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Zhao X, Ma X, Dupius JH, Qi R, Tian JJ, Chen J, Ou X, Qian Z, Liang D, Wang P, Yada RY, Wang S. Negatively charged phospholipids accelerate the membrane fusion activity of the plant-specific insert domain of an aspartic protease. J Biol Chem 2021; 298:101430. [PMID: 34801553 PMCID: PMC8683733 DOI: 10.1016/j.jbc.2021.101430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 11/10/2021] [Accepted: 11/16/2021] [Indexed: 11/27/2022] Open
Abstract
Various plants use antimicrobial proteins/peptides to resist phytopathogens. In the potato, Solanum tuberosum, the plant-specific insert (PSI) domain of an aspartic protease performs this role by disrupting phytopathogen plasma membranes. However, the mechanism by which PSI selects target membranes has not been elucidated. Here, we studied PSI-induced membrane fusion, focusing on the effects of lipid composition on fusion efficiency. Membrane fusion by the PSI involves an intermediate state whereby adjacent liposomes share their bilayers. We found that increasing the concentration of negatively charged phosphatidylserine (PS) phospholipids substantially accelerated PSI-mediated membrane fusion. NMR data demonstrated that PS did not affect the binding between the PSI and liposomes but had seminal effects on the dynamics of PSI interaction with liposomes. In PS-free liposomes, the PSI underwent significant motion, which was suppressed on PS-contained liposomes. Molecular dynamics simulations showed that the PSI binds to PS-containing membranes with a dominant angle ranging from −31° to 30°, with respect to the bilayer, and is closer to the membrane surfaces. In contrast, PSI is mobile and exhibits multiple topological states on the surface of PS-free membranes. Taken together, our data suggested that PS lipids limit the motion of the anchored PSI, bringing it closer to the membrane surface and efficiently bridging different liposomes to accelerate fusion. As most phytopathogens have a higher content of negatively charged lipids as compared with host cells, these results indicate that the PSI selectively targets negatively charged lipids, which likely represents a way of distinguishing the pathogen from the host.
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Affiliation(s)
- Xiaoli Zhao
- College of Chemistry and Molecular Engineering and Beijing NMR Center, Peking University, Beijing, China; State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China; Beijing National Laboratory for Molecular Sciences, Beijing, China
| | - Xiaomin Ma
- Cryo-EM Center, Southern University of Science and Technology, Shenzhen, China
| | - John H Dupius
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ruxi Qi
- Cryo-EM Center, Southern University of Science and Technology, Shenzhen, China
| | - Jenny Jingxin Tian
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jiaxin Chen
- College of Chemistry and Molecular Engineering and Beijing NMR Center, Peking University, Beijing, China
| | - Xiuyuan Ou
- MOH Key Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Science, Beijing, China
| | - Zhaohui Qian
- MOH Key Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Science, Beijing, China
| | - Dehai Liang
- College of Chemistry and Molecular Engineering and Beijing NMR Center, Peking University, Beijing, China
| | - Peiyi Wang
- Cryo-EM Center, Southern University of Science and Technology, Shenzhen, China.
| | - Rickey Y Yada
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Shenlin Wang
- College of Chemistry and Molecular Engineering and Beijing NMR Center, Peking University, Beijing, China; State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China; Beijing National Laboratory for Molecular Sciences, Beijing, China.
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Czubinski J, Dwiecki K. Heat-induced changes in lupin seed γ-conglutin structure promote its interaction with model phospholipid membranes. Food Chem 2021; 374:131533. [PMID: 34862076 DOI: 10.1016/j.foodchem.2021.131533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 11/16/2022]
Abstract
A number of scientific data indicate that γ-conglutin can be internalised by different human cells and undergoes secretion from the seed in response to high temperature. In both of these cases, the protein must interact in some manner with biological membranes, however, the mechanisms underlying this phenomenon remain unknown. Herein, we found that the remarkable change of total surface hydrophobicity after appropriate heat treatment of γ-conglutin monomer led to its interaction with model membranes (liposomes). Before the interaction, the protein undergoes an intriguing thermal unfolding pattern which was studied based on a spectroscopic approach. Insight into the interaction mechanism with liposomes was possible thanks to applying two molecular probes that were differentially localised in the lipid bilayer. The results show that the thermal rearranged γ-coglutin monomer affects hydrocarbon chains in model membranes leading to their morphology change and disruption. The main driving force of this phenomenon is based on hydrophobic interaction.
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Affiliation(s)
- Jaroslaw Czubinski
- Department of Food Biochemistry and Analysis, Poznan University of Life Sciences, Wojska Polskiego 28, 60-637 Poznan, Poland.
| | - Krzysztof Dwiecki
- Department of Food Biochemistry and Analysis, Poznan University of Life Sciences, Wojska Polskiego 28, 60-637 Poznan, Poland
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Ibañez IL, Muñoz FF, Zoppi J, Abaurrea RA, Scandogliero EA, Durán H, Guevara MG. In vivo tumor growth inhibition by Solanum tuberosum aspartic protease 3 (StAP3) treatment. Bioorg Med Chem Lett 2021; 41:127959. [PMID: 33766772 DOI: 10.1016/j.bmcl.2021.127959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/26/2021] [Accepted: 03/05/2021] [Indexed: 11/17/2022]
Abstract
Solanum tuberosum aspartic Proteases (StAPs) show selective plasma membrane permeabilization, inducing cytotoxicity of cancer cells versus normal cells in vitro. Herein, we aimed to evaluate both StAP3 systemic toxicity and antitumoral activity against human melanoma in vivo. The toxicity of a single high dose of StAP3 (10 µg/g body weight, intraperitoneally) was assessed in a Balb/c mice model. Subcutaneous A375 human melanoma xenografts in athymic nude (nu/nu) mice were induced. Once tumors developed (mean larger dimension = 3.8 ± 0.09 mm), mice were StAP3-treated (6 µg/g body weight, subcutaneously under the tumor at a single dose). For both models, controls were treated with physiologic saline solution. StAP3-treated mice showed a significant inhibition of tumor growth (p < 0.05) compared with controls. No signs of toxicity were detected in StAP3-treated mice in both models. These results suggest the potential of these plant proteases as anticancer agents.
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Affiliation(s)
- Irene L Ibañez
- Institute of Nanoscience and Nanotechnology (INN), National Atomic Energy Commission (CNEA), National Scientific and Technical Research Council (CONICET), Constituyentes Node, Av. General Paz 1499, (B1650KNA) San Martín, Buenos Aires, Argentina
| | - Fernando F Muñoz
- Biological Research Institute, National Council of Scientific and Technique Research (IIB-CONICET), Funes 3250 7600, Mar del Plata, Argentina; National University of Mar del Plata, School of Science, 7600 Mar del Plata, Argentina
| | - Jorge Zoppi
- Hospital of Community. Laboratory of Pathology B7602CMB Mar del Plata, Argentina
| | - Ricardo A Abaurrea
- Laboratory of Clinical and Bacteriological Analysis (BAS), 7600 Mar del Plata, Argentina
| | - Eduardo A Scandogliero
- Laboratory of Clinical and Bacteriological Analysis (BAS), 7600 Mar del Plata, Argentina
| | - Hebe Durán
- Institute of Nanoscience and Nanotechnology (INN), National Atomic Energy Commission (CNEA), National Scientific and Technical Research Council (CONICET), Constituyentes Node, Av. General Paz 1499, (B1650KNA) San Martín, Buenos Aires, Argentina.
| | - María Gabriela Guevara
- Biological Research Institute, National Council of Scientific and Technique Research (IIB-CONICET), Funes 3250 7600, Mar del Plata, Argentina; National University of Mar del Plata, School of Science, 7600 Mar del Plata, Argentina.
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Figueiredo L, Santos RB, Figueiredo A. Defense and Offense Strategies: The Role of Aspartic Proteases in Plant-Pathogen Interactions. BIOLOGY 2021; 10:75. [PMID: 33494266 PMCID: PMC7909840 DOI: 10.3390/biology10020075] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/08/2021] [Accepted: 01/19/2021] [Indexed: 12/23/2022]
Abstract
Plant aspartic proteases (APs; E.C.3.4.23) are a group of proteolytic enzymes widely distributed among different species characterized by the conserved sequence Asp-Gly-Thr at the active site. With a broad spectrum of biological roles, plant APs are suggested to undergo functional specialization and to be crucial in developmental processes, such as in both biotic and abiotic stress responses. Over the last decade, an increasing number of publications highlighted the APs' involvement in plant defense responses against a diversity of stresses. In contrast, few studies regarding pathogen-secreted APs and AP inhibitors have been published so far. In this review, we provide a comprehensive picture of aspartic proteases from plant and pathogenic origins, focusing on their relevance and participation in defense and offense strategies in plant-pathogen interactions.
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Hackett JC. PSI relieves the pressure of membrane fusion. J Biol Chem 2020; 295:14563-14564. [PMID: 33097646 DOI: 10.1074/jbc.h120.016038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Some plant proteases contain a latent sequence known as the plant-specific insert (PSI) that, upon release from the full protease sequence, initiates membrane fusion to defend from pathogens. However, the mechanism by which it exerts its effects has been unclear. Zhao et al. report an elegant integration of biophysical experiments and molecular dynamics simulations to reveal events leading up to PSI-mediated membrane fusion. Their results demonstrate a pH-dependent monomer-to-dimer transition, clear evidence of membrane association, and probable structures of prefusion intermediates. These data expand our understanding of the elusive PSIs and may provide new directions for antimicrobial development.
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Affiliation(s)
- John C Hackett
- Department of Physiology and Biophysics and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA.
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Dupuis JH, Wang S, Song C, Yada RY. The role of disulfide bonds in a Solanum tuberosum saposin-like protein investigated using molecular dynamics. PLoS One 2020; 15:e0237884. [PMID: 32841243 PMCID: PMC7447066 DOI: 10.1371/journal.pone.0237884] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/04/2020] [Indexed: 01/31/2023] Open
Abstract
The Solanum tuberosum plant specific insert (StPSI) has a defensive role in potato plants, with the requirements of acidic pH and anionic lipids. The StPSI contains a set of three highly conserved disulfide bonds that bridge the protein’s helical domains. Removal of these bonds leads to enhanced membrane interactions. This work examined the effects of their sequential removal, both individually and in combination, using all-atom molecular dynamics to elucidate the role of disulfide linkages in maintaining overall protein tertiary structure. The tertiary structure was found to remain stable at both acidic (active) and neutral (inactive) pH despite the removal of disulfide linkages. The findings include how the dimer structure is stabilized and the impact on secondary structure on a residue-basis as a function of disulfide bond removal. The StPSI possesses an extensive network of inter-monomer hydrophobic interactions and intra-monomer hydrogen bonds, which is likely the key to the stability of the StPSI by stabilizing local secondary structure and the tertiary saposin-fold, leading to a robust association between monomers, regardless of the disulfide bond state. Removal of disulfide bonds did not significantly impact secondary structure, nor lead to quaternary structural changes. Instead, disulfide bond removal induces regions of amino acids with relatively higher or lower variation in secondary structure, relative to when all the disulfide bonds are intact. Although disulfide bonds are not required to preserve overall secondary structure, they may have an important role in maintaining a less plastic structure within plant cells in order to regulate membrane affinity or targeting.
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Affiliation(s)
- John H. Dupuis
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Shenlin Wang
- College of Chemistry and Molecular Engineering and Beijing NMR Center, Peking University, Beijing, People's Republic of China
| | - Chen Song
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, People’s Republic of China
| | - Rickey Y. Yada
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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