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Muñoz-Vargas MA, Taboada J, González-Gordo S, Palma JM, Corpas FJ. Characterization of leucine aminopeptidase (LAP) activity in sweet pepper fruits during ripening and its inhibition by nitration and reducing events. PLANT CELL REPORTS 2024; 43:92. [PMID: 38466441 PMCID: PMC10927865 DOI: 10.1007/s00299-024-03179-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 02/22/2024] [Indexed: 03/13/2024]
Abstract
KEY MESSAGE Pepper fruits contain two leucine aminopeptidase (LAP) genes which are differentially modulated during ripening and by nitric oxide. The LAP activity increases during ripening but is negatively modulated by nitration. Leucine aminopeptidase (LAP) is an essential metalloenzyme that cleaves N-terminal leucine residues from proteins but also metabolizes dipeptides and tripeptides. LAPs play a fundamental role in cell protein turnover and participate in physiological processes such as defense mechanisms against biotic and abiotic stresses, but little is known about their involvement in fruit physiology. This study aims to identify and characterize genes encoding LAP and evaluate their role during the ripening of pepper (Capsicum annuum L.) fruits and under a nitric oxide (NO)-enriched environment. Using a data-mining approach of the pepper plant genome and fruit transcriptome (RNA-seq), two LAP genes, designated CaLAP1 and CaLAP2, were identified. The time course expression analysis of these genes during different fruit ripening stages showed that whereas CaLAP1 decreased, CaLAP2 was upregulated. However, under an exogenous NO treatment of fruits, both genes were downregulated. On the contrary, it was shown that during fruit ripening LAP activity increased by 81%. An in vitro assay of the LAP activity in the presence of different modulating compounds including peroxynitrite (ONOO-), NO donors (S-nitrosoglutathione and nitrosocyteine), reducing agents such as reduced glutathione (GSH), L-cysteine (L-Cys), and cyanide triggered a differential response. Thus, peroxynitrite and reducing compounds provoked around 50% inhibition of the LAP activity in green immature fruits, whereas cyanide upregulated it 1.5 folds. To our knowledge, this is the first characterization of LAP in pepper fruits as well as of its regulation by diverse modulating compounds. Based on the capacity of LAP to metabolize dipeptides and tripeptides, it could be hypothesized that the LAP might be involved in the GSH recycling during the ripening process.
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Affiliation(s)
- María A Muñoz-Vargas
- Department of Stress, Development and Signaling in Plants, Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Estación Experimental del Zaidín Spanish National Research Council, CSIC, C/Profesor Albareda, 1, 18008, Granada, Spain
| | - Jorge Taboada
- Department of Stress, Development and Signaling in Plants, Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Estación Experimental del Zaidín Spanish National Research Council, CSIC, C/Profesor Albareda, 1, 18008, Granada, Spain
| | - Salvador González-Gordo
- Department of Stress, Development and Signaling in Plants, Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Estación Experimental del Zaidín Spanish National Research Council, CSIC, C/Profesor Albareda, 1, 18008, Granada, Spain
| | - José M Palma
- Department of Stress, Development and Signaling in Plants, Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Estación Experimental del Zaidín Spanish National Research Council, CSIC, C/Profesor Albareda, 1, 18008, Granada, Spain
| | - Francisco J Corpas
- Department of Stress, Development and Signaling in Plants, Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Estación Experimental del Zaidín Spanish National Research Council, CSIC, C/Profesor Albareda, 1, 18008, Granada, Spain.
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Aguado ME, Izquierdo M, González-Matos M, Varela AC, Méndez Y, Del Rivero MA, Rivera DG, González-Bacerio J. Parasite Metalo-aminopeptidases as Targets in Human Infectious Diseases. Curr Drug Targets 2023; 24:416-461. [PMID: 36825701 DOI: 10.2174/1389450124666230224140724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 12/25/2022] [Accepted: 01/02/2023] [Indexed: 02/25/2023]
Abstract
BACKGROUND Parasitic human infectious diseases are a worldwide health problem due to the increased resistance to conventional drugs. For this reason, the identification of novel molecular targets and the discovery of new chemotherapeutic agents are urgently required. Metalo- aminopeptidases are promising targets in parasitic infections. They participate in crucial processes for parasite growth and pathogenesis. OBJECTIVE In this review, we describe the structural, functional and kinetic properties, and inhibitors, of several parasite metalo-aminopeptidases, for their use as targets in parasitic diseases. CONCLUSION Plasmodium falciparum M1 and M17 aminopeptidases are essential enzymes for parasite development, and M18 aminopeptidase could be involved in hemoglobin digestion and erythrocyte invasion and egression. Trypanosoma cruzi, T. brucei and Leishmania major acidic M17 aminopeptidases can play a nutritional role. T. brucei basic M17 aminopeptidase down-regulation delays the cytokinesis. The inhibition of Leishmania basic M17 aminopeptidase could affect parasite viability. L. donovani methionyl aminopeptidase inhibition prevents apoptosis but not the parasite death. Decrease in Acanthamoeba castellanii M17 aminopeptidase activity produces cell wall structural modifications and encystation inhibition. Inhibition of Babesia bovis growth is probably related to the inhibition of the parasite M17 aminopeptidase, probably involved in host hemoglobin degradation. Schistosoma mansoni M17 aminopeptidases inhibition may affect parasite development, since they could participate in hemoglobin degradation, surface membrane remodeling and eggs hatching. Toxoplasma gondii M17 aminopeptidase inhibition could attenuate parasite virulence, since it is apparently involved in the hydrolysis of cathepsin Cs- or proteasome-produced dipeptides and/or cell attachment/invasion processes. These data are relevant to validate these enzymes as targets.
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Affiliation(s)
- Mirtha E Aguado
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
| | - Maikel Izquierdo
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
| | - Maikel González-Matos
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
| | - Ana C Varela
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
| | - Yanira Méndez
- Center for Natural Products Research, Faculty of Chemistry, University of Havana, Zapata y G, 10400, La Habana, Cuba
| | - Maday A Del Rivero
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
| | - Daniel G Rivera
- Center for Natural Products Research, Faculty of Chemistry, University of Havana, Zapata y G, 10400, La Habana, Cuba
| | - Jorge González-Bacerio
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
- Department of Biochemistry, Faculty of Biology, University of Havana, calle 25 #455 entre I y J, 10400, Vedado, La Habana, Cuba
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Phosphinotripeptidic Inhibitors of Leucylaminopeptidases. Int J Mol Sci 2021; 22:ijms22105090. [PMID: 34065004 PMCID: PMC8151835 DOI: 10.3390/ijms22105090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 04/28/2021] [Accepted: 05/06/2021] [Indexed: 12/02/2022] Open
Abstract
Phosphinate pseudopeptide are analogs of peptides containing phosphinate moiety in a place of the amide bond. Due to this, the organophosphorus fragment resembles the tetrahedral transition state of the amide bond hydrolysis. Additionally, it is also capable of coordinating metal ions, for example, zinc or magnesium ions. These two properties of phosphinate pseudopeptides make them an ideal candidate for metal-related protease inhibitors. This research investigates the influence of additional residue in the P2 position on the inhibitory properties of phosphinopeptides. The synthetic strategy is proposed, based on retrosynthetic analysis. The N-C-P bond formation in the desired compounds is conveniently available from the three-component condensation of appropriate amino components, aldehydes, and hypophosphorous acid. One of the crucial synthetic steps is the careful selection of the protecting groups for all the functionals. Determination of the inhibitor activity of the obtained compounds has been done using UV-Vis spectroscopy and standard substrate L-Leu-p-nitroanilide toward the enzymes isolated from the porcine kidney (SsLAP, Sus scrofa Leucine aminopeptidase) and barley seeds (HvLAP, Hordeum vulgare Leucine aminopeptidase). An efficient procedure for the preparation of phosphinotripeptides has been performed. Activity test shown that introduction of additional residue into P2 position obtains the micromolar range inhibitors of SsLAP and HvLAP. Moreover, careful selection of the residue in the P2 position should improve its selectivity toward mammalian and plant leucyl aminopeptidases.
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Malcolm TR, Belousoff MJ, Venugopal H, Borg NA, Drinkwater N, Atkinson SC, McGowan S. Active site metals mediate an oligomeric equilibrium in Plasmodium M17 aminopeptidases. J Biol Chem 2020; 296:100173. [PMID: 33303633 PMCID: PMC7948507 DOI: 10.1074/jbc.ra120.016313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 01/14/2023] Open
Abstract
M17 leucyl aminopeptidases are metal-dependent exopeptidases that rely on oligomerization to diversify their functional roles. The M17 aminopeptidases from Plasmodium falciparum (PfA-M17) and Plasmodium vivax (Pv-M17) function as catalytically active hexamers to generate free amino acids from human hemoglobin and are drug targets for the design of novel antimalarial agents. However, the molecular basis for oligomeric assembly is not fully understood. In this study, we found that the active site metal ions essential for catalytic activity have a secondary structural role mediating the formation of active hexamers. We found that PfA-M17 and Pv-M17 exist in a metal-dependent dynamic equilibrium between active hexameric species and smaller inactive species that can be controlled by manipulating the identity and concentration of metals available. Mutation of residues involved in metal ion binding impaired catalytic activity and the formation of active hexamers. Structural resolution of Pv-M17 by cryoelectron microscopy and X-ray crystallography together with solution studies revealed that PfA-M17 and Pv-M17 bind metal ions and substrates in a conserved fashion, although Pv-M17 forms the active hexamer more readily and processes substrates faster than PfA-M17. On the basis of these studies, we propose a dynamic equilibrium between monomer ↔ dimer ↔ tetramer ↔ hexamer, which becomes directional toward the large oligomeric states with the addition of metal ions. This sophisticated metal-dependent dynamic equilibrium may apply to other M17 aminopeptidases and underpin the moonlighting capabilities of this enzyme family.
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Affiliation(s)
- Tess R Malcolm
- Infection & Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Matthew J Belousoff
- Infection & Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Hariprasad Venugopal
- Ramacciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Victoria, Australia
| | - Natalie A Borg
- Infection & Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia; Immunity and Immune Evasion Laboratory, Chronic Infectious and Inflammatory Diseases Research, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Nyssa Drinkwater
- Infection & Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Sarah C Atkinson
- Infection & Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia; Immunity and Immune Evasion Laboratory, Chronic Infectious and Inflammatory Diseases Research, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Sheena McGowan
- Infection & Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia.
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N-Benzyl Residues as the P1' Substituents in Phosphorus-Containing Extended Transition State Analog Inhibitors of Metalloaminopeptidases. Molecules 2020; 25:molecules25184334. [PMID: 32971789 PMCID: PMC7571175 DOI: 10.3390/molecules25184334] [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: 08/28/2020] [Revised: 09/18/2020] [Accepted: 09/19/2020] [Indexed: 12/31/2022] Open
Abstract
Peptidyl enzyme inhibitors containing an internal aminomethylphosphinic bond system (P(O)(OH)-CH2-NH) can be termed extended transition state analogs by similarity to the corresponding phosphonamidates (P(O)(OH)-NH). Phosphonamidate pseudopeptides are broadly recognized as competitive mechanism-based inhibitors of metalloenzymes, mainly hydrolases. Their practical use is, however, limited by hydrolytic instability, which is particularly restricting for dipeptide analogs. Extension of phosphonamidates by addition of the methylene group produces a P-C-N system fully resistant in water conditions. In the current work, we present a versatile synthetic approach to such modified dipeptides, based on the three-component phospha-Mannich condensation of phosphinic acids, formaldehyde, and N-benzylglycines. The last-mentioned component allowed for simple and versatile introduction of functionalized P1′ residues located on the tertiary amino group. The products demonstrated moderate inhibitory activity towards porcine and plant metalloaminopeptidases, while selected derivatives appeared very potent with human alanyl aminopeptidase (Ki = 102 nM for 6a). Analysis of ligand-protein complexes obtained by molecular modelling revealed canonical modes of interactions for mono-metallic alanyl aminopeptidases, and distorted modes for di-metallic leucine aminopeptidases (with C-terminal carboxylate, not phosphinate, involved in metal coordination). In general, the method can be dedicated to examine P1′-S1′ complementarity in searching for non-evident structures of specific residues as the key fragments of perspective ligands.
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P1' Residue-Oriented Virtual Screening for Potent and Selective Phosphinic (Dehydro) Dipeptide Inhibitors of Metallo-Aminopeptidases. Biomolecules 2020; 10:biom10040659. [PMID: 32344658 PMCID: PMC7225938 DOI: 10.3390/biom10040659] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/17/2020] [Accepted: 04/20/2020] [Indexed: 01/01/2023] Open
Abstract
Designing side chain substituents complementary to enzyme binding pockets is of great importance in the construction of potent and selective phosphinic dipeptide inhibitors of metallo-aminopeptidases. Proper structure selection makes inhibitor construction more economic, as the development process typically consists of multiple iterative preparation/bioassay steps. On the basis of these principles, using noncomplex computation and modeling methodologies, we comprehensively screened 900 commercial precursors of the P1′ residues of phosphinic dipeptide and dehydrodipeptide analogs to identify the most promising ligands of 52 metallo-dependent aminopeptidases with known crystal structures. The results revealed several nonproteinogenic residues with an improved energy of binding compared with the best known inhibitors. The data are discussed taking into account the selectivity and stereochemical implications of the enzymes. Using this approach, we were able to identify nontrivial structural elements substituting the recognized phosphinic peptidomimetic scaffold of metallo-aminopeptidase inhibitors.
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Drinkwater N, Malcolm TR, McGowan S. M17 aminopeptidases diversify function by moderating their macromolecular assemblies and active site environment. Biochimie 2019; 166:38-51. [DOI: 10.1016/j.biochi.2019.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/10/2019] [Indexed: 12/24/2022]
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Phosphonic Acid Analogues of Phenylglycine as Inhibitors of Aminopeptidases: Comparison of Porcine Aminopeptidase N, Bovine Leucine Aminopeptidase, Tomato Acidic Leucine Aminopeptidase and Aminopeptidase from Barley Seeds. Pharmaceuticals (Basel) 2019; 12:ph12030139. [PMID: 31533309 PMCID: PMC6789573 DOI: 10.3390/ph12030139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 12/22/2022] Open
Abstract
The inhibitory activity of 14 racemic phosphonic acid analogs of phenylglycine, substituted in aromatic rings, towards porcine aminopeptidase N (pAPN) and barley seed aminopeptidase was determined experimentally. The obtained patterns of the inhibitory activity against the two enzymes were similar. The obtained data served as a basis for studying the binding modes of these inhibitors by pAPN using molecular modeling. It was found that their aminophosphonate fragments were bound in a highly uniform manner and that the difference in their affinities most likely resulted from the mode of substitution of their phenyl rings. The obtained binding modes towards pAPN were compared, with these predicted for bovine lens leucine aminopeptidase (blLAP) and tomato acidic leucine aminopeptidase (tLAPA). The performed studies indicated that the binding manner of the phenylglycine analogs to biLAP and tLAPA are significantly similar and differ slightly from that predicted for pAPN.
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Park SY, Scranton MA, Stajich JE, Yee A, Walling LL. Chlorophyte aspartyl aminopeptidases: Ancient origins, expanded families, new locations, and secondary functions. PLoS One 2017; 12:e0185492. [PMID: 29023459 PMCID: PMC5638241 DOI: 10.1371/journal.pone.0185492] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 09/13/2017] [Indexed: 11/19/2022] Open
Abstract
M18 aspartyl aminopeptidases (DAPs) are well characterized in microbes and animals with likely functions in peptide processing and vesicle trafficking. In contrast, there is a dearth of knowledge on plant aminopeptidases with a preference for proteins and peptides with N-terminal acidic residues. During evolution of the Plantae, there was an expansion and diversification of the M18 DAPs. After divergence of the ancestral green algae from red and glaucophyte algae, a duplication yielded the DAP1 and DAP2 lineages. Subsequently DAP1 genes were lost in chlorophyte algae. A duplication of DAP2-related genes occurred early in green plant evolution. DAP2 genes were retained in land plants and picoeukaryotic algae and lost in green algae. In contrast, DAP2-like genes persisted in picoeukaryotic and green algae, while this lineage was lost in land plants. Consistent with this evolutionary path, Arabidopsis thaliana has two DAP gene lineages (AtDAP1 and AtDAP2). Similar to animal and yeast DAPs, AtDAP1 is localized to the cytosol or vacuole; while AtDAP2 harbors an N-terminal transit peptide and is chloroplast localized. His6-DAP1 and His6-DAP2 expressed in Escherichia coli were enzymatically active and dodecameric with masses exceeding 600 kDa. His6-DAP1 and His6-DAP2 preferentially hydrolyzed Asp-p-nitroanilide and Glu-p-nitroanilide. AtDAPs are highly conserved metallopeptidases activated by MnCl2 and inhibited by ZnCl2 and divalent ion chelators. The protease inhibitor PMSF inhibited and DTT stimulated both His6-DAP1 and His6-DAP2 activities suggesting a role for thiols in the AtDAP catalytic mechanism. The enzymes had distinct pH and temperature optima, as well as distinct kinetic parameters. Both enzymes had high catalytic efficiencies (kcat/Km) exceeding 1.0 x 107 M-1 sec-1. Using established molecular chaperone assays, AtDAP1 and AtDAP2 prevented thermal denaturation. AtDAP1 also prevented protein aggregation and promoted protein refolding. Collectively, these data indicate that plant DAPs have a complex evolutionary history and have evolved new biochemical features that may enable their role in vivo.
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Affiliation(s)
- Sang-Youl Park
- Department of Botany and Plant Sciences, Center for Plant Cell Biology, University of California, Riverside, California, United States of America
| | - Melissa A. Scranton
- Department of Botany and Plant Sciences, Center for Plant Cell Biology, University of California, Riverside, California, United States of America
| | - Jason E. Stajich
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology, University of California, Riverside, California, United States of America
| | - Ashley Yee
- Department of Botany and Plant Sciences, Center for Plant Cell Biology, University of California, Riverside, California, United States of America
| | - Linda L. Walling
- Department of Botany and Plant Sciences, Center for Plant Cell Biology, University of California, Riverside, California, United States of America
- * E-mail:
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DuPrez KT, Scranton MA, Walling LL, Fan L. Structural insights into chaperone-activity enhancement by a K354E mutation in tomato acidic leucine aminopeptidase. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2016; 72:694-702. [DOI: 10.1107/s205979831600509x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 03/24/2016] [Indexed: 11/10/2022]
Abstract
Tomato plants express acidic leucine aminopeptidase (LAP-A) in response to various environmental stressors. LAP-A not only functions as a peptidase for diverse peptide substrates, but also displays chaperone activity. A K354E mutation has been shown to abolish the peptidase activity but to enhance the chaperone activity of LAP-A. To better understand this moonlighting function of LAP-A, the crystal structure of the K354E mutant was determined at 2.15 Å resolution. The structure reveals that the K354E mutation destabilizes an active-site loop and causes significant rearrangement of active-site residues, leading to loss of the catalytic metal-ion coordination required for the peptidase activity. Although the mutant was crystallized in the same hexameric form as wild-type LAP-A, gel-filtration chromatography revealed an apparent shift from the hexamer to lower-order oligomers for the K354E mutant, showing a mixture of monomers to trimers in solution. In addition, surface-probing assays indicated that the K354E mutant has more accessible hydrophobic areas than wild-type LAP-A. Consistently, computational thermodynamic estimations of the interfaces between LAP-A monomers suggest that increased exposure of hydrophobic surfaces occurs upon hexamer breakdown. These results suggest that the K354E mutation disrupts the active-site loop, which also contributes to the hexameric assembly, and destabilizes the hexamers, resulting in much greater hydrophobic areas accessible for efficient chaperone activity than in the wild-type LAP-A.
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Modak JK, Rut W, Wijeyewickrema LC, Pike RN, Drag M, Roujeinikova A. Structural basis for substrate specificity of Helicobacter pylori M17 aminopeptidase. Biochimie 2015; 121:60-71. [PMID: 26616008 DOI: 10.1016/j.biochi.2015.11.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 11/20/2015] [Indexed: 11/25/2022]
Abstract
The M17 aminopeptidase from the carcinogenic gastric bacterium Helicobacter pylori (HpM17AP) is an important housekeeping enzyme involved in catabolism of endogenous and exogenous peptides. It is implicated in H. pylori defence against the human innate immune response and in the mechanism of metronidazole resistance. Bestatin inhibits HpM17AP and suppresses H. pylori growth. To address the structural basis of catalysis and inhibition of this enzyme, we have established its specificity towards the N-terminal amino acid of peptide substrates and determined the crystal structures of HpM17AP and its complex with bestatin. The position of the D-phenylalanine moiety of the inhibitor with respect to the active-site metal ions, bicarbonate ion and with respect to other M17 aminopeptidases suggested that this residue binds to the S1 subsite of HpM17AP. In contrast to most characterized M17 aminopeptidases, HpM17AP displays preference for L-Arg over L-Leu residues in peptide substrates. Compared to very similar homologues from other bacteria, a distinguishing feature of HpM17AP is a hydrophilic pocket at the end of the S1 subsite that is likely to accommodate the charged head group of the L-Arg residue of the substrate. The pocket is flanked by a sodium ion (not present in M17 aminopeptidases that show preference for L-Leu) and its coordinating water molecules. In addition, the structure suggests that variable loops at the entrance to, and in the middle of, the substrate-binding channel are important determinants of substrate specificity of M17 aminopeptidases.
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Affiliation(s)
- Joyanta K Modak
- Infection and Immunity Program, Monash Biomedical Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Wioletta Rut
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Technology, Wroclaw, Poland
| | - Lakshmi C Wijeyewickrema
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Robert N Pike
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Marcin Drag
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Technology, Wroclaw, Poland
| | - Anna Roujeinikova
- Infection and Immunity Program, Monash Biomedical Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
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