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Madsen JJ, Yu W. Dynamic Nature of Staphylococcus aureus Type I Signal Peptidases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.23.576923. [PMID: 38328037 PMCID: PMC10849702 DOI: 10.1101/2024.01.23.576923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Molecular dynamics simulations are used to interrogate the dynamic nature of Staphylococcus aureus Type I signal peptidases, SpsA and SpsB, including the impact of the P29S mutation of SpsB. Fluctuations and plasticity- rigidity characteristics vary among the proteins, particularly in the extracellular domain. Intriguingly, the P29S mutation, which influences susceptibility to arylomycin antibiotics, affect the mechanically coupled motions in SpsB. The integrity of the active site is crucial for catalytic competency, and variations in sampled structural conformations among the proteins are consistent with diverse peptidase capabilities. We also explored the intricate interactions between the proteins and the model S. aureus membrane. It was observed that certain membrane-inserted residues in the loop around residue 50 (50s) and C-terminal loops, beyond the transmembrane domain, give rise to direct interactions with lipids in the bilayer membrane. Our findings are discussed in the context of functional knowledge about these signal peptidases, offering additional understanding of dynamic aspects relevant to some cellular processes with potential implications for drug targeting strategies.
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Affiliation(s)
- Jesper J. Madsen
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States of America
- Center for Global Health and Infectious Diseases Research, Global and Planetary Health, College of Public Health, University of South Florida, Tampa, Florida 33612, United States of America
| | - Wenqi Yu
- Department of Molecular Biosciences, College of Arts and Sciences, University of South Florida, Tampa, Florida 33612, United States of America
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Rozov SM, Deineko EV. Increasing the Efficiency of the Accumulation of Recombinant Proteins in Plant Cells: The Role of Transport Signal Peptides. PLANTS (BASEL, SWITZERLAND) 2022; 11:2561. [PMID: 36235427 PMCID: PMC9572730 DOI: 10.3390/plants11192561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
The problem with increasing the yield of recombinant proteins is resolvable using different approaches, including the transport of a target protein to cell compartments with a low protease activity. In the cell, protein targeting involves short-signal peptide sequences recognized by intracellular protein transport systems. The main systems of the protein transport across membranes of the endoplasmic reticulum and endosymbiotic organelles are reviewed here, as are the major types and structure of the signal sequences targeting proteins to the endoplasmic reticulum and its derivatives, to plastids, and to mitochondria. The role of protein targeting to certain cell organelles depending on specific features of recombinant proteins and the effect of this targeting on the protein yield are discussed, in addition to the main directions of the search for signal sequences based on their primary structure. This knowledge makes it possible not only to predict a protein localization in the cell but also to reveal the most efficient sequences with potential biotechnological utility.
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Antimicrobial Activity of Rhenium Di- and Tricarbonyl Diimine Complexes: Insights on Membrane-Bound S. aureus Protein Binding. Pharmaceuticals (Basel) 2022; 15:ph15091107. [PMID: 36145328 PMCID: PMC9501577 DOI: 10.3390/ph15091107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/31/2022] [Accepted: 08/31/2022] [Indexed: 11/16/2022] Open
Abstract
Antimicrobial resistance is one of the major human health threats, with significant impacts on the global economy. Antibiotics are becoming increasingly ineffective as drug-resistance spreads, imposing an urgent need for new and innovative antimicrobial agents. Metal complexes are an untapped source of antimicrobial potential. Rhenium complexes, amongst others, are particularly attractive due to their low in vivo toxicity and high antimicrobial activity, but little is known about their targets and mechanism of action. In this study, a series of rhenium di- and tricarbonyl diimine complexes were prepared and evaluated for their antimicrobial potential against eight different microorganisms comprising Gram-negative and -positive bacteria. Our data showed that none of the Re dicarbonyl or neutral tricarbonyl species have either bactericidal or bacteriostatic potential. In order to identify possible targets of the molecules, and thus possibly understand the observed differences in the antimicrobial efficacy of the molecules, we computationally evaluated the binding affinity of active and inactive complexes against structurally characterized membrane-bound S. aureus proteins. The computational analysis indicates two possible major targets for this class of compounds, namely lipoteichoic acids flippase (LtaA) and lipoprotein signal peptidase II (LspA). Our results, consistent with the published in vitro studies, will be useful for the future design of rhenium tricarbonyl diimine-based antibiotics.
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Lever J, Kreuder F, Henry J, Hung A, Allard PM, Brkljača R, Rix C, Taki AC, Gasser RB, Kaslin J, Wlodkowic D, Wolfender JL, Urban S. Targeted Isolation of Antibiotic Brominated Alkaloids from the Marine Sponge Pseudoceratina durissima Using Virtual Screening and Molecular Networking. Mar Drugs 2022; 20:md20090554. [PMID: 36135743 PMCID: PMC9503778 DOI: 10.3390/md20090554] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/22/2022] [Accepted: 08/25/2022] [Indexed: 11/23/2022] Open
Abstract
Many targeted natural product isolation approaches rely on the use of pre-existing bioactivity information to inform the strategy used for the isolation of new bioactive compounds. Bioactivity information can be available either in the form of prior assay data or via Structure Activity Relationship (SAR) information which can indicate a potential chemotype that exhibits a desired bioactivity. The work described herein utilizes a unique method of targeted isolation using structure-based virtual screening to identify potential antibacterial compounds active against MRSA within the marine sponge order Verongiida. This is coupled with molecular networking-guided, targeted isolation to provide a novel drug discovery procedure. A total of 12 previously reported bromotyrosine-derived alkaloids were isolated from the marine sponge species Pseudoceratina durissima, and the compound, (+)-aeroplysinin-1 (1) displayed activity against the MRSA pathogen (MIC: <32 µg/mL). The compounds (1−3, 6 and 9) were assessed for their central nervous system (CNS) interaction and behavioral toxicity to zebrafish (Danio rerio) larvae, whereby several of the compounds were shown to induce significant hyperactivity. Anthelmintic activity against the parasitic nematode Haemonchus contorutus was also evaluated (2−4, 6−8).
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Affiliation(s)
- James Lever
- School of Science (Applied Chemistry and Environmental Sciences), RMIT University, GPO Box 2476 Melbourne, VIC 3001, Australia
| | - Florian Kreuder
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Jason Henry
- Neurotoxicology Lab., School of Science (Biosciences), RMIT University, Bundoora, VIC 3083, Australia
| | - Andrew Hung
- School of Science (Applied Chemistry and Environmental Sciences), RMIT University, GPO Box 2476 Melbourne, VIC 3001, Australia
| | | | - Robert Brkljača
- Monash Biomedical Imaging, Monash University, Clayton, VIC 3168, Australia
| | - Colin Rix
- School of Science (Applied Chemistry and Environmental Sciences), RMIT University, GPO Box 2476 Melbourne, VIC 3001, Australia
| | - Aya C. Taki
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Veterinary and Agriculture Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Robin B. Gasser
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Veterinary and Agriculture Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Jan Kaslin
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Donald Wlodkowic
- Neurotoxicology Lab., School of Science (Biosciences), RMIT University, Bundoora, VIC 3083, Australia
| | - Jean-Luc Wolfender
- School of Pharmaceutical Sciences of Western Switzerland, University of Geneva, CMU, Rue Michel-Servet 1, 1211 Geneva, Switzerland
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, CMU, 1211 Geneva, Switzerland
| | - Sylvia Urban
- School of Science (Applied Chemistry and Environmental Sciences), RMIT University, GPO Box 2476 Melbourne, VIC 3001, Australia
- Correspondence:
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Kaushik S, He H, Dalbey RE. Bacterial Signal Peptides- Navigating the Journey of Proteins. Front Physiol 2022; 13:933153. [PMID: 35957980 PMCID: PMC9360617 DOI: 10.3389/fphys.2022.933153] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 06/21/2022] [Indexed: 11/18/2022] Open
Abstract
In 1971, Blobel proposed the first statement of the Signal Hypothesis which suggested that proteins have amino-terminal sequences that dictate their export and localization in the cell. A cytosolic binding factor was predicted, and later the protein conducting channel was discovered that was proposed in 1975 to align with the large ribosomal tunnel. The 1975 Signal Hypothesis also predicted that proteins targeted to different intracellular membranes would possess distinct signals and integral membrane proteins contained uncleaved signal sequences which initiate translocation of the polypeptide chain. This review summarizes the central role that the signal peptides play as address codes for proteins, their decisive role as targeting factors for delivery to the membrane and their function to activate the translocation machinery for export and membrane protein insertion. After shedding light on the navigation of proteins, the importance of removal of signal peptide and their degradation are addressed. Furthermore, the emerging work on signal peptidases as novel targets for antibiotic development is described.
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Liaci AM, Steigenberger B, Telles de Souza PC, Tamara S, Gröllers-Mulderij M, Ogrissek P, Marrink SJ, Scheltema RA, Förster F. Structure of the human signal peptidase complex reveals the determinants for signal peptide cleavage. Mol Cell 2021; 81:3934-3948.e11. [PMID: 34388369 DOI: 10.1016/j.molcel.2021.07.031] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 06/02/2021] [Accepted: 07/26/2021] [Indexed: 12/18/2022]
Abstract
The signal peptidase complex (SPC) is an essential membrane complex in the endoplasmic reticulum (ER), where it removes signal peptides (SPs) from a large variety of secretory pre-proteins with exquisite specificity. Although the determinants of this process have been established empirically, the molecular details of SP recognition and removal remain elusive. Here, we show that the human SPC exists in two functional paralogs with distinct proteolytic subunits. We determined the atomic structures of both paralogs using electron cryo-microscopy and structural proteomics. The active site is formed by a catalytic triad and abuts the ER membrane, where a transmembrane window collectively formed by all subunits locally thins the bilayer. Molecular dynamics simulations indicate that this unique architecture generates specificity for SPs based on the length of their hydrophobic segments.
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Affiliation(s)
- A Manuel Liaci
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, the Netherlands
| | - Barbara Steigenberger
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Paulo Cesar Telles de Souza
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, the Netherlands; Molecular Microbiology and Structural Biochemistry, UMR 5086, CNRS and University of Lyon, Lyon, France
| | - Sem Tamara
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Mariska Gröllers-Mulderij
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, the Netherlands
| | - Patrick Ogrissek
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, the Netherlands; Institute of Chemistry and Metabolomics, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, the Netherlands
| | - Richard A Scheltema
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Friedrich Förster
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, the Netherlands.
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Upert G, Luther A, Obrecht D, Ermert P. Emerging peptide antibiotics with therapeutic potential. MEDICINE IN DRUG DISCOVERY 2021; 9:100078. [PMID: 33398258 PMCID: PMC7773004 DOI: 10.1016/j.medidd.2020.100078] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/15/2020] [Accepted: 12/27/2020] [Indexed: 02/09/2023] Open
Abstract
This review covers some of the recent progress in the field of peptide antibiotics with a focus on compounds with novel or established mode of action and with demonstrated efficacy in animal infection models. Novel drug discovery approaches, linear and macrocyclic peptide antibiotics, lipopeptides like the polymyxins as well as peptides addressing targets located in the plasma membrane or in the outer membrane of bacterial cells are discussed.
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Key Words
- ADMET, absorption, distribution, metabolism and excretion – toxicity in pharmacokinetics
- AMP, antimicrobial peptide
- AMR, antimicrobial resistance
- ATCC, ATCC cell collection
- Antibiotic
- BAM, β-barrel assembly machinery
- CC50, cytotoxic concentration to kill 50% of cells
- CD, circular dichroism
- CFU, colony forming unit
- CLSI, clinical and laboratory standards institute
- CMS, colistin methane sulfonate
- DMPC, 1,2-dimyristoyl-sn-glycero-3-phosphocholine
- ESKAPE, acronym encompassing six bacterial pathogens (often carrying antibiotic resistance): Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumonia, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp
- FDA, U. S. Food and Drug Administration
- HABP, hospital acquired bacterial pneumonia
- HDP, host-defense peptide
- HEK293, human embryonic kidney 293 cells
- HK-2, human kidney 2 cells (proximal tubular cell line)
- HepG2, human hepatocellular carcinoma cell line
- Hpg, 4-hydroxy-phenyl glycine
- ITC, isothermal titration calorimetry
- KPC, Klebsiella pneumoniae metallo-β-lactamase C resistant
- LPS, lipopolysaccharide
- LptA, lipopolysaccharide transport protein A
- LptC, lipopolysaccharide transport protein C
- LptD, lipopolysaccharide transport protein D
- MDR, multidrug-resistant
- MH-I, Müller-Hinton broth I
- MH-II, Müller-Hinton broth II (cation adjusted)
- MIC, minimal inhibitory concentration
- MRSA, methicilline-resistant S. aureus
- MSSA, methicilline-sensitive S. aureus
- MoA, mechanism (mode) of action
- NDM-1, New Delhi metallo-β-lactamase resistant
- NOAEL, no adverse effect level
- ODL, odilorhabdin
- OMPTA (outer membrane targeting antibiotic)
- OMPTA, outer membrane targeting antibiotic
- Omp, outer membrane protein
- PBMC, peripheral mononuclear blood cell
- PBP, penicillin-binding protein
- PBS, phosphate-buffered saline
- PK, pharmacokinetics
- POPC, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine
- POPG, 2-oleoyl-1-palmitoyl-sn-glycero-3-phospho-(1-glycerol)
- PrAMPs, polyproline antimicrobial peptides
- RBC, red blood cell
- SAR, structure-activity relationship
- SPR, surface plasmon resonance
- SPase I, signal peptidase I
- VABP, ventilator associated bacterial pneumonia
- VIM-1, beta-lactamase 2 (K. pneumoniae)
- VISA, vancomycin-intermediate S. aureus
- VRE, vancomycin-resistant enterococcus
- WHO, World Health Organization
- WT, wild type
- WTA, wall teichoic acid
- XDR, extremely drug-resistant
- antimicrobial peptide
- antimicrobial resistance
- bid, bis in die (two times a day)
- i.p., intraperitoneal
- i.v., intravenous
- lipopeptide
- mITT population, minimal intend-to-treat population
- peptide antibiotic
- s.c., subcutaneous
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Affiliation(s)
- Gregory Upert
- Polyphor Ltd, Hegenheimermattweg 125, 4123 Allschwil, Switzerland
| | - Anatol Luther
- Bachem AG, Hauptstrasse 114, 4416 Bubendorf, Switzerland
| | - Daniel Obrecht
- Polyphor Ltd, Hegenheimermattweg 125, 4123 Allschwil, Switzerland
| | - Philipp Ermert
- Polyphor Ltd, Hegenheimermattweg 125, 4123 Allschwil, Switzerland
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Monteiro AFM, Scotti MT, Speck-Planche A, Barros RPC, Scotti L. In Silico Studies for Bacterystic Evaluation against Staphylococcus aureus of 2-Naphthoic Acid Analogues. Curr Top Med Chem 2020; 20:293-304. [DOI: 10.2174/1568026619666191206111742] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 09/01/2019] [Accepted: 09/10/2019] [Indexed: 01/27/2023]
Abstract
Background:
Staphylococcus aureus is a gram-positive spherical bacterium commonly present in
nasal fossae and in the skin of healthy people; however, in high quantities, it can lead to complications that
compromise health. The pathologies involved include simple infections, such as folliculitis, acne, and delay in
the process of wound healing, as well as serious infections in the CNS, meninges, lung, heart, and other areas.
Aim:
This research aims to propose a series of molecules derived from 2-naphthoic acid as a bioactive in the
fight against S. aureus bacteria through in silico studies using molecular modeling tools.
Methods:
A virtual screening of analogues was done in consideration of the results that showed activity according
to the prediction model performed in the KNIME Analytics Platform 3.6, violations of the Lipinski
rule, absorption rate, cytotoxicity risks, energy of binder-receptor interaction through molecular docking, and
the stability of the best profile ligands in the active site of the proteins used (PDB ID 4DXD and 4WVG).
Results:
Seven of the 48 analogues analyzed showed promising results for bactericidal action against S.
aureus.
Conclusion:
It is possible to conclude that ten of the 48 compounds derived from 2-naphthoic acid presented
activity based on the prediction model generated, of which seven presented no toxicity and up to one violation
to the Lipinski rule.
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Affiliation(s)
| | - Marcus Tullius Scotti
- Federal University of Paraíba, Health Science Center, 50670-910, Joao Pessoa, PB, Brazil
| | - Alejandro Speck-Planche
- Department of Chemistry, Institute of Pharmacy, I.M. Sechenov First Moscow State Medical University, Trubetskaya Str., 8, b. 2, 119992, Moscow, Russian Federation
| | | | - Luciana Scotti
- Federal University of Paraíba, Health Science Center, 50670-910, Joao Pessoa, PB, Brazil
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Group A Streptococcus T Antigens Have a Highly Conserved Structure Concealed under a Heterogeneous Surface That Has Implications for Vaccine Design. Infect Immun 2019; 87:IAI.00205-19. [PMID: 30936156 DOI: 10.1128/iai.00205-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 03/25/2019] [Indexed: 12/20/2022] Open
Abstract
Group A Streptococcus (GAS) (Streptococcus pyogenes) is an important human pathogen associated with significant global morbidity and mortality for which there is no safe and efficacious vaccine. The T antigen, a protein that polymerizes to form the backbone of the GAS pilus structure, is a potential vaccine candidate. Previous surveys of the tee gene, which encodes the T antigen, have identified 21 different tee types and subtypes such that any T antigen-based vaccine must be multivalent and carefully designed to provide broad strain coverage. In this study, the crystal structures of three two-domain T antigens (T3.2, T13, and T18.1) were determined and found to have remarkable structural similarity to the previously reported T1 antigen, despite moderate overall sequence similarity. This has enabled reliable modeling of all major two-domain T antigens to reveal that T antigen sequence variation is distributed along the full length of the protein and shields a highly conserved core. Immunoassays performed with sera from immunized animals and commercial T-typing sera identified a significant cross-reactive antibody response between T18.1, T18.2, T3.2, and T13. The existence of shared epitopes between T antigens, combined with the remarkably conserved structure and high level of surface sequence divergence, has important implications for the design of multivalent T antigen-based vaccines.
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Abstract
Signal peptidases are the membrane bound enzymes that cleave off the amino-terminal signal peptide from secretory preproteins . There are two types of bacterial signal peptidases . Type I signal peptidase utilizes a serine/lysine catalytic dyad mechanism and is the major signal peptidase in most bacteria. Type II signal peptidase is an aspartic protease specific for prolipoproteins. This chapter will review what is known about the structure, function and mechanism of these unique enzymes.
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Affiliation(s)
- Mark Paetzel
- Department of Molecular Biology and Biochemistry, Simon Fraser University, South Science Building 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
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11
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A comprehensive review of signal peptides: Structure, roles, and applications. Eur J Cell Biol 2018; 97:422-441. [DOI: 10.1016/j.ejcb.2018.06.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 06/18/2018] [Accepted: 06/18/2018] [Indexed: 01/06/2023] Open
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Giegé R. What macromolecular crystallogenesis tells us - what is needed in the future. IUCRJ 2017; 4:340-349. [PMID: 28875021 PMCID: PMC5571797 DOI: 10.1107/s2052252517006595] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 05/02/2017] [Indexed: 05/05/2023]
Abstract
Crystallogenesis is a longstanding topic that has transformed into a discipline that is mainly focused on the preparation of crystals for practising crystallo-graphers. Although the idiosyncratic features of proteins have to be taken into account, the crystallization of proteins is governed by the same physics as the crystallization of inorganic materials. At present, a diversified panel of crystallization methods adapted to proteins has been validated, and although only a few methods are in current practice, the success rate of crystallization has increased constantly, leading to the determination of ∼105 X-ray structures. These structures reveal a huge repertoire of protein folds, but they only cover a restricted part of macromolecular diversity across the tree of life. In the future, crystals representative of missing structures or that will better document the structural dynamics and functional steps underlying biological processes need to be grown. For the pertinent choice of biologically relevant targets, computer-guided analysis of structural databases is needed. From another perspective, crystallization is a self-assembly process that can occur in the bulk of crowded fluids, with crystals being supramolecular assemblies. Life also uses self-assembly and supramolecular processes leading to transient, or less often stable, complexes. An integrated view of supramolecularity implies that proteins crystallizing either in vitro or in vivo or participating in cellular processes share common attributes, notably determinants and antideterminants that favour or disfavour their correct or incorrect associations. As a result, under in vivo conditions proteins show a balance between features that favour or disfavour association. If this balance is broken, disorders/diseases occur. Understanding crystallization under in vivo conditions is a challenge for the future. In this quest, the analysis of packing contacts and contacts within oligomers will be crucial in order to decipher the rules governing protein self-assembly and will guide the engineering of novel biomaterials. In a wider perspective, understanding such contacts will open the route towards supramolecular biology and generalized crystallogenesis.
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Affiliation(s)
- Richard Giegé
- Architecture et Réactivité de l’ARN, UPR 9002, Université de Strasbourg and CNRS, F-67084 Strasbourg, France
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13
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14
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Abstract
Signal peptidases are membrane proteases that play crucial roles in the protein transport pathway of bacteria. They cleave off the signal peptide from precursor proteins that are membrane inserted by the SecYEG or Tat translocons. Signal peptide cleavage releases the translocated protein from the inner membrane allowing the protein to be exported to the periplasm, outer membrane, or secreted into the medium. Signal peptidases are very important proteins to study. They are unique serine proteases with a Ser-Lys dyad, catalyze cleavage at the membrane surface, and are promising potential antibacterial drug targets. This chapter will focus on the isolation of signal peptidases and the preprotein substrates, as well as describe a peptide library approach for characterizing the substrate specificity.
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Affiliation(s)
- R E Dalbey
- The Ohio State University, Columbus, OH, United States.
| | - D Pei
- The Ohio State University, Columbus, OH, United States
| | - Ö D Ekici
- The Ohio State University, Newark, OH, United States
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