, Max-Planck-Institut für Entwicklungsbiologie, Spemannstrasse 35, 72076 Tübingen, Germany
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19
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Ferris HU, Zeth K, Hulko M, Dunin-Horkawicz S, Lupas AN. Axial helix rotation as a mechanism for signal regulation inferred from the crystallographic analysis of the E. coli serine chemoreceptor. J Struct Biol 2014; 186:349-56. [PMID: 24680785 DOI: 10.1016/j.jsb.2014.03.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 03/14/2014] [Accepted: 03/17/2014] [Indexed: 11/19/2022]
Abstract
Bacterial chemotaxis receptors are elongated homodimeric coiled-coil bundles, which transduce signals generated in an N-terminal sensor domain across 15-20nm to a conserved C-terminal signaling subdomain. This signal transduction regulates the activity of associated kinases, altering the behavior of the flagellar motor and hence cell motility. Signaling is in turn modulated by selective methylation and demethylation of specific glutamate and glutamine residues in an adaptation subdomain. We have determined the structure of a chimeric protein, consisting of the HAMP domain from Archaeoglobus fulgidus Af1503 and the methyl-accepting domain of Escherichia coli Tsr. It shows a 21nm coiled coil that alternates between two coiled-coil packing modes: canonical knobs-into-holes and complementary x-da, a variant form related to the canonical one by axial rotation of the helices. Comparison of the obtained structure to the Thermotoga maritima chemoreceptor TM1143 reveals that they adopt different axial rotation states in their adaptation subdomains. This conformational change is presumably induced by the upstream HAMP domain and may modulate the affinity of the chemoreceptor to the methylation-demethylation system. The presented findings extend the cogwheel model for signal transmission to chemoreceptors.
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Affiliation(s)
- Hedda U Ferris
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Kornelius Zeth
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Michael Hulko
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Stanislaw Dunin-Horkawicz
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Andrei N Lupas
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
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Zeth K, Fokina O, Forchhammer K. Structural basis and target-specific modulation of ADP sensing by the Synechococcus elongatus PII signaling protein. J Biol Chem 2014; 289:8960-72. [PMID: 24519945 DOI: 10.1074/jbc.m113.536557] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PII signaling proteins comprise one of the most versatile signaling devices in nature and have a highly conserved structure. In cyanobacteria, PipX and N-acetyl-L-glutamate kinase are receptors of PII signaling, and these interactions are modulated by ADP, ATP, and 2-oxoglutarate. These effector molecules bind interdependently to three anti-cooperative binding sites on the trimeric PII protein and thereby affect its structure. Here we used the PII protein from Synechococcus elongatus PCC 7942 to reveal the structural basis of anti-cooperative ADP binding. Furthermore, we clarified the mutual influence of PII-receptor interaction and sensing of the ATP/ADP ratio. The crystal structures of two forms of trimeric PII, one with one ADP bound and the other with all three ADP-binding sites occupied, revealed significant differences in the ADP binding mode: at one site (S1) ADP is tightly bound through side-chain and main-chain interactions, whereas at the other two sites (S2 and S3) the ADP molecules are only bound by main-chain interactions. In the presence of the PII-receptor PipX, the affinity of ADP to the first binding site S1 strongly increases, whereas the affinity for ATP decreases due to PipX favoring the S1 conformation of PII-ADP. In consequence, the PII-PipX interaction is highly sensitive to subtle fluctuations in the ATP/ADP ratio. By contrast, the PII-N-acetyl-L-glutamate kinase interaction, which is negatively affected by ADP, is insensitive to these fluctuations. Modulation of the metabolite-sensing properties of PII by its receptors allows PII to differentially perceive signals in a target-specific manner and to perform multitasking signal transduction.
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Affiliation(s)
- Kornelius Zeth
- From the Max Planck Institute for Developmental Biology, Department of Protein Evolution, Spemannstrasse 35, 72076 Tübingen, Germany and
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21
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Kryshtafovych A, Moult J, Bales P, Bazan JF, Biasini M, Burgin A, Chen C, Cochran FV, Craig TK, Das R, Fass D, Garcia-Doval C, Herzberg O, Lorimer D, Luecke H, Ma X, Nelson DC, van Raaij MJ, Rohwer F, Segall A, Seguritan V, Zeth K, Schwede T. Challenging the state of the art in protein structure prediction: Highlights of experimental target structures for the 10th Critical Assessment of Techniques for Protein Structure Prediction Experiment CASP10. Proteins 2014; 82 Suppl 2:26-42. [PMID: 24318984 PMCID: PMC4072496 DOI: 10.1002/prot.24489] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Revised: 11/01/2013] [Accepted: 11/09/2013] [Indexed: 11/12/2022]
Abstract
For the last two decades, CASP has assessed the state of the art in techniques for protein structure prediction and identified areas which required further development. CASP would not have been possible without the prediction targets provided by the experimental structural biology community. In the latest experiment, CASP10, more than 100 structures were suggested as prediction targets, some of which appeared to be extraordinarily difficult for modeling. In this article, authors of some of the most challenging targets discuss which specific scientific question motivated the experimental structure determination of the target protein, which structural features were especially interesting from a structural or functional perspective, and to what extent these features were correctly reproduced in the predictions submitted to CASP10. Specifically, the following targets will be presented: the acid-gated urea channel, a difficult to predict transmembrane protein from the important human pathogen Helicobacter pylori; the structure of human interleukin (IL)-34, a recently discovered helical cytokine; the structure of a functionally uncharacterized enzyme OrfY from Thermoproteus tenax formed by a gene duplication and a novel fold; an ORFan domain of mimivirus sulfhydryl oxidase R596; the fiber protein gene product 17 from bacteriophage T7; the bacteriophage CBA-120 tailspike protein; a virus coat protein from metagenomic samples of the marine environment; and finally, an unprecedented class of structure prediction targets based on engineered disulfide-rich small proteins.
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Affiliation(s)
- Andriy Kryshtafovych
- Genome Center, University of California, Davis, 451 Health Sciences Drive, Davis, California 95616,
| | - John Moult
- Institute for Bioscience and Biotechnology Research, Department of Cell Biology and Molecular genetics, University of Maryland, 9600 Gudelsky Drive, Rockville, MD 20850, USA;
| | - Patrick Bales
- Institute for Bioscience and Biotechnology Research, University of Maryland, 9600 Gudelsky Drive, Rockville, MD 20850, USA;
| | - J. Fernando Bazan
- (1) Departments of Protein Engineering and (2) Structural Biology, Genentech, 1 DNA Way, South San Francisco, CA 94080, (3) Present address: 44th & Aspen Life Sciences, 924 4th St. N., Stillwater, MN 55082,
| | - Marco Biasini
- (1) Biozentrum, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland; (2) SIB Swiss Institute of Bioinformatics, Klingelbergstrasse 50, 4056 Basel, Switzerland;
| | - Alex Burgin
- Broad Institute, 5 Cambridge Center, Cambridge, MA 02142, USA;
| | - Chen Chen
- Institute for Bioscience and Biotechnology Research, University of Maryland, 9600 Gudelsky Drive, Rockville, MD 20850, USA;
| | - Frank V. Cochran
- Department of Biochemistry, Stanford University, Stanford, California, 94305, USA;
| | | | - Rhiju Das
- (1) Department of Biochemistry, Stanford University, Stanford, California, 94305, USA; (2) Department of Physics, Stanford University, Stanford, California, 94305, USA,
| | - Deborah Fass
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100 Israel, Tel: +972-8-934-3214; Fax: +972-8-934-4136;
| | - Carmela Garcia-Doval
- Centro Nactional de Biotecnologia (CNB-CSIC), calle Darwin 3, E-28049 Madrid, Spain.
| | - Osnat Herzberg
- (1) Institute for Bioscience and Biotechnology Research, University of Maryland, 9600 Gudelsky Drive, Rockville, MD 20850, USA; (2) Department of Chemistry and Biochemistry, University of Maryland, College Park;
| | - Donald Lorimer
- Emerald Bio, 7869 NE Day Rd W, Bainbridge Isle, WA 98110, USA;
| | - Hartmut Luecke
- Center for Biomembrane Systems and Depts. of Biochemistry, Biophysics & Computer Science, 3205 McGaugh Hall, University of California, Irvine, CA 92697-3900, USA;
| | - Xiaolei Ma
- (1) Departments of Protein Engineering and (2) Structural Biology, Genentech, 1 DNA Way, South San Francisco, CA 94080 (3) Present address: Novartis Institutes for Biomedical Research, 4560 Horton St., Emeryville, CA 94608, USA;
| | - Daniel C. Nelson
- (1) Institute for Bioscience and Biotechnology Research, University of Maryland, 9600 Gudelsky Drive, Rockville, MD 20850, USA; (2) Department of Veterinary Medicine, University of Maryland, College Park,
| | - Mark J. van Raaij
- Centro Nactional de Biotecnologia (CNB-CSIC), calle Darwin 3, E-28049 Madrid, Spain.
| | - Forest Rohwer
- Department of Biology, San Diego State University, San Diego, CA 92182, USA;
| | - Anca Segall
- Department of Biology, San Diego State University, San Diego, CA 92182, USA;
| | - Victor Seguritan
- Department of Biology, San Diego State University, San Diego, CA 9218
| | - Kornelius Zeth
- Unidad de Biofisica (CSIC-UPV/EHU), Barrio Sarriena s/n 48940, Leioa, Vizcaya, SPAIN, and IKERBASQUE, Basque Foundation for Science, Bilbao, Spain;
| | - Torsten Schwede
- (1) Biozentrum, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland; (2) SIB Swiss Institute of Bioinformatics, Klingelbergstrasse 50, 4056 Basel, Switzerland;
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Song C, Weichbrodt C, Salnikov ES, Dynowski M, Forsberg BO, Bechinger B, Steinem C, de Groot BL, Zachariae U, Zeth K. Crystal structure and functional mechanism of a human antimicrobial membrane channel. Proc Natl Acad Sci U S A 2013; 110:4586-91. [PMID: 23426625 PMCID: PMC3607029 DOI: 10.1073/pnas.1214739110] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Multicellular organisms fight bacterial and fungal infections by producing peptide-derived broad-spectrum antibiotics. These host-defense peptides compromise the integrity of microbial cell membranes and thus evade pathways by which bacteria develop rapid antibiotic resistance. Although more than 1,700 host-defense peptides have been identified, the structural and mechanistic basis of their action remains speculative. This impedes the desired rational development of these agents into next-generation antibiotics. We present the X-ray crystal structure as well as solid-state NMR spectroscopy, electrophysiology, and MD simulations of human dermcidin in membranes that reveal the antibiotic mechanism of this major human antimicrobial, found to suppress Staphylococcus aureus growth on the epidermal surface. Dermcidin forms an architecture of high-conductance transmembrane channels, composed of zinc-connected trimers of antiparallel helix pairs. Molecular dynamics simulations elucidate the unusual membrane permeation pathway for ions and show adjustment of the pore to various membranes. Our study unravels the comprehensive mechanism for the membrane-disruptive action of this mammalian host-defense peptide at atomistic level. The results may form a foundation for the structure-based design of peptide antibiotics.
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Affiliation(s)
- Chen Song
- Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Conrad Weichbrodt
- Institute for Organic and Biomolecular Chemistry, Georg August University Göttingen, 37077 Göttingen, Germany
| | - Evgeniy S. Salnikov
- Membrane Biophysics and NMR, Chemistry Institute, Unité Mixte de Recherche 7177, University of Strasbourg and Centre National de la Recherche Scientifique, 67000 Strasbourg, France
| | - Marek Dynowski
- Research and Development, Computing Centre, Freiburg University, 79104 Freiburg, Germany
- Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Björn O. Forsberg
- Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Burkhard Bechinger
- Membrane Biophysics and NMR, Chemistry Institute, Unité Mixte de Recherche 7177, University of Strasbourg and Centre National de la Recherche Scientifique, 67000 Strasbourg, France
| | - Claudia Steinem
- Institute for Organic and Biomolecular Chemistry, Georg August University Göttingen, 37077 Göttingen, Germany
| | - Bert L. de Groot
- Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Ulrich Zachariae
- Scottish Universities' Physics Alliance, School of Physics and Astronomy, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom; and
| | - Kornelius Zeth
- Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
- Unidad de Biofisica, University of Basque Country and Spanish Science Research Council, 48940 Leioa, Vizcaya, Spain
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Forsberg BO, Song C, Weichbrodt C, Dynowski M, Steinem C, Zachariae U, Zeth K, de Groot BL. Channel Crystal Structure and Antimicrobial Mechanism of Dermcidin from Human Skin. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.1359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Zeth K, Fokina O, Forchhammer K. An engineered PII protein variant that senses a novel ligand: atomic resolution structure of the complex with citrate. Acta Crystallogr D Biol Crystallogr 2012; 68:901-8. [PMID: 22868755 DOI: 10.1107/s0907444912016447] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 04/16/2012] [Indexed: 11/10/2022]
Abstract
PII proteins are central signal processing units for the regulation of nitrogen metabolism in bacteria, archaea and plants. They act in response to cellular energy, carbon and nitrogen availability. The central metabolites ATP, ADP and 2-oxoglutarate, which indicate cellular energy and carbon/nitrogen abundance, bind in a highly organized manner to PII and induce effector-molecule-dependent conformational states of the T-loop. Depending on these states, PII proteins bind and modulate the activity of various regulatory targets. A mutant variant of the Synechococcus elongatus PII protein (PII-I86N) has been identified to have impaired 2-oxoglutarate binding. Here, the PII-I86N variant was cocrystallized in the presence of ATP, magnesium and citrate and its structure was solved at a resolution of 1.05 Å. The PII-I86N variant bound citrate in place of 2-oxoglutarate. Citrate binding is mediated primarily by interactions with the ATP-coordinated magnesium ion and the backbone atoms of the T-loop. Citrate binding rearranges the conformation of the T-loop and, consistent with this, citrate suppresses the binding of PII-I86N to an NAG kinase variant, which is similar to the suppression of PII-NAG kinase complex formation by 2-OG. Based on the structures of 2-OG and citrate, homocitrate was suggested as a third ligand and an efficient response towards this molecule with different functional properties was observed. Together, these data provide a first glimpse of a genetically engineered PII variant that senses a new effector molecule.
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Affiliation(s)
- Kornelius Zeth
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany.
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Abstract
Yersinia pestis produces and secretes a toxin named pesticin that kills related bacteria of the same niche. Uptake of the bacteriocin is required for activity in the periplasm leading to hydrolysis of peptidoglycan. To understand the uptake mechanism and to investigate the function of pesticin, we combined crystal structures of the wild type enzyme, active site mutants, and a chimera protein with in vivo and in vitro activity assays. Wild type pesticin comprises an elongated N-terminal translocation domain, the intermediate receptor binding domain, and a C-terminal activity domain with structural analogy to lysozyme homologs. The full-length protein is toxic to bacteria when taken up to the target site via the outer or the inner membrane. Uptake studies of deletion mutants in the translocation domain demonstrate their critical size for import. To further test the plasticity of pesticin during uptake into bacterial cells, the activity domain was replaced by T4 lysozyme. Surprisingly, this replacement resulted in an active chimera protein that is not inhibited by the immunity protein Pim. Activity of pesticin and the chimera protein was blocked through introduction of disulfide bonds, which suggests unfolding as the prerequisite to gain access to the periplasm. Pesticin, a muramidase, was characterized by active site mutations demonstrating a similar but not identical residue pattern in comparison with T4 lysozyme.
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Affiliation(s)
- Silke I Patzer
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
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Ferris HU, Dunin-Horkawicz S, Hornig N, Hulko M, Martin J, Schultz JE, Zeth K, Lupas AN, Coles M. Mechanism of regulation of receptor histidine kinases. Structure 2012; 20:56-66. [PMID: 22244755 DOI: 10.1016/j.str.2011.11.014] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 11/16/2011] [Accepted: 11/17/2011] [Indexed: 02/02/2023]
Abstract
Bacterial transmembrane receptors regulate an intracellular catalytic output in response to extracellular sensory input. To investigate the conformational changes that relay the regulatory signal, we have studied the HAMP domain, a ubiquitous intracellular module connecting input to output domains. HAMP forms a parallel, dimeric, four-helical coiled coil, and rational substitutions in our model domain (Af1503 HAMP) induce a transition in its interhelical packing, characterized by axial rotation of all four helices (the gearbox signaling model). We now illustrate how these conformational changes are propagated to a downstream domain by fusing Af1503 HAMP variants to the DHp domain of EnvZ, a bacterial histidine kinase. Structures of wild-type and mutant constructs are correlated with ligand response in vivo, clearly associating them with distinct signaling states. We propose that altered recognition of the catalytic domain by DHp, rather than a shift in position of the phospho-accepting histidine, forms the basis for regulation of kinase activity.
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Affiliation(s)
- Hedda U Ferris
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, 72076 Tübingen, Germany
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28
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Usón I, Patzer SI, Rodríguez DD, Braun V, Zeth K. The crystal structure of the dimeric colicin M immunity protein displays a 3D domain swap. J Struct Biol 2012; 178:45-53. [PMID: 22366279 DOI: 10.1016/j.jsb.2012.02.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 01/16/2012] [Accepted: 02/06/2012] [Indexed: 11/19/2022]
Abstract
Bacteriocins are proteins secreted by many bacterial cells to kill related bacteria of the same niche. To avoid their own suicide through reuptake of secreted bacteriocins, these bacteria protect themselves by co-expression of immunity proteins in the compartment of colicin destination. In Escherichia coli the colicin M (Cma) is inactivated by the interaction with the Cma immunity protein (Cmi). We have crystallized and solved the structure of Cmi at a resolution of 1.95Å by the recently developed ab initio phasing program ARCIMBOLDO. The monomeric structure of the mature 10kDa protein comprises a long N-terminal α-helix and a four-stranded C-terminal β-sheet. Dimerization of this fold is mediated by an extended interface of hydrogen bond interactions between the α-helix and the four-stranded β-sheet of the symmetry related molecule. Two intermolecular disulfide bridges covalently connect this dimer to further lock this complex. The Cmi protein resembles an example of a 3D domain swapping being stalled through physical linkage. The dimer is a highly charged complex with a significant surplus of negative charges presumably responsible for interactions with Cma. Dimerization of Cmi was also demonstrated to occur in vivo. Although the Cmi-Cma complex is unique among bacteria, the general fold of Cmi is representative for a class of YebF-like proteins which are known to be secreted into the external medium by some Gram-negative bacteria.
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Affiliation(s)
- Isabel Usón
- Instituto de Biología Molecular de Barcelona, Barcelona, Spain
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29
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Song C, Bordignon E, Dynowski M, Markov G, de Groot BL, Zachariae U, Zeth K. Structure and Dynamics of the Human Antimicrobial Peptide Dermcidin Oligomer: It is an Ion Channel. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.2584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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Pesek J, Büchler R, Albrecht R, Boland W, Zeth K. Structure and mechanism of iron translocation by a Dps protein from Microbacterium arborescens. J Biol Chem 2011; 286:34872-82. [PMID: 21768097 PMCID: PMC3186433 DOI: 10.1074/jbc.m111.246108] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dps (DNA protection during starvation) enzymes are a major class of dodecameric proteins that bacteria use to detoxify their cytosol through the uptake of reactive iron species. In the stationary growth phase of bacteria, Dps enzymes are primarily used to protect DNA by biocrystallization. To characterize the wild type Dps protein from Microbacterium arborescens that displays additional catalytic functions (amide hydrolysis and synthesis), we determined the crystal structure to a resolution of 2.05 Å at low iron content. The structure shows a single iron at the ferroxidase center coordinated by an oxo atom, one water molecule, and three ligating residues. An iron-enriched protein structure was obtained at 2 Å and shows the stepwise uptake of two hexahydrated iron atoms moving along channels at the 3-fold axis before a restriction site inside the channels requires removal of the hydration sphere. Supporting biochemical data provide insight into the regulation of this acylamino acid hydrolase. Moreover, the peroxidase activity of the protein was determined. The influence of iron and siderophores on the expression of acylamino acid hydrolase was monitored during several stages of cell growth. Altogether our data provide an interesting view of an unusual Dps-like enzyme evolutionarily located apart from the large Dps sequence clusters.
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Affiliation(s)
- Jelena Pesek
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, D-07745 Jena, Germany
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Abstract
In Escherichia coli, a multicomponent BAM (β-barrel assembly machinery) complex is responsible for recognition and assembly of outer membrane β-barrel proteins. The functionality of BAM in protein biogenesis is mainly orchestrated through the presence of two essential components, BamA and BamD. Here, we present crystal structures of four lipoproteins (BamB-E). Monomeric BamB and BamD proteins display scaffold architectures typically implied in transient protein interactions. BamB is a β-propeller protein comprising eight WD40 repeats. BamD shows an elongated fold on the basis of five tetratricopeptide repeats, three of which form the scaffold for protein recognition. The rod-shaped BamC protein has evolved through the gene duplication of two conserved domains known to mediate protein interactions in structurally related complexes. By contrast, the dimeric BamE is formed through a domain swap and indicates fold similarity to the β-lactamase inhibitor protein family, possibly integrating cell wall stability in BAM function. Structural and biochemical data show evidence for the specific recognition of amphipathic sequences through the tetratricopeptide repeat architecture of BamD. Collectively, our data advance the understanding of the BAM complex and highlight the functional importance of BamD in amphipathic outer membrane β-barrel protein motif recognition and protein delivery.
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Affiliation(s)
- Reinhard Albrecht
- From the Department of Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, Tübingen 72076, Germany
| | - Kornelius Zeth
- From the Department of Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, Tübingen 72076, Germany
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Mager F, Gessmann D, Nussberger S, Zeth K. Functional refolding and characterization of two Tom40 isoforms from human mitochondria. J Membr Biol 2011; 242:11-21. [PMID: 21717124 DOI: 10.1007/s00232-011-9372-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 05/24/2011] [Indexed: 11/26/2022]
Abstract
Tom40 proteins represent an essential class of molecules which facilitate translocation of unfolded proteins from the cytosol into the mitochondrial intermembrane space. They are part of a high-molecular mass complex that forms the protein-conducting channel in outer mitochondrial membranes. This study concerns the recombinant expression, purification and folding of amino-terminally truncated variants of the two human Tom40 isoforms for structural biology experiments. Both CD and FTIR secondary structure analysis revealed a dominant beta-sheet structure and a short alpha-helical part for both proteins together with a high thermal stability. Two secondary structure elements can be denatured independently. Reconstitution of the recombinant protein into planar lipid bilayers demonstrated ion channel activity similar to Tom40 purified from Neurospora crassa mitochondrial membranes, but conductivity fingerprints differ from the structurally closely related VDAC proteins.
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Affiliation(s)
- Frauke Mager
- Biophysics Department, Institute of Biology, University of Stuttgart, Germany
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Ferris HU, Dunin-Horkawicz S, Mondéjar LG, Hulko M, Hantke K, Martin J, Schultz JE, Zeth K, Lupas AN, Coles M. The mechanisms of HAMP-mediated signaling in transmembrane receptors. Structure 2011; 19:378-85. [PMID: 21397188 DOI: 10.1016/j.str.2011.01.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 12/06/2010] [Accepted: 01/06/2011] [Indexed: 11/29/2022]
Abstract
HAMP domains mediate signal transduction in over 7500 enzyme-coupled receptors represented in all kingdoms of life. The HAMP domain of the putative archaeal receptor Af1503 has a parallel, dimeric, four-helical coiled coil structure, but with unusual core packing, related to canonical packing by concerted axial rotation of the helices. This has led to the gearbox model for signal transduction, whereby the alternate packing modes correspond to signaling states. Here we present structures of a series of Af1503 HAMP variants. We show that substitution of a conserved small side chain within the domain core (A291) for larger residues induces a gradual transition in packing mode, involving both changes in helix rotation and bundle shape, which are most prominent at the C-terminal, output end of the domain. These are correlated with activity and ligand response in vitro and in vivo by incorporating Af1503 HAMP into mycobacterial adenylyl cyclase assay systems.
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Affiliation(s)
- Hedda U Ferris
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, 72076 Tübingen, Germany
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Zeth K, Pechlivanis M, Samol A, Pleiser S, Vonrhein C, Kerkhoff E. Molecular basis of actin nucleation factor cooperativity: crystal structure of the Spir-1 kinase non-catalytic C-lobe domain (KIND)•formin-2 formin SPIR interaction motif (FSI) complex. J Biol Chem 2011; 286:30732-30739. [PMID: 21705804 DOI: 10.1074/jbc.m111.257782] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The distinct actin nucleation factors of the Spir and formin subgroup families cooperate in actin nucleation. The Spir/formin cooperativity has been identified to direct two essential steps in mammalian oocyte maturation, the asymmetric spindle positioning and polar body extrusion during meiosis. Understanding the nature and regulation of the Spir/Fmn cooperation is an important requirement to comprehend mammalian reproduction. Recently we dissected the structural elements of the Spir and Fmn family proteins, which physically link the two actin nucleation factors. The trans-regulatory interaction is mediated by the Spir kinase non-catalytic C-lobe domain (KIND) and the C-terminal formin Spir interaction motif (FSI). The interaction inhibits formin nucleation activity and enhances the Spir activity. To get insights into the molecular mechanism of the Spir/Fmn interaction, we determined the crystal structure of the KIND domain alone and in complex with the C-terminal Fmn-2 FSI peptide. Together they confirm the proposed structural homology of the KIND domain to the protein kinase fold and reveal the basis of the Spir/formin interaction. The complex structure showed a large interface with conserved and positively charged residues of the Fmn FSI peptide mediating major contacts to an acidic groove on the surface of KIND. Protein interaction studies verified the electrostatic nature of the interaction. The data presented here provide the molecular basis of the Spir/formin interaction and give a first structural view into the mechanisms of actin nucleation factor cooperativity.
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Affiliation(s)
- Kornelius Zeth
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Markos Pechlivanis
- Department of Neurology, Molecular Cell Biology Laboratory, Bavarian Genome Research Network (BayGene), University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Annette Samol
- Department of Neurology, Molecular Cell Biology Laboratory, Bavarian Genome Research Network (BayGene), University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Sandra Pleiser
- Department of Neurology, Molecular Cell Biology Laboratory, Bavarian Genome Research Network (BayGene), University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Clemens Vonrhein
- Global Phasing Limited, Sheraton House, Castle Park, Cambridge CB3 0AX, United Kingdom
| | - Eugen Kerkhoff
- Department of Neurology, Molecular Cell Biology Laboratory, Bavarian Genome Research Network (BayGene), University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
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35
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Römer C, Patzer SI, Albrecht R, Zeth K, Braun V. Expression, purification and crystallization of the Cmi immunity protein from Escherichia coli. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:517-520. [PMID: 21505256 PMCID: PMC3080165 DOI: 10.1107/s1744309111006737] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 02/22/2011] [Indexed: 05/30/2023]
Abstract
Many bacteria kill related bacteria by secretion of bacteriocins. In Escherichia coli, the colicin M protein kills E. coli after uptake into the periplasm. Self-protection from destruction is provided by the co-expressed immunity protein. The colicin M immunity protein (Cmi) was cloned, overexpressed and purified to homogeneity. The correct fold of purified Cmi was analyzed by activity tests and circular-dichroism spectroscopy. Crystallization trials yielded crystals, one of which diffracted to a resolution of 1.9 Å in the orthorhombic space group C222(1). The crystal packing, with unit-cell parameters a = 66.02, b = 83.47, c = 38.30 Å, indicated the presence of one monomer in the asymmetric unit with a solvent content of 53%.
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Affiliation(s)
- Christin Römer
- Department for Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, D-72076 Tübingen, Germany
| | - Silke I. Patzer
- Department for Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, D-72076 Tübingen, Germany
| | - Reinhard Albrecht
- Department for Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, D-72076 Tübingen, Germany
| | - Kornelius Zeth
- Department for Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, D-72076 Tübingen, Germany
| | - Volkmar Braun
- Department for Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, D-72076 Tübingen, Germany
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36
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Abstract
Colicin M (Cma) is specifically imported into the periplasm of Escherichia coli and kills the cells. Killing depends on the periplasmic peptidyl prolyl cis-trans isomerase/chaperone FkpA. To identify the Cma prolyl bonds targeted by FkpA, we replaced the 15 proline residues individually with alanine. Seven mutant proteins were fully active; Cma(P129A), Cma(P176A), and Cma(P260A) displayed 1%, and Cma(P107A) displayed 10% of the wild-type activity. Cma(P107A), Cma(P129A), and Cma(P260A), but not Cma(P176A), killed cells after entering the periplasm via osmotic shock, indicating that the former mutants were translocation-deficient; Cma(P129A) did not bind to the FhuA outer membrane receptor. The crystal structures of Cma and Cma(P176A) were identical, excluding inactivation of the activity domain located far from Pro-176. In a new peptidyl prolyl cis-trans isomerase assay, FkpA isomerized the Cma prolyl bond in peptide Phe-Pro-176 at a high rate, but Lys-Pro-107 and Leu-Pro-260 isomerized at only <10% of that rate. The four mutant proteins secreted into the periplasm via a fused signal sequence were toxic but much less than wild-type Cma. Wild-type and mutant Cma proteins secreted or translocated across the outer membrane by energy-coupled import or unspecific osmotic shock were only active in the presence of FkpA. We propose that Cma unfolds during transfer across the outer or cytoplasmic membrane and refolds to the active form in the periplasm assisted by FkpA. Weak refolding of Cma(P176A) would explain its low activity in all assays. Of the four proline residues identified as being important for Cma activity, Phe-Pro-176 is most likely targeted by FkpA.
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Affiliation(s)
- Stephanie Helbig
- Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
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37
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Albrecht R, Zeth K. Crystallization and preliminary X-ray data collection of the Escherichia coli lipoproteins BamC, BamD and BamE. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1586-90. [PMID: 21139201 DOI: 10.1107/s1744309110034160] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 08/24/2010] [Indexed: 11/10/2022]
Abstract
In Escherichia coli, the β-barrel assembly machinery (or BAM complex) mediates the recognition, insertion and assembly of outer membrane proteins. The complex consists of the integral membrane protein BamA (an Omp85-family member) and the lipoproteins BamB, BamC, BamD and BamE. The purification and crystallization of BamC, BamD and BamE, each lacking the N-terminal membrane anchor, is described. While the smallest protein BamE yielded crystals under conventional conditions, BamD only crystallized after stabilization with urea. Full-length BamC did not crystallize, but was cleaved by subtilisin into two domains which were subsequently crystallized independently. High-resolution data were acquired from all proteins.
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Affiliation(s)
- Reinhard Albrecht
- Max-Planck-Institut für Entwicklungsbiologie, Department of Protein Evolution, Spemannstrasse 35, D-72076 Tübingen, Germany
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Arnold T, Zeth K, Linke D. Omp85 from the thermophilic cyanobacterium Thermosynechococcus elongatus differs from proteobacterial Omp85 in structure and domain composition. J Biol Chem 2010; 285:18003-15. [PMID: 20351097 PMCID: PMC2878562 DOI: 10.1074/jbc.m110.112516] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 03/26/2010] [Indexed: 12/03/2022] Open
Abstract
Omp85 proteins are essential proteins located in the bacterial outer membrane. They are involved in outer membrane biogenesis and assist outer membrane protein insertion and folding by an unknown mechanism. Homologous proteins exist in eukaryotes, where they mediate outer membrane assembly in organelles of endosymbiotic origin, the mitochondria and chloroplasts. We set out to explore the homologous relationship between cyanobacteria and chloroplasts, studying the Omp85 protein from the thermophilic cyanobacterium Thermosynechococcus elongatus. Using state-of-the art sequence analysis and clustering methods, we show how this protein is more closely related to its chloroplast homologue Toc75 than to proteobacterial Omp85, a finding supported by single channel conductance measurements. We have solved the structure of the periplasmic part of the protein to 1.97 A resolution, and we demonstrate that in contrast to Omp85 from Escherichia coli the protein has only three, not five, polypeptide transport-associated (POTRA) domains, which recognize substrates and generally interact with other proteins in bigger complexes. We model how these POTRA domains are attached to the outer membrane, based on the relationship of Omp85 to two-partner secretion system proteins, which we show and analyze. Finally, we discuss how Omp85 proteins with different numbers of POTRA domains evolved, and evolve to this day, to accomplish an increasing number of interactions with substrates and helper proteins.
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Affiliation(s)
- Thomas Arnold
- From Department I, Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Kornelius Zeth
- From Department I, Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Dirk Linke
- From Department I, Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
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Fokina O, Chellamuthu VR, Zeth K, Forchhammer K. A novel signal transduction protein P(II) variant from Synechococcus elongatus PCC 7942 indicates a two-step process for NAGK-P(II) complex formation. J Mol Biol 2010; 399:410-21. [PMID: 20399792 DOI: 10.1016/j.jmb.2010.04.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 03/17/2010] [Accepted: 04/13/2010] [Indexed: 11/15/2022]
Abstract
P(II) signal transduction proteins are highly conserved in bacteria, archaea and plants and have key functions in coordination of central metabolism by integrating signals from the carbon, nitrogen and energy status of the cell. In the cyanobacterium Synechococcus elongatus PCC 7942, P(II) binds ATP and 2-oxoglutarate (2-OG) in a synergistic manner, with the ATP binding sites also accepting ADP. Depending on its effector molecule binding status, P(II) (from this cyanobacterium and other oxygenic phototrophs) complexes and regulates the arginine-controlled enzyme of the cyclic ornithine pathway, N-acetyl-l-glutamate kinase (NAGK), to control arginine biosynthesis. To gain deeper insights into the process of P(II) binding to NAGK, we searched for P(II) variants with altered binding characteristics and found P(II) variants I86N and I86T to be able to bind to an NAGK variant (R233A) that was previously shown to be unable to bind wild-type P(II) protein. Analysis of interactions between these P(II) variants and wild-type NAGK as well as with the NAGK R233A variant suggested that the P(II) I86N variant was a superactive NAGK binder. To reveal the structural basis of this property, we solved the crystal structure of the P(II) I86N variant at atomic resolution. The large T-loop, which prevails in most receptor interactions of P(II) proteins, is present in a tightly bended conformation that mimics the T-loop of S. elongatus P(II) after having latched onto NAGK. Moreover, both P(II) I86 variants display a specific defect in 2-OG binding, implying a role of residue I86 in 2-OG binding. We propose a two-step model for the mechanism of P(II)-NAGK complex formation: in an initiating step, a contact between R233 of NAGK and E85 of P(II) initiates the bending of the extended T-loop of P(II), followed by a second step, where a bended T-loop deeply inserts into the NAGK clefts to form the tight complex.
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Affiliation(s)
- Oleksandra Fokina
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin der Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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40
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Alvarez BH, Gruber M, Ursinus A, Dunin-Horkawicz S, Lupas AN, Zeth K. A transition from strong right-handed to canonical left-handed supercoiling in a conserved coiled-coil segment of trimeric autotransporter adhesins. J Struct Biol 2010; 170:236-45. [PMID: 20178846 DOI: 10.1016/j.jsb.2010.02.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 02/16/2010] [Accepted: 02/16/2010] [Indexed: 11/30/2022]
Abstract
Trimeric autotransporter adhesins (TAAs) represent an important class of pathogenicity factors in proteobacteria. Their defining feature is a conserved membrane anchor, which forms a 12-stranded beta-barrel through the outer membrane. The proteins are translocated through the pore of this barrel and, once export is complete, the pore is occluded by a three-stranded coiled coil with canonical heptad (7/2) sequence periodicity. In many TAAs this coiled coil is extended by a segment of varying length, which has pentadecad (15/4) periodicity. We used X-ray crystallography and biochemical methods to analyze the transition between these two periodicities in the coiled-coil stalk of the Yersinia adhesin YadA. Our results show how the strong right-handed supercoil of the 15/4-periodic part locally undergoes further over-winding to 19/5, before switching at a fairly constant rate over 14 residues to the canonical left-handed supercoil of the 7/2-periodic part. The transition region contains two YxD motifs, which are characteristic for right-handed coiled-coil segments of TAAs. This novel coiled-coil motif forms a defined network of inter- and intrahelical hydrogen bonds, thus serving as a structural determinant. Supercoil fluctuations have hitherto been described in coiled coils whose main sequence periodicity is disrupted locally by discontinuities. Here we present the first detailed analysis of two fundamentally different coiled-coil periodicities being accommodated in the same structure.
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Affiliation(s)
- Birte Hernandez Alvarez
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, 72076 Tübingen, Germany
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42
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Bleicken S, Classen M, Padmavathi PVL, Ishikawa T, Zeth K, Steinhoff HJ, Bordignon E. Molecular details of Bax activation, oligomerization, and membrane insertion. J Biol Chem 2009; 285:6636-47. [PMID: 20008353 DOI: 10.1074/jbc.m109.081539] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bax and Bid are pro-apoptotic members of the Bcl-2 protein family. Upon cleavage by caspase-8, Bid activates Bax. Activated Bax inserts into the mitochondrial outer membrane forming oligomers which lead to membrane poration, release of cytochrome c, and apoptosis. The detailed mechanism of Bax activation and the topology and composition of the oligomers are still under debate. Here molecular details of Bax activation and oligomerization were obtained by application of several biophysical techniques, including atomic force microscopy, cryoelectron microscopy, and particularly electron paramagnetic resonance (EPR) spectroscopy performed on spin-labeled Bax. Incubation with detergents, reconstitution, and Bid-triggered insertion into liposomes were found to be effective in inducing Bax oligomerization. Bid was shown to activate Bax independently of the stoichiometric ratio, suggesting that Bid has a catalytic function and that the interaction with Bax is transient. The formation of a stable dimerization interface involving two Bcl-2 homology 3 (BH3) domains was found to be the nucleation event for Bax homo-oligomerization. Based on intermolecular distance determined by EPR, a model of six adjacent Bax molecules in the oligomer is presented where the hydrophobic hairpins (helices alpha5 and alpha6) are equally spaced in the membrane and the two BH3 domains are in close vicinity in the dimer interface, separated by >5 nm from the next BH3 pairs.
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Affiliation(s)
- Stephanie Bleicken
- Department of Membrane Biochemistry, Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
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43
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Schuenemann VJ, Kralik SM, Albrecht R, Spall SK, Truscott KN, Dougan DA, Zeth K. Structural basis of N‐end rule substrate recognition in
Escherichia coli
by the ClpAP adaptor protein ClpS. EMBO Rep 2009. [DOI: 10.1038/embor.2009.107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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44
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Schuenemann VJ, Kralik SM, Albrecht R, Spall SK, Truscott KN, Dougan DA, Zeth K. Structural basis of N-end rule substrate recognition in Escherichia coli by the ClpAP adaptor protein ClpS. EMBO Rep 2009; 10:508-14. [PMID: 19373253 DOI: 10.1038/embor.2009.62] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Revised: 03/02/2009] [Accepted: 03/03/2009] [Indexed: 11/09/2022] Open
Abstract
In Escherichia coli, the ClpAP protease, together with the adaptor protein ClpS, is responsible for the degradation of proteins bearing an amino-terminal destabilizing amino acid (N-degron). Here, we determined the three-dimensional structures of ClpS in complex with three peptides, each having a different destabilizing residue--Leu, Phe or Trp--at its N terminus. All peptides, regardless of the identity of their N-terminal residue, are bound in a surface pocket on ClpS in a stereo-specific manner. Several highly conserved residues in this binding pocket interact directly with the backbone of the N-degron peptide and hence are crucial for the binding of all N-degrons. By contrast, two hydrophobic residues define the volume of the binding pocket and influence the specificity of ClpS. Taken together, our data suggest that ClpS has been optimized for the binding and delivery of N-degrons containing an N-terminal Phe or Leu.
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Affiliation(s)
- Verena J Schuenemann
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, Tübingen D-72076, Germany
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45
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Abstract
Pro-apoptotic Bax is a soluble and monomeric protein under normal physiological conditions. Upon its activation substantial structural rearrangements occur: The protein inserts into the mitochondrial outer membrane and forms higher molecular weight oligomers. Subsequently, the cells can undergo apoptosis. In our studies, we focused on the structural rearrangements of Bax during oligomerization and on the protein stability. Both protein conformations exhibit high stability against thermal denaturation, chemically induced unfolding and proteolytic processing. The oligomeric protein is stable up to 90 degrees C as well as in solutions of 8 M urea or 6 M guanidinium hydrochloride. Helix 9 appears accessible in the monomer but hidden in the oligomer assessed by proteolysis. Tryptophan fluorescence indicates that the environment of the C-terminal protein half becomes more apolar upon oligomerization, whereas the loop region between helices 1 and 2 gets solvent exposed.
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Affiliation(s)
- Stephanie Bleicken
- Department of Membrane Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
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46
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Abstract
Colicins are plasmid-encoded toxic proteins produced by Escherichia coli strains to kill other E. coli strains that lack the corresponding immunity protein. Colicins intrude into the host cell by exploiting existing transport, diffusion, or efflux systems. We have traced the way colicin S4 takes to execute its function and show that it interacts specifically with OmpW, OmpF, and the Tol system before it inserts its pore-forming domain into the cytoplasmic membrane. The common structural architecture of colicins comprises a translocation, a receptor-binding, and an activity domain. We have solved the crystal structure of colicin S4 to a resolution of 2.5 A, which shows a remarkably compact domain arrangement of four independent domains, including a unique domain duplication of the receptor-binding domain. Finally, we have determined the residues responsible for binding to the receptor OmpW by mutating exposed charged residues in one or both receptor-binding domains.
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Affiliation(s)
- Thomas Arnold
- Department I, Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
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47
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Asen I, Djuranovic S, Lupas AN, Zeth K. Crystal structure of SpoVT, the final modulator of gene expression during spore development in Bacillus subtilis. J Mol Biol 2008; 386:962-75. [PMID: 18996130 DOI: 10.1016/j.jmb.2008.10.061] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 10/21/2008] [Accepted: 10/22/2008] [Indexed: 10/21/2022]
Abstract
Endospore formation in Bacillus subtilis is orchestrated by five developmental sigma factors and further modulated by several auxiliary transcription factors. One of these, SpoVT, regulates forespore-specific sigma(G)-dependent genes and plays a key role in the final stages of spore formation. We have determined the crystal structure of the isolated C-terminal domain of SpoVT at 1.5 A by experimental phasing techniques and used this model to solve the structure of the full-length SpoVT at 2.6 A by molecular replacement. SpoVT is a tetramer that shows an overall significant distortion mediated by electrostatic interactions. Two monomers dimerize via the highly charged N-terminal domains to form swapped-hairpin beta-barrels. These asymmetric dimers further tetramerize through the formation of mixed helix bundles between their C-terminal domains, which themselves fold as GAF (cGMP-specific and cGMP-stimulated phosphodiesterases, Anabaena adenylate cyclases, and Escherichia coli FhlA) domains. The combination of a swapped-hairpin beta-barrel with a GAF domain represents a novel domain architecture in transcription factors. The occurrence of SpoVT homologs throughout Bacilli and Clostridia demonstrates the ancestral origin of this factor in sporulation.
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Affiliation(s)
- Iris Asen
- Department of Membrane Biochemistry, Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
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48
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Zeth K, Römer C, Patzer SI, Braun V. Crystal structure of colicin M, a novel phosphatase specifically imported by Escherichia coli. J Biol Chem 2008; 283:25324-25331. [PMID: 18640984 PMCID: PMC2533080 DOI: 10.1074/jbc.m802591200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 06/23/2008] [Indexed: 11/06/2022] Open
Abstract
Colicins are cytotoxic proteins secreted by certain strains of Escherichia coli. Colicin M is unique among these toxins in that it acts in the periplasm and specifically inhibits murein biosynthesis by hydrolyzing the pyrophosphate linkage between bactoprenol and the murein precursor. We crystallized colicin M and determined the structure at 1.7A resolution using x-ray crystallography. The protein has a novel structure composed of three domains with distinct functions. The N-domain is a short random coil and contains the exposed TonB box. The central domain includes a hydrophobic alpha-helix and binds presumably to the FhuA receptor. The C-domain is composed of a mixed alpha/beta-fold and forms the phosphatase. The architectures of the individual modules show no similarity to known structures. Amino acid replacements in previously isolated inactive colicin M mutants are located in the phosphatase domain, which contains a number of surface-exposed residues conserved in predicted bacteriocins of other bacteria. The novel phosphatase domain displays no sequence similarity to known phosphatases. The N-terminal and central domains are not conserved among bacteriocins, which likely reflect the distinct import proteins required for the uptake of the various bacteriocins. The homology pattern supports our previous proposal that colicins evolved by combination of distinct functional domains.
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Affiliation(s)
- Kornelius Zeth
- Max Planck Institute for Developmental Biology, Department of Protein Evolution, D-72076 Tübingen, Germany
| | - Christin Römer
- Max Planck Institute for Developmental Biology, Department of Protein Evolution, D-72076 Tübingen, Germany
| | - Silke I Patzer
- Max Planck Institute for Developmental Biology, Department of Protein Evolution, D-72076 Tübingen, Germany
| | - Volkmar Braun
- Max Planck Institute for Developmental Biology, Department of Protein Evolution, D-72076 Tübingen, Germany.
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49
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Szczesny P, Linke D, Ursinus A, Bär K, Schwarz H, Riess TM, Kempf VAJ, Lupas AN, Martin J, Zeth K. Structure of the head of the Bartonella adhesin BadA. PLoS Pathog 2008; 4:e1000119. [PMID: 18688279 PMCID: PMC2483945 DOI: 10.1371/journal.ppat.1000119] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 07/10/2008] [Indexed: 11/18/2022] Open
Abstract
Trimeric autotransporter adhesins (TAAs) are a major class of proteins by which pathogenic proteobacteria adhere to their hosts. Prominent examples include Yersinia YadA, Haemophilus Hia and Hsf, Moraxella UspA1 and A2, and Neisseria NadA. TAAs also occur in symbiotic and environmental species and presumably represent a general solution to the problem of adhesion in proteobacteria. The general structure of TAAs follows a head-stalk-anchor architecture, where the heads are the primary mediators of attachment and autoagglutination. In the major adhesin of Bartonella henselae, BadA, the head consists of three domains, the N-terminal of which shows strong sequence similarity to the head of Yersinia YadA. The two other domains were not recognizably similar to any protein of known structure. We therefore determined their crystal structure to a resolution of 1.1 A. Both domains are beta-prisms, the N-terminal one formed by interleaved, five-stranded beta-meanders parallel to the trimer axis and the C-terminal one by five-stranded beta-meanders orthogonal to the axis. Despite the absence of statistically significant sequence similarity, the two domains are structurally similar to domains from Haemophilus Hia, albeit in permuted order. Thus, the BadA head appears to be a chimera of domains seen in two other TAAs, YadA and Hia, highlighting the combinatorial evolutionary strategy taken by pathogens.
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Affiliation(s)
- Pawel Szczesny
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
- Department of Bioinformatics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Dirk Linke
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Astrid Ursinus
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Kerstin Bär
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Heinz Schwarz
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Tanja M. Riess
- Institut für Medizinische Mikrobiologie und Hygiene, Eberhard-Karls-Universität, Tübingen, Germany
| | - Volkhard A. J. Kempf
- Institut für Medizinische Mikrobiologie und Hygiene, Eberhard-Karls-Universität, Tübingen, Germany
| | - Andrei N. Lupas
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
- * E-mail:
| | - Jörg Martin
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Kornelius Zeth
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
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50
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Meins T, Vonrhein C, Zeth K. Crystallization and preliminary X-ray crystallographic studies of human voltage-dependent anion channel isoform I (HVDAC1). Acta Crystallogr Sect F Struct Biol Cryst Commun 2008; 64:651-5. [PMID: 18607100 DOI: 10.1107/s174430910801676x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Accepted: 06/02/2008] [Indexed: 11/10/2022]
Abstract
The major channel by which metabolites can pass through the outer mitochondrial membrane is formed by the voltage-dependent anion-channel (VDAC) family. Functionally, VDAC is involved in the limited exchange of ATP, ADP and small hydrophilic molecules across the outer membrane. Moreover, there is compelling evidence that VDAC isoforms in mammals may act in the cross-talk between mitochondria and the cytoplasm by direct interaction with enzymes involved in energy metabolism and proteins involved in mitochondrial-induced apoptosis. To obtain a high-resolution structure of this channel, human VDAC protein isoform I was overproduced in Escherichia coli. After refolding and testing the correct fold using circular dichroism, a subsequent broad-range screening in different detergents resulted in a variety of crystals which diffracted to 3.5 A resolution. The crystal lattice belongs to the trigonal space group P321, with unit-cell parameters a = 78.9, c = 165.7 A and one monomer in the asymmetric unit.
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Affiliation(s)
- Thomas Meins
- Max Planck Institute of Biochemistry, Department of Membrane Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
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