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Hernández-Cid A, Lozano-Aponte J, Scior T. Molecular Dynamics and Docking Simulations of Homologous RsmE Methyltransferases Hints at a General Mechanism for Substrate Release upon Uridine Methylation on 16S rRNA. Int J Mol Sci 2023; 24:16722. [PMID: 38069045 PMCID: PMC10706118 DOI: 10.3390/ijms242316722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 11/12/2023] [Accepted: 11/14/2023] [Indexed: 12/18/2023] Open
Abstract
In this study, molecular dynamics (MD) and docking simulations were carried out on the crystal structure of Neisseria Gonorrhoeae RsmE aiming at free energy of binding estimation (ΔGbinding) of the methyl transfer substrate S-adenosylmethionine (SAM), as well as its homocysteine precursor S-adenosylhomocysteine (SAH). The mechanistic insight gained was generalized in view of existing homology to two other crystal structures of RsmE from Escherichia coli and Aquifex aeolicus. As a proof of concept, the crystal poses of SAM and SAH were reproduced reflecting a more general pattern of molecular interaction for bacterial RsmEs. Our results suggest that a distinct set of conserved residues on loop segments between β12, α6, and Met169 are interacting with SAM and SAH across these bacterial methyltransferases. Comparing molecular movements over time (MD trajectories) between Neisseria gonorrhoeae RsmE alone or in the presence of SAH revealed a hitherto unknown gatekeeper mechanism by two isoleucine residues, Ile171 and Ile219. The proposed gating allows switching from an open to a closed state, mimicking a double latch lock. Additionally, two key residues, Arg221 and Thr222, were identified to assist the exit mechanism of SAH, which could not be observed in the crystal structures. To the best of our knowledge, this study describes for the first time a general catalytic mechanism of bacterial RsmE on theoretical ground.
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Affiliation(s)
- Aaron Hernández-Cid
- Biochemistry Department, BioPlaster Research Institute, Puebla C.P. 72260, Mexico;
| | - Jorge Lozano-Aponte
- Escuela de Ingeniería y Ciencia, Instituto Tecnológico y de Estudios Superiores de Monterrey, Campus Puebla, Puebla C.P. 72453, Mexico;
| | - Thomas Scior
- Departmento de Farmacia, Facultad de Ciencias Químicas, Ciudad Univeristaria, Benemérita Universidad Autónoma de Puebla, Puebla C.P. 72570, Mexico
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Guirgis SA, El-Halfawy KA, Alalem M, Khalil H. Legionellapneumophila induces methylomic changes in ten-eleven translocation to ensure bacterial reproduction in human lung epithelial cells. J Med Microbiol 2023; 72. [PMID: 36927577 DOI: 10.1099/jmm.0.001676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
Abstract
Introduction. Legionella pneumophila is a Gram-negative flagellated bacteria that can infect human lungs and cause a severe form of pneumonia named Legionnaires' disease.Hypothesis. We hypothesize that L. pneumophila infection induces methylomic changes in methylcytosine dioxygenases, ten-eleven translocation (TET) genes, and controls DNA methylation following infection.Aim. In the current research, we sought to further investigate DNA methylation changes in human lung epithelial cells upon L. pneumophila infection and determine how methylation inhibitor agents disturb L. pneumophila reproduction.Methodology. A549 cell line was used in L. pneumophila infection and inhibitors' treatment, including 5-azacytidine (5-AZA) and (-)-epigallocatechin-3-O-gallate (EGCG).Results. Interestingly, DNA methylation analysis of infected A549 using sodium bisulfite PCR and the methylation-sensitive HpaII enzyme showed potential methylation activity within the promoter regions of ten-eleven translocation (TET) genes located on CpG/397-8 and CpG/385-6 of TET1 and TET3, respectively. Such methylation changes in TET effectors decreased their expression profile following infection, indicated by quantitative real-time PCR (RT-qPCR), immunoblotting and flow cytometry. Furthermore, pre-treatment of A549 cells with 5-AZA or EGCG significantly decreased the bacterial reproduction characterized by the expression of L. pneumophila 16S ribosomal RNA and the c.f.u. ml-1 of bacterial particles. Moreover, both methylation inhibitors showed potent inhibition of methionine synthase (MS) expression, which was further confirmed by the docking analysis of inhibitor ligands and crystal structure of MS protein.Conclusion. These data provide evidence for the methylomic changes in the promoter region of TET1 and TET3 by L. pneumophila infection in the A549 cell line and suggest the anti-bacterial properties of 5-AZA and EGCG, as methylation inhibitors, are due to targeting the epigenetic effector methionine synthase.
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Affiliation(s)
- Sherry A Guirgis
- Department of Molecular Biology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat, Egypt
| | - Khalil A El-Halfawy
- Department of Molecular Biology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat, Egypt
| | - Mai Alalem
- Department of Molecular Biology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat, Egypt
| | - Hany Khalil
- Department of Molecular Biology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat, Egypt
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Thomas DR, Newton P, Lau N, Newton HJ. Interfering with Autophagy: The Opposing Strategies Deployed by Legionella pneumophila and Coxiella burnetii Effector Proteins. Front Cell Infect Microbiol 2020; 10:599762. [PMID: 33251162 PMCID: PMC7676224 DOI: 10.3389/fcimb.2020.599762] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/13/2020] [Indexed: 12/14/2022] Open
Abstract
Autophagy is a fundamental and highly conserved eukaryotic process, responsible for maintaining cellular homeostasis and releasing nutrients during times of starvation. An increasingly important function of autophagy is its role in the cell autonomous immune response; a process known as xenophagy. Intracellular pathogens are engulfed by autophagosomes and targeted to lysosomes to eliminate the threat to the host cell. To counteract this, many intracellular bacterial pathogens have developed unique approaches to overcome, evade, or co-opt host autophagy to facilitate a successful infection. The intracellular bacteria Legionella pneumophila and Coxiella burnetii are able to avoid destruction by the cell, causing Legionnaires' disease and Q fever, respectively. Despite being related and employing homologous Dot/Icm type 4 secretion systems (T4SS) to translocate effector proteins into the host cell, these pathogens have developed their own unique intracellular niches. L. pneumophila evades the host endocytic pathway and instead forms an ER-derived vacuole, while C. burnetii requires delivery to mature, acidified endosomes which it remodels into a large, replicative vacuole. Throughout infection, L. pneumophila effectors act at multiple points to inhibit recognition by xenophagy receptors and disrupt host autophagy, ensuring it avoids fusion with destructive lysosomes. In contrast, C. burnetii employs its effector cohort to control autophagy, hypothesized to facilitate the delivery of nutrients and membrane to support the growing vacuole and replicating bacteria. In this review we explore the effector proteins that these two organisms utilize to modulate the host autophagy pathway in order to survive and replicate. By better understanding how these pathogens manipulate this highly conserved pathway, we can not only develop better treatments for these important human diseases, but also better understand and control autophagy in the context of human health and disease.
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Affiliation(s)
| | | | | | - Hayley J. Newton
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
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Restriction of S-adenosylmethionine conformational freedom by knotted protein binding sites. PLoS Comput Biol 2020; 16:e1007904. [PMID: 32453784 PMCID: PMC7319350 DOI: 10.1371/journal.pcbi.1007904] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 06/26/2020] [Accepted: 04/23/2020] [Indexed: 02/07/2023] Open
Abstract
S-adenosylmethionine (SAM) is one of the most important enzyme substrates. It is vital for the function of various proteins, including large group of methyltransferases (MTs). Intriguingly, some bacterial and eukaryotic MTs, while catalysing the same reaction, possess significantly different topologies, with the former being a knotted one. Here, we conducted a comprehensive analysis of SAM conformational space and factors that affect its vastness. We investigated SAM in two forms: free in water (via NMR studies and explicit solvent simulations) and bound to proteins (based on all data available in the PDB and on all-atom molecular dynamics simulations in water). We identified structural descriptors—angles which show the major differences in SAM conformation between unknotted and knotted methyltransferases. Moreover, we report that this is caused mainly by a characteristic for knotted MTs compact binding site formed by the knot and the presence of adenine-binding loop. Additionally, we elucidate conformational restrictions imposed on SAM molecules by other protein groups in comparison to conformational space in water. The topology of a folded polypeptide chain has great impact on the resulting protein function and its interaction with ligands. Interestingly, topological constraints appear to affect binding of one of the most ubiquitous substrates in the cell, S-adenosylmethionine (SAM), to its target proteins. Here, we demonstrate how binding sites of specific proteins restrict SAM conformational freedom in comparison to its unbound state, with a special interest in proteins with non-trivial topology, including an exciting group of knotted methyltransferases. Using a vast array of computational methods combined with NMR experiments, we identify key structural features of knotted methyltransferases that impose unorthodox SAM conformations. We compare them with the characteristics of standard, unknotted SAM binding proteins. These results are significant for understanding differences between analogous, yet topologically different enzymes, as well as for future rational drug design.
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Abd El Maksoud AI, Elebeedy D, Abass NH, Awad AM, Nasr GM, Roshdy T, Khalil H. Methylomic Changes of Autophagy-Related Genes by Legionella Effector Lpg2936 in Infected Macrophages. Front Cell Dev Biol 2020; 7:390. [PMID: 32064256 PMCID: PMC6999459 DOI: 10.3389/fcell.2019.00390] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/23/2019] [Indexed: 12/26/2022] Open
Abstract
Legionella pneumophila (L. pneumophila) is a Gram-negative bacterium that infects the human respiratory tract causing Legionnaires' disease, a severe form of pneumonia. Recently, rising evidence indicated the ability of Legionella to regulate host defense via its type 4 secretion system including hundreds of effectors that promote intracellular bacterial replication. The host defense against such invaders includes autophagic machinery that is responsible for degradation events of invading pathogens and recycling of cell components. The interplay between host autophagy and Legionella infection has been reported, indicating the role of bacterial effectors in the regulation of autophagy during intracellular replication. Here, we investigated the potential impact of Legionella effector Lpg2936 in the regulation of host autophagy and its role in bacterial replication using mice-derived macrophages and human lung epithelial cells (A549 cells). First, monitoring of autophagic flux following infection revealed a marked reduction of Atg7 and LC3B expression profile and low accumulation levels of autophagy-related LC3-I, LC3-II, and the Atg12-Atg5 protein complex. A novel methyladenine alteration was observed due to irreversible changes of GATC motif to G(6 mA) TC in the promoter region of Atg7 and LC3B indicated by cleaved genomic-DNA using the N6 methyladenine-sensitive restriction enzyme DpnI. Interestingly, RNA interference (RNAi) of Lpg2936 in infected macrophages showed dramatic inhibition of bacterial replication by restoring the expression of autophagy-related proteins. This is accompanied by low production levels of bacterial-associated pro-inflammatory cytokines. Furthermore, a constructed Lpg2936 segment in the GFP expression vector was translocated in the host nucleus and successfully induced methyladenine changes in Atg7 and LC3B promoter region and subsequently regulated autophagy in A549 cells independent of infection. Finally, treatment with methylation inhibitors 5-AZA and (2)-Epigallocatechin-3-gallate (EGCG) was able to restore autophagy-related gene expression and to disrupt bacterial replication in infected macrophages. This cumulative evidence indicates the methylation effect of Legionella effector Lpg2936 on the host autophagy-related molecules Atg7 and LC3B and subsequent reduction in the expression levels of autophagy effectors during intracellular replication of L. pneumophila.
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Affiliation(s)
- Ahmed I. Abd El Maksoud
- Industrial Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat City, Egypt
| | - Dalia Elebeedy
- College of Biotechnology, Misr University for Science and Technology (MUST), 6th of October City, Egypt
| | - Nasser H. Abass
- Department of Molecular Biology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat City, Egypt
| | - Ahmed M. Awad
- Department of Molecular Biology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat City, Egypt
| | - Ghada M. Nasr
- Molecular Diagnostics Department, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat City, Egypt
| | - Tamer Roshdy
- Department of Molecular Biology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat City, Egypt
| | - Hany Khalil
- Department of Molecular Biology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat City, Egypt
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Nanev CN, Saridakis E, Govada L, Kassen SC, Solomon HV, Chayen NE. Hydrophobic Interface-Assisted Protein Crystallization: Theory and Experiment. ACS APPLIED MATERIALS & INTERFACES 2019; 11:12931-12940. [PMID: 30860355 DOI: 10.1021/acsami.8b20995] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Macromolecular crystallization is crucial to a large number of scientific fields, including structural biology; drug design, formulation, and delivery; manufacture of biomaterials; and preparation of foodstuffs. The purpose of this study is to facilitate control of crystallization, by investigating hydrophobic interface-assisted protein crystallization both theoretically and experimentally. The application of hydrophobic liquids as nucleation promoters or suppressors has rarely been investigated, and provides an underused avenue to explore in protein crystallization. Theoretically, crystal nucleation is regarded as a two-step process, the first step being a local increase in protein concentration due to its adsorption on the hydrophobic surface. Subsequently, the protein is ordered in a crystal lattice. The energetic aspect of crystal nucleation on water/hydrophobic substance interfaces is approached by calculating the balance between the cohesive energy maintaining integrity of the two-dimensional crystal nucleus and the sum of destructive energies tending to tear up the crystal. This is achieved by comparing the number of bonds shared by the units forming the crystal and the number of unshared (dangling) bonds on the crystal surface pointing toward the solution. The same approach is extended to three-dimensional protein crystal nucleation at water/hydrophobic liquid interfaces. Experimentally, we studied protein crystallization over oils and other hydrophobic liquids (paraffin oil, FC-70 Fluorinert fluorinated oil, and three chlorinated hydrocarbons). Crystallizations of α-lactalbumin and lysozyme are compared, and additional information is acquired by studying α-crustacyanin, trypsin, an insulin analogue, and protein Lpg2936. Depending on the protein type, concentration, and the interface aging time, the proteins exhibit different crystallization propensities depending on the hydrophobic liquid used. Some hydrophobic liquids provoke an increase in the effective supersaturation, which translates to enhancement of crystal nucleation at their interface with the crystallization solution, leading to the formation of crystals.
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Affiliation(s)
- Christo N Nanev
- Rostislaw Kaischew Institute of Physical Chemistry , Bulgarian Academy of Sciences , Acad. G. Bonchev Str. Bl. 11 , Sofia 1113 , Bulgaria
| | - Emmanuel Saridakis
- Structural and Supramolecular Chemistry Laboratory, Institute of Nanoscience and Nanotechnology , National Centre for Scientific Research "Demokritos" , Athens 15310 , Greece
| | - Lata Govada
- Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine , Imperial College London , London SW7 2AZ , U.K
| | - Sean C Kassen
- Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine , Imperial College London , London SW7 2AZ , U.K
| | - Hodaya V Solomon
- Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine , Imperial College London , London SW7 2AZ , U.K
| | - Naomi E Chayen
- Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine , Imperial College London , London SW7 2AZ , U.K
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