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Dürvanger Z, Juhász T, Liliom K, Harmat V. Structures of calmodulin-melittin complexes show multiple binding modes lacking classical anchoring interactions. J Biol Chem 2023; 299:104596. [PMID: 36906144 PMCID: PMC10140167 DOI: 10.1016/j.jbc.2023.104596] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/11/2023] Open
Abstract
Calmodulin (CaM) is a Ca2+ sensor protein found in all eukaryotic cells that regulates a large number of target proteins in a Ca2+ concentration-dependent manner. As a transient type hub protein, it recognizes linear motifs of its targets, though for the Ca2+-dependent binding no consensus sequence was identified. Its complex with melittin, a major component of bee venom, is often used as a model system of protein - protein complexes. Yet, the structural aspects of the binding are not well understood, as only diverse, low-resolution data are available concerning the association. We present the crystal structure of melittin in complex with Ca2+-saturated calmodulins from two, evolutionarily distant species, Homo sapiens and Plasmodium falciparum representing three binding modes of the peptide. Results - augmented by molecular dynamics simulations - indicate that multiple binding modes can exist for CaM-melittin complexes, as an intrinsic characteristic of the binding. While the helical structure of melittin remains, swapping of its salt bridges and partial unfolding of its C-terminal segment can occur. In contrast to the classical way of target recognition by CaM, we found that different sets of residues can anchor at the hydrophobic pockets of CaM, which were considered as main recognition sites. Finally, the nanomolar binding affinity of the CaM-melittin complex is created by an ensemble of arrangements of similar stability - tight binding is achieved not by optimized specific interactions but by simultaneously satisfying less optimal interaction patterns in co-existing different conformers.
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Affiliation(s)
- Zsolt Dürvanger
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Tünde Juhász
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Budapest, Hungary
| | - Károly Liliom
- Department of Biophysics and Radiation Biology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Veronika Harmat
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, ELTE Eötvös Loránd University, Budapest, Hungary; ELKH-ELTE Protein Modelling Research Group, Eötvös Loránd Research Network, Budapest, Hungary.
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2
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What Is Parvalbumin for? Biomolecules 2022; 12:biom12050656. [PMID: 35625584 PMCID: PMC9138604 DOI: 10.3390/biom12050656] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/25/2022] [Accepted: 04/28/2022] [Indexed: 12/28/2022] Open
Abstract
Parvalbumin (PA) is a small, acidic, mostly cytosolic Ca2+-binding protein of the EF-hand superfamily. Structural and physical properties of PA are well studied but recently two highly conserved structural motifs consisting of three amino acids each (clusters I and II), which contribute to the hydrophobic core of the EF-hand domains, have been revealed. Despite several decades of studies, physiological functions of PA are still poorly known. Since no target proteins have been revealed for PA so far, it is believed that PA acts as a slow calcium buffer. Numerous experiments on various muscle systems have shown that PA accelerates the relaxation of fast skeletal muscles. It has been found that oxidation of PA by reactive oxygen species (ROS) is conformation-dependent and one more physiological function of PA in fast muscles could be a protection of these cells from ROS. PA is thought to regulate calcium-dependent metabolic and electric processes within the population of gamma-aminobutyric acid (GABA) neurons. Genetic elimination of PA results in changes in GABAergic synaptic transmission. Mammalian oncomodulin (OM), the β isoform of PA, is expressed mostly in cochlear outer hair cells and in vestibular hair cells. OM knockout mice lose their hearing after 3–4 months. It was suggested that, in sensory cells, OM maintains auditory function, most likely affecting outer hair cells’ motility mechanisms.
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3
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Troilo F, Pedretti M, Travaglini-Allocatelli C, Astegno A, Di Matteo A. Rapid kinetics of calcium dissociation from plant calmodulin and calmodulin-like proteins and effect of target peptides. Biochem Biophys Res Commun 2022; 590:103-108. [PMID: 34974297 DOI: 10.1016/j.bbrc.2021.12.077] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 12/21/2021] [Indexed: 11/02/2022]
Abstract
Calcium (Ca2+) signaling represents a universal information code in plants, playing crucial roles spanning developmental processes to stress responses. Ca2+ signals are decoded into defined plant adaptive responses by different Ca2+ sensing proteins, including calmodulin (CaM) and calmodulin-like (CML) proteins. Although major advances have been achieved in describing how these Ca2+ decoding proteins interact and regulate downstream target effectors, the molecular details of these processes remain largely unknown. Herein, the kinetics of Ca2+ dissociation from a conserved CaM and two CML isoforms from A. thaliana has been studied by fluorescence stopped-flow spectroscopy. Kinetic data were obtained for the isolated Ca2+-bound proteins as well as for the proteins complexed with different target peptides. Moreover, the lobe specific interactions between the Ca2+ sensing proteins and their targets were characterized by using a panel of protein mutants deficient in Ca2+ binding at the N-lobe or C-lobe. Results were analyzed and discussed in the context of the Ca2+-decoding and Ca2+-controlled target binding mechanisms in plants.
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Affiliation(s)
- Francesca Troilo
- CNR Institute of Molecular Biology and Pathology, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Marco Pedretti
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
| | | | - Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy.
| | - Adele Di Matteo
- CNR Institute of Molecular Biology and Pathology, P.le Aldo Moro 5, 00185, Rome, Italy.
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4
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Juhász T, Kardos J, Dürvanger Z, Harmat V, Liliom K. Comparison of ligand binding and conformational stability of human calmodulin with its homolog from the malaria parasite Plasmodium falciparum. FASEB Bioadv 2020; 2:489-505. [PMID: 32821880 PMCID: PMC7429351 DOI: 10.1096/fba.2020-00013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 03/24/2020] [Accepted: 06/16/2020] [Indexed: 11/11/2022] Open
Abstract
Calmodulin (CaM), the key calcium sensor of eukaryotic cells regulating a great number of target proteins, belongs to the most conserved proteins. We compared function and properties of CaMs from two evolutionarily distant species, the human (Homo sapiens) representing vertebrates, and the malaria parasite Plasmodium falciparum (Pf). The biophysical characterization revealed higher stability of Pf CaM attributed to the more stable C-terminal domain in both Ca2+ free and saturated states. In vitro binding and functional assays demonstrated that human and Pf CaM exhibit similar biochemical features involving small molecule inhibitor binding and target enzyme activation as illustrated by comparable affinities differing only within a factor of three. It has been reported that CaM antagonists proved to be antimalarials, so Pf CaM could be a potential target to combat malaria parasites. Indeed, we observed that phenotypically active compounds from the Malaria Box could show inhibitory action on Pf CaM, among them the most potent exhibited comparable inhibition to known antagonists of vertebrate CaM. However, based on the minor binding differences in Pf CaM to human CaM, we conclude that CaM is an unsuited target for human intervention against malaria, due to the likely interference with the host protein.
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Affiliation(s)
- Tünde Juhász
- Institute of Materials and Environmental ChemistryResearch Centre for Natural SciencesBudapestHungary
| | - József Kardos
- Department of BiochemistryInstitute of BiologyELTE Eötvös Loránd UniversityBudapestHungary
| | - Zsolt Dürvanger
- Laboratory of Structural Chemistry and BiologyInstitute of ChemistryEötvös Loránd UniversityBudapestHungary
| | - Veronika Harmat
- Laboratory of Structural Chemistry and BiologyInstitute of ChemistryEötvös Loránd UniversityBudapestHungary
- MTA‐ELTE Protein Modelling Research GroupBudapestHungary
| | - Károly Liliom
- Department of Biophysics and Radiation BiologyFaculty of MedicineSemmelweis UniversityBudapestHungary
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5
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Trande M, Pedretti M, Bonza MC, Di Matteo A, D'Onofrio M, Dominici P, Astegno A. Cation and peptide binding properties of CML7, a calmodulin-like protein from Arabidopsis thaliana. J Inorg Biochem 2019; 199:110796. [PMID: 31419675 DOI: 10.1016/j.jinorgbio.2019.110796] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/26/2019] [Accepted: 07/31/2019] [Indexed: 12/12/2022]
Abstract
Plants contain a large family of so-called calmodulin-like proteins (CMLs) which differ from canonical calmodulin in that they show greater variability in sequence, length, and number of EF-hand domains. The presence of this extended CML family has raised questions regarding the role of these proteins: are they functionally redundant or do they play specific functions in physiological plant processes? To answer these questions, comprehensive biochemical and structural information on CML proteins is fundamental. Among the 50 CMLs from Arabidopsis thaliana, herein we described the ability of CML7 to bind metal ions focusing on the Ca2+ and Mg2+ sensing properties, as well as on metal-induced conformational changes. Circular dichroism and nuclear magnetic resonance (NMR) studies indicated that both Ca2+ and Mg2+ stabilize CML7, as reflected in conformational rearrangements in secondary and tertiary structure and in increases in thermal stability of the protein. However, the conformational changes that binding induces differ between the two metal ions, and only Ca2+ binding controls a structural transition that leads to hydrophobic exposure, as suggested by 8-anilino-1-naphthalenesulfonic acid fluorescence. Isothermal titration calorimetry data coupled with NMR experiments revealed the presence of two high affinity Ca2+-binding sites in the C-lobe of CML7 and two weaker sites in the N-lobe. The paired nature of these CML7 EF-hands enables them to bind Ca2+ with positive cooperativity within each globular domain. Our results clearly place CML7 in the category of Ca2+ sensors. Along with this, the protein can bind to a model target peptide (melittin) in a Ca2+-dependent manner.
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Affiliation(s)
- Matteo Trande
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Marco Pedretti
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Maria Cristina Bonza
- Department of Biosciences, University of Milano, Via Celoria 26, 20133 Milano, Italy
| | - Adele Di Matteo
- Institute of Molecular Biology and Pathology, CNR, Piazzale Aldo Moro 5, Roma 00185, Italy
| | - Mariapina D'Onofrio
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Paola Dominici
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy.
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6
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Liu XR, Zhang MM, Rempel DL, Gross ML. Protein-Ligand Interaction by Ligand Titration, Fast Photochemical Oxidation of Proteins and Mass Spectrometry: LITPOMS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:213-217. [PMID: 30484077 PMCID: PMC6438201 DOI: 10.1007/s13361-018-2076-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 09/19/2018] [Accepted: 09/23/2018] [Indexed: 05/03/2023]
Abstract
We report a novel method named LITPOMS (ligand titration, fast photochemical oxidation of proteins and mass spectrometry) to characterize protein-ligand binding stoichiometry, binding sites, and site-specific binding constants. The system used to test the method is melittin-calmodulin, in which the peptide melittin binds to calcium-bound calmodulin. Global-level measurements reveal the binding stoichiometry of 1:1 whereas peptide-level data coupled with fitting reveal the binding sites and the site-specific binding affinity. Moreover, we extended the analysis to the residue level and identified six critical binding residues. The results show that melittin binds to the N-terminal, central linker, and C-terminal regions of holo-calmodulin with an affinity of 4.6 nM, in agreement with results of previous studies. LITPOMS, for the first time, brings high residue-level resolution to affinity measurements, providing simultaneously qualitative and quantitative understanding of protein-ligand binding. The approach can be expanded to other binding systems without tagging the protein to give high spatial resolution. Graphical Abstract.
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Affiliation(s)
- Xiaoran Roger Liu
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA
| | - Mengru Mira Zhang
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA
| | - Don L Rempel
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA.
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7
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Inhibitory effect of melittin on endonuclease-like activity of centrin. J Inorg Biochem 2018; 186:280-293. [PMID: 29990752 DOI: 10.1016/j.jinorgbio.2018.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/09/2018] [Accepted: 07/01/2018] [Indexed: 11/21/2022]
Abstract
The xeroderma pigmentosum group C protein (XPC) and centrin2 are the primary initiators of global genome nucleotide excision repair (NER). Centrin, acts as a member of the EF-hand super family of calcium-binding proteins, playing roles in reconstitution of the vitro NER reaction. To understand the possible molecular and structural properties of the multiprotein process, the interactions of Euplotes octocarinatus centrin (EoCen), melittin, and DNA are described. EoCen shares a sequence identity of 66% with centrin2. Melittin possesses inverse direction hydrophobic triads-leucine-leucine-tryptophan (LLW) which are responsible for centrin binding. It is applied as a natural peptide to mimic centrin target peptide. As a result, it is proved that the integrated protein shows an endonuclease-like activity to DNA. Melittin is capable of interaction with both EoCen and DNA. More importantly, it is found that melittin displays an inhibitory effect on the endonuclease-like activity of centrin when it co-exists with EoCen and DNA in solution. Meanwhile, the DNA-melittin-EoCen ternary complex forms in the process. Quantitative analyses demonstrated by extensive biophysical assays reveal that binding of the peptide to DNA or centrin modulates the binding properties of it to another component. Furthermore, a possible positioning model of DNA and EoCen on melittin is proposed. This finding may constitute a model for that existing between centrin and its target peptide in NER process.
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8
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Ramirez L, Shekhtman A, Pande J. Nuclear Magnetic Resonance-Based Structural Characterization and Backbone Dynamics of Recombinant Bee Venom Melittin. Biochemistry 2018; 57:2775-2785. [PMID: 29668274 DOI: 10.1021/acs.biochem.8b00156] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In recent years, there has been a resurgence of interest in melittin and its variants as their therapeutic potential has become increasingly evident. Melittin is a 26-residue peptide and a toxic component of honey bee venom. The versatility of melittin in interacting with various biological substrates, such as membranes, glycosaminoglycans, and a variety of proteins, has inspired a slew of studies that aim to improve our understanding of the structural basis of such interactions. However, these studies have largely focused on melittin solutions at high concentrations (>1 mM), even though melittin is generally effective at lower (micromolar) concentrations. Here we present high-resolution nuclear magnetic resonance studies in the lower-concentration regime using a novel method to produce isotope-labeled (15N and 13C) recombinant melittin. We provide residue-specific structural characterization of melittin in dilute aqueous solution and in 2,2,2-trifluoroethanol/water mixtures, which mimic melittin structure-function and interactions in aqueous and membrane-like environments, respectively. We find that the cis-trans isomerization of Pro14 is key to changes in the secondary structure of melittin. Thus, this study provides residue-specific structural information about melittin in the free state and in a model of the substrate-bound state. These results, taken together with published work from other laboratories, reveal the peptide's structural versatility that resembles that of intrinsically disordered proteins and peptides.
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Affiliation(s)
- Lisa Ramirez
- Department of Chemistry , University at Albany, State University of New York , Albany , New York 12222 , United States
| | - Alexander Shekhtman
- Department of Chemistry , University at Albany, State University of New York , Albany , New York 12222 , United States
| | - Jayanti Pande
- Department of Chemistry , University at Albany, State University of New York , Albany , New York 12222 , United States
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9
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Shi E, Zhang W, Zhao Y, Yang B. Modulation of XPC peptide on binding Tb 3+ to Euplotes octocarinatus centrin. Metallomics 2017; 9:1796-1808. [PMID: 29114686 DOI: 10.1039/c7mt00263g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Centrins are Ca2+-binding proteins found throughout eukaryotic organisms. Xeroderma pigmentosum group C protein (XPC), a dominant component of the nuclear excision repair (NER) pathway, is a critical target protein of centrins. A 22-residue peptide (K842-R863) from XPC was used to investigate the effect of metal ions (Ca2+ and Tb3+) on the peptide binding of Euplotes octocarinatus centrin (EoCen) by isothermal titration calorimetry (ITC) and fluorescence spectroscopy. ITC and tryptophan spectrofluorimetric titrations revealed that metal ions (Ca2+ and Tb3+) could enhance the affinity between EoCen and the XPC peptide, and the enhanced effects were closely related to the ion potential of metal ions. Since the ion potential of Tb3+ (e/r = 0.0325) is larger than that of Ca2+ (e/r = 0.0202), the conformational change in the protein induced by Tb3+ is larger than that induced by Ca2+, and the enhanced affinity of Tb3+ is stronger than that of Ca2+. This interaction was driven by enthalpy in the presence of EDTA and enthalpy and entropy in the presence of Ca2+ or Tb3+. Similar to that observed in the presence of EDTA, the N-terminal domain did not participate in the interaction with the XPC peptide even in the presence of metal ions. Resonance light scattering (RLS) and the band shift in native polyacrylamide gel electrophoresis (PAGE) suggested that peptide binding resulted in the dissociation of EoCen aggregates and complex formation via the monomer-peptide form. Tb3+-Sensitized emission suggested that peptide binding in turn also had an impact on the Tb3+ binding of the protein: the C-terminal domain was slightly strengthened and the N-terminal domain was weakened about 225 fold. RLS and native PAGE indicated that the self-assembly induced by Tb3+ binding to the N-terminal domain of EoCen was inhibited in the presence of the XPC peptide. This study elucidates the molecular mechanism of EoCen function in the cellular context.
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Affiliation(s)
- Enxian Shi
- Institute of Molecular Science, Key Laboratory of Chemical Biology of Molecular Engineering of Education Ministry, Shanxi University, Taiyuan 030006, P. R. China. and Department of Pharmacy, Shanxi Medical University, Taiyuan 030001, P. R. China
| | - Wenlong Zhang
- Institute of Molecular Science, Key Laboratory of Chemical Biology of Molecular Engineering of Education Ministry, Shanxi University, Taiyuan 030006, P. R. China.
| | - Yaqin Zhao
- Institute of Molecular Science, Key Laboratory of Chemical Biology of Molecular Engineering of Education Ministry, Shanxi University, Taiyuan 030006, P. R. China.
| | - Binsheng Yang
- Institute of Molecular Science, Key Laboratory of Chemical Biology of Molecular Engineering of Education Ministry, Shanxi University, Taiyuan 030006, P. R. China.
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10
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The Calcium-Dependent Switch Helix of L-Plastin Regulates Actin Bundling. Sci Rep 2017; 7:40662. [PMID: 28145401 PMCID: PMC5286426 DOI: 10.1038/srep40662] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 12/09/2016] [Indexed: 01/14/2023] Open
Abstract
L-plastin is a calcium-regulated actin-bundling protein that is expressed in cells of hematopoietic origin and in most metastatic cancer cells. These cell types are mobile and require the constant remodeling of their actin cytoskeleton, where L-plastin bundles filamentous actin. The calcium-dependent regulation of the actin-bundling activity of L-plastin is not well understood. We have used NMR spectroscopy to determine the solution structure of the EF-hand calcium-sensor headpiece domain. Unexpectedly, this domain does not bind directly to the four CH-domains of L-plastin. A novel switch helix is present immediately after the calcium-binding region and it binds tightly to the EF-hand motifs in the presence of calcium. We demonstrate that this switch helix plays a major role during actin-bundling. Moreover a peptide that competitively inhibits the association between the EF-hand motifs and the switch helix was shown to deregulate the actin-bundling activity of L-plastin. Overall, these findings may help to develop new drugs that target the L-plastin headpiece and interfere in the metastatic activity of cancer cells.
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11
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Cifuentes-Pagano ME, Meijles DN, Pagano PJ. Nox Inhibitors & Therapies: Rational Design of Peptidic and Small Molecule Inhibitors. Curr Pharm Des 2016; 21:6023-35. [PMID: 26510437 DOI: 10.2174/1381612821666151029112013] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/27/2015] [Indexed: 12/15/2022]
Abstract
Oxidative stress-related diseases underlie many if not all of the major leading causes of death in United States and the Western World. Thus, enormous interest from both academia and pharmaceutical industry has been placed on the development of agents which attenuate oxidative stress. With that in mind, great efforts have been placed in the development of inhibitors of NADPH oxidase (Nox), the major enzymatic source of reactive oxygen species and oxidative stress in many cells and tissue. The regulation of a catalytically active Nox enzyme involves numerous protein-protein interactions which, in turn, afford numerous targets for inhibition of its activity. In this review, we will provide an updated overview of the available Nox inhibitors, both peptidic and small molecules, and discuss the body of data related to their possible mechanisms of action and specificity towards each of the various isoforms of Nox. Indeed, there have been some very notable successes. However, despite great commitment by many in the field, the need for efficacious and well-characterized, isoform-specific Nox inhibitors, essential for the treatment of major diseases as well as for delineating the contribution of a given Nox in physiological redox signalling, continues to grow.
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Affiliation(s)
| | | | - Patrick J Pagano
- Department of Pharmacology & Chemical Biology, Vascular Medicine Institute, University of Pittsburgh School of Medicine, Biomedical Science Tower, 12th Floor, Room E1247, 200 Lothrop St., Pittsburgh, PA 15261, USA.
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12
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Ishida H, Nguyen LT, Gopal R, Aizawa T, Vogel HJ. Overexpression of Antimicrobial, Anticancer, and Transmembrane Peptides in Escherichia coli through a Calmodulin-Peptide Fusion System. J Am Chem Soc 2016; 138:11318-26. [DOI: 10.1021/jacs.6b06781] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Hiroaki Ishida
- Biochemistry
Research Group,
Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Leonard T. Nguyen
- Biochemistry
Research Group,
Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Ramamourthy Gopal
- Biochemistry
Research Group,
Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Tomoyasu Aizawa
- Biochemistry
Research Group,
Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Hans J. Vogel
- Biochemistry
Research Group,
Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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13
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Purification of F plasmid-encoded native TraC from Escherichia coli by affinity chromatography on calmodulin Sepharose. Protein Expr Purif 2016; 122:97-104. [PMID: 26892535 DOI: 10.1016/j.pep.2016.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/27/2016] [Accepted: 02/12/2016] [Indexed: 11/21/2022]
Abstract
We have enriched several native bacterial proteins from Escherichia coli by chromatography on the immobilized eukaryotic Ca(2+)-binding protein, calmodulin. These bacterial proteins bound in a Ca(2+)-dependent manner to calmodulin, and were released by the addition of the Ca(2+)-chelator, EGTA, similar to many eukaryotic calmodulin-binding proteins. One of the bacterial proteins, F factor-encoded TraC, was purified to apparent homogeneity by an additional chromatographic step, anion exchange chromatography on MonoQ. Experiments with four chemically distinct calmodulin antagonists (R24571, Compound 48/80, melittin, and W7) showed that all of these substances inhibited the binding of purified TraC to calmodulin at effective concentrations comparable to those required for inhibiting in vitro binding of eukaryotic calmodulin-binding proteins. Three further bacterial proteins were identified as calmodulin-binding proteins: SecA, GlpD, and GlpC. We suggest that also these native bacterial proteins might be isolated by the unusual purification procedure including affinity chromatography on calmodulin Sepharose. Whether the identified proteins bind to, and are regulated by, putative bacterial calmodulin-like proteins in Escherichia coli remains to be established.
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14
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Gómez GE, Monti JLE, Mundo MR, Delfino JM. Solvent Mimicry with Methylene Carbene to Probe Protein Topography. Anal Chem 2015; 87:10080-7. [DOI: 10.1021/acs.analchem.5b02724] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Gabriela Elena Gómez
- Departamento de Química
Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires e Instituto de Química y Fisicoquímica Biológicas (IQUIFIB-CONICET), Junín 956, C1113AAD Buenos Aires, Argentina
| | - José Luis E. Monti
- Departamento de Química
Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires e Instituto de Química y Fisicoquímica Biológicas (IQUIFIB-CONICET), Junín 956, C1113AAD Buenos Aires, Argentina
| | - Mariana Rocío Mundo
- Departamento de Química
Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires e Instituto de Química y Fisicoquímica Biológicas (IQUIFIB-CONICET), Junín 956, C1113AAD Buenos Aires, Argentina
| | - José María Delfino
- Departamento de Química
Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires e Instituto de Química y Fisicoquímica Biológicas (IQUIFIB-CONICET), Junín 956, C1113AAD Buenos Aires, Argentina
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15
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Pastrana-Rios B, Del Valle Sosa L, Santiago J. Trifluoroacetic acid as excipient destabilizes melittin causing the selective aggregation of melittin within the centrin-melittin-trifluoroacetic acid complex. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2015; 2:041711. [PMID: 26798810 PMCID: PMC4711628 DOI: 10.1063/1.4921219] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Accepted: 04/28/2015] [Indexed: 06/05/2023]
Abstract
Trifluoroacetic acid (TFA) may be the cause of the bottleneck in high resolution structure determination for protein-peptide complexes. Fragment based drug design often involves the use of synthetic peptides which contain TFA (excipient). Our goal was to explore the effects of this excipient on a model complex: centrin-melittin-TFA. We performed Fourier transform infrared, two-dimensional infrared correlation spectroscopies and spectral simulations to analyze the amide I'/I'* band for the components and the ternary complex. Melittin (MLT) was observed to have increased helicity upon its interaction with centrin, followed by the thermally induced aggregation of MLT within the ternary complex in the TFA presence.
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Affiliation(s)
| | - Liliana Del Valle Sosa
- Department of Chemistry, University of Puerto Rico , Mayagüez Campus, Call Box 9019, Mayagüez, Puerto Rico 00681, USA
| | - Jorge Santiago
- Department of Chemistry, University of Puerto Rico , Mayagüez Campus, Call Box 9019, Mayagüez, Puerto Rico 00681, USA
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16
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McFadden MJ, Hryciw T, Brown A, Junop MS, Brennan JD. Evaluation of the calmodulin-SOX9 interaction by "magnetic fishing" coupled to mass spectrometry. Chembiochem 2014; 15:2411-9. [PMID: 25233956 DOI: 10.1002/cbic.201402414] [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: 07/27/2014] [Indexed: 11/09/2022]
Abstract
Disruption of calmodulin (CaM)-based protein interactions has been touted as a potential means for modulating several disease pathways. Among these is SOX9, which is a DNA binding protein that is involved in chrondrocyte differentiation and regulation of the hormones that control sexual development. In this work, we employed a "magnetic fishing"/mass spectrometry assay in conjunction with intrinsic fluorescence to examine the interaction of CaM with the CaM-binding domain of SOX9 (SOX-CAL), and to assess the modulation of this interaction by known anti-CaM compounds. Our data show that there is a high affinity interaction between CaM and SOX-CAL (27±9 nM), and that SOX-CAL bound to the same location as the well-known CaM antagonist melittin; unexpectedly, we also found that addition of CaM-binding small molecules initially produced increased SOX-CAL binding, indicative of binding to both the well-known high-affinity CaM binding site and a second, lower-affinity binding site.
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Affiliation(s)
- Meghan J McFadden
- Biointerfaces Institute and Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4M1 (Canada)
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17
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Leclerc E, Leclerc L, Marden MC. Asymmetry of calmodulin revealed by peptide binding. J Fluoresc 2013; 3:45-9. [PMID: 24234718 DOI: 10.1007/bf00865288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/1992] [Revised: 02/05/1993] [Accepted: 02/05/1993] [Indexed: 11/26/2022]
Abstract
The binding of amphiphilic peptides to calmodulin has been studied using fluorescence energy transfer techniques. Calmodulin has no tryptophan residues but possesses two tyrosines (at positions 99 and 138) in the C-terminal half of the protein. The peptides have a single tryptophan which serves as energy acceptor for the protein tyrosine fluorescence. For the binding of mastoparan or peptide Baa17, with a tryptophan at position 3, the observed quenching of the tyrosine fluorescence of over a factor of 2 corresponds to an average tyrosine-trytophan distance of less than 14 Å. These results indicate that the peptides binds preferentially with the tryptophan in the C-terminal half of the protein.
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Affiliation(s)
- E Leclerc
- INSERM U299, Hôpital de Bicêtre, 94275, Le Kremlin Bicêtre, France
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18
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Li H, Wells SA, Jimenez-Roldan JE, Römer RA, Zhao Y, Sadler PJ, O'Connor PB. Protein flexibility is key to cisplatin crosslinking in calmodulin. Protein Sci 2012; 21:1269-79. [PMID: 22733664 PMCID: PMC3631356 DOI: 10.1002/pro.2111] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 06/15/2012] [Indexed: 01/03/2023]
Abstract
Chemical crosslinking in combination with Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) has significant potential for studying protein structures and protein-protein interactions. Previously, cisplatin has been shown to be a crosslinker and crosslinks multiple methionine (Met) residues in apo-calmodulin (apo-CaM). However, the inter-residue distances obtained from nuclear magnetic resonance structures are inconsistent with the measured distance constraints by crosslinking. Met residues lie too far apart to be crosslinked by cisplatin. Here, by combining FTICR MS with a novel computational flexibility analysis, the flexible nature of the CaM structure is found to be key to cisplatin crosslinking in CaM. It is found that the side chains of Met residues can be brought together by flexible motions in both apo-CaM and calcium-bound CaM (Ca₄-CaM). The possibility of cisplatin crosslinking Ca₄-CaM is then confirmed by MS data. Therefore, flexibility analysis as a fast and low-cost computational method can be a useful tool for predicting crosslinking pairs in protein crosslinking analysis and facilitating MS data analysis. Finally, flexibility analysis also indicates that the crosslinking of platinum to pairs of Met residues will effectively close the nonpolar groove and thus will likely interfere with the binding of CaM to its protein targets, as was proved by comparing assays for cisplatin-modified/unmodified CaM binding to melittin. Collectively, these results suggest that cisplatin crosslinking of apo-CaM or Ca₄-CaM can inhibit the ability of CaM to recognize its target proteins, which may have important implications for understanding the mechanism of tumor resistance to platinum anticancer drugs.
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Affiliation(s)
- Huilin Li
- Department of Chemistry, University of WarwickCoventry, CV4 7AL, United Kingdom
| | - Stephen A Wells
- Department of Physics and Centre for Scientific Computing, University of WarwickCoventry, CV4 7AL, United Kingdom
| | - J Emilio Jimenez-Roldan
- Department of Physics and Centre for Scientific Computing, University of WarwickCoventry, CV4 7AL, United Kingdom
| | - Rudolf A Römer
- Department of Physics and Centre for Scientific Computing, University of WarwickCoventry, CV4 7AL, United Kingdom
| | - Yao Zhao
- Department of Chemistry, University of WarwickCoventry, CV4 7AL, United Kingdom
| | - Peter J Sadler
- Department of Chemistry, University of WarwickCoventry, CV4 7AL, United Kingdom
| | - Peter B O'Connor
- Department of Chemistry, University of WarwickCoventry, CV4 7AL, United Kingdom
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19
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Bedard K, Jaquet V, Krause KH. NOX5: from basic biology to signaling and disease. Free Radic Biol Med 2012; 52:725-34. [PMID: 22182486 DOI: 10.1016/j.freeradbiomed.2011.11.023] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 11/10/2011] [Accepted: 11/12/2011] [Indexed: 02/07/2023]
Abstract
In mammals, the NADPH oxidase family of enzymes comprises seven members: NOXs 1-5, DUOX1, and DUOX2. All of these enzymes function to move an electron across cellular membranes, transferring it to oxygen to generate the superoxide anion. This generation of reactive oxygen species has important physiological and pathophysiological roles. NOX5 is perhaps the least well understood of these NOX isoforms, in part because the gene is not present in mice or rats. In recent years, however, there has been a rapid increase in our understanding of the NOX5 gene, the structural and biochemical aspects of the NOX5 enzyme, the role NOX5 plays in health and disease, and the development of novel NOX inhibitors. This review takes a look back at some historical aspects of the discovery of NOX5 and summarizes our current understanding of the enzyme.
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Affiliation(s)
- Karen Bedard
- Department of Pathology, Dalhousie University, Halifax, Canada
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20
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Sperry JB, Huang RYC, Zhu MM, Rempel DL, Gross ML. Hydrophobic Peptides Affect Binding of Calmodulin and Ca as Explored by H/D Amide Exchange and Mass Spectrometry. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2011; 302:85-92. [PMID: 21765646 PMCID: PMC3134286 DOI: 10.1016/j.ijms.2010.08.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Calmodulin (CaM), a ubiquitous intracellular sensor protein, binds Ca(2+) and interacts with various targets as part of signal transduction. Using hydrogen/deuterium exchange (H/DX) and a high resolution PLIMSTEX (Protein-Ligand Interactions by Mass Spectrometry, Titration, and H/D Exchange) protocol, we examined five different states of calmodulin: calcium-free, calcium-loaded, and three states of calcium-loaded in the presence of either melittin, mastoparan, or skeletal myosin light-chain kinase (MLCK). When CaM binds Ca(2+), the extent of HDX decreased, consistent with the protein becoming stabilized upon binding. Furthermore, Ca(2+)-saturated calmodulin exhibits increased protection when bound to the peptides, forming high affinity complexes. The protocol reveals significant changes in EF hands 1, 3, and 4 with saturating levels of Ca(2+). Titration of the protein using PLIMSTEX provides the binding affinity of Ca(2+) to calmodulin within previously reported values. The affinities of calmodulin to Ca(2+) increase by factors of 300 and 1000 in the presence of melittin and mastoparan, respectively. A modified PLIMSTEX protocol whereby the protein is digested to component peptides gives a region-specific titration. The titration data taken in this way show a decrease in the root mean square fit of the residuals, indicating a better fit of the data. The global H/D exchange results and those obtained in a region-specific way provide new insight into the Ca(2+)-binding properties of this well-studied protein.
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Affiliation(s)
- Justin B Sperry
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, POBox 1134, St. Louis, MO 63130
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21
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Chavez JD, Liu NL, Bruce JE. Quantification of protein-protein interactions with chemical cross-linking and mass spectrometry. J Proteome Res 2011; 10:1528-37. [PMID: 21222489 DOI: 10.1021/pr100898e] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Chemical cross-linking in combination with mass spectrometry has largely been used to study protein structures and protein-protein interactions. Typically, it is used in a qualitative manner to identify cross-linked sites and provide a low-resolution topological map of the interacting regions of proteins. Here, we investigate the capability of chemical cross-linking to quantify protein-protein interactions using a model system of calmodulin and substrates melittin and mastoparan. Calmodulin is a well-characterized protein which has many substrates. Melittin and mastoparan are two such substrates which bind to calmodulin in 1:1 ratios in the presence of calcium. Both the calmodulin-melittin and calmodulin-mastoparan complexes have had chemical cross-linking strategies successfully applied in the past to investigate topological properties. We utilized an excess of immobilized calmodulin on agarose beads and formed complexes with varying quantities of mastoparan and melittin. Then, we applied disuccinimidyl suberate (DSS) chemical cross-linker, digested and detected cross-links through an LC-MS analytical method. We identified five interpeptide cross-links for calmodulin-melittin and three interpeptide cross-links for calmodulin-mastoparan. Using cross-linking sites of calmodulin-mastoparan, we demonstrated that mastoparan also binds in two orientations to calmodulin. We quantitatively demonstrated that both melittin and mastoparan preferentially bind to calmodulin in a parallel fashion, which is opposite to the preferred binding mode of the majority of known calmodulin binding peptides. We also demonstrated that the relative abundances of cross-linked peptide products quantitatively reflected the abundances of the calmodulin peptide complexes formed.
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Affiliation(s)
- Juan D Chavez
- Department of Genome Sciences, University of Washington, PO Box 358050, Seattle, Washington 98195, United States
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22
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Wyttenbach T, Grabenauer M, Thalassinos K, Scrivens JH, Bowers MT. The effect of calcium ions and peptide ligands on the relative stabilities of the calmodulin dumbbell and compact structures. J Phys Chem B 2010; 114:437-47. [PMID: 20000583 DOI: 10.1021/jp906242m] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A combination of ion mobility and mass spectrometry methods was used to characterize the molecular shape of the protein calmodulin (CaM) and its complexes with calcium and a number of peptide ligands. CaM, a calcium-binding protein composed of 148 amino acid residues, was found by X-ray crystallography to occur both in a globular shape and in the shape of an extended dumbbell. Here, it was found, as solutions of CaM and CaM complexes were sprayed into the solvent-free environment of the mass spectrometer, that major structural features of the molecule and the stoichiometry of the units constituting a complex in solution were preserved in the desolvation process. Two types of CaM structures were observed in our experiments: a compact and an extended form of CaM with measured cross sections in near-perfect agreement with those calculated for the known globular and extended dumbbell X-ray geometries. Calcium-free solutions yielded predominantly an extended CaM conformation. Ca(n)(2+)-CaM complexes were observed in calcium-containing solutions, n = 0-4, with the population of the compact conformation increasing relative to the elongated conformation as n increases. For n = 4, a predominantly compact globular conformation was observed. Solutions containing the peptide CaMKII(290-309), the CaM target domain of the Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) enzyme, yielded predominantly globular Ca(4)(2+)-CaM-CaMKII(290-309) complexes. Similar results were obtained with the 26-residue peptide melittin. For the 14-residue C-terminal melittin fragment, on the other hand, formation of both a 1:1 and a 1:2 CaM-peptide complex was detected. On the basis of the entirety of our results, we conclude that the collapse of extended (dumbbell-like) CaM structures into more compact globular structures occurs upon specific binding of four calcium ions. Furthermore, this calcium-induced structural collapse of CaM appears to be a prerequisite for formation of a particularly stable CaM-peptide complex involving peptides long enough to be engaged in interactions with both lobes of CaM.
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Affiliation(s)
- Thomas Wyttenbach
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, USA
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23
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Kovacs E, Tóth J, Vértessy BG, Liliom K. Dissociation of calmodulin-target peptide complexes by the lipid mediator sphingosylphosphorylcholine: implications in calcium signaling. J Biol Chem 2009; 285:1799-808. [PMID: 19910470 DOI: 10.1074/jbc.m109.053116] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previously we have identified the lipid mediator sphingosylphosphorylcholine (SPC) as the first potentially endogenous inhibitor of the ubiquitous Ca2+ sensor calmodulin (CaM) (Kovacs, E., and Liliom, K. (2008) Biochem. J. 410, 427-437). Here we give mechanistic insight into CaM inhibition by SPC, based on fluorescence stopped-flow studies with the model CaM-binding domain melittin. We demonstrate that both the peptide and SPC micelles bind to CaM in a rapid and reversible manner with comparable affinities. Furthermore, we present kinetic evidence that both species compete for the same target site on CaM, and thus SPC can be considered as a competitive inhibitor of CaM-target peptide interactions. We also show that SPC disrupts the complex of CaM and the CaM-binding domain of ryanodine receptor type 1, inositol 1,4,5-trisphosphate receptor type 1, and the plasma membrane Ca2+ pump. By interfering with these interactions, thus inhibiting the negative feedback that CaM has on Ca2+ signaling, we hypothesize that SPC could lead to Ca2+ mobilization in vivo. Hence, we suggest that the action of the sphingolipid on CaM might explain the previously recognized phenomenon that SPC liberates Ca2+ from intracellular stores. Moreover, we demonstrate that unlike traditional synthetic CaM inhibitors, SPC disrupts the complex between not only the Ca2+-saturated but also the apo form of the protein and the target peptide, suggesting a completely novel regulation for target proteins that constitutively bind CaM, such as ryanodine receptors.
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Affiliation(s)
- Erika Kovacs
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest H-1113, Hungary.
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24
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Abstract
Potentiation of Bleomycin Lethality in HeLa and V79 Cells by Bee VenomThis study investigated possible growth-inhibiting effects of bee venom applied alone or in combination with a cytotoxic drug bleomycin on HeLa and V79 cells in vitro based on clone formation, cell counting, and apoptosis. Melittin, the key component of bee venom, is a potent inhibitor of calmodulin activity, and also a potent inhibitor cell growth and clonogenicity. Intracellular accumulation of melittin correlates with the cytotoxicity of antitumour agents. Previous studies indicated that some calcium antagonists and calmodulin inhibitors enhanced intracellular levels of antitumor agents by inhibiting their outward transport. In this study, treatment of exponentially growing HeLa and V79 cells with bleomycin caused a dose-dependent decrease in cell survival due to DNA damage. This lethal effect was potentiated by adding a non-lethal dose of the bee venom. By preventing repair of damaged DNA, bee venom inhibited recovery from potentially lethal damage induced by bleomycin in V79 and HeLa cells. Apoptosis, necrosis, and lysis were presumed as possible mechanisms by which bee venom inhibited growth and clonogenicity of V79 cells. HeLa cells, on the other hand, showed greater resistance to bee venom. Our findings suggest that bee venom might find a therapeutic use in enhancing cytotoxicity of antitumour agent bleomycin.
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25
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Wang Z, Yu X, Cui M, Liu Z, Song F, Liu S. Investigation of calmodulin-Peptide interactions using matrix-assisted laser desorption/ionization mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2009; 20:576-583. [PMID: 19110443 DOI: 10.1016/j.jasms.2008.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2008] [Revised: 11/20/2008] [Accepted: 11/20/2008] [Indexed: 05/27/2023]
Abstract
In this report, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was used to study the binding interactions between calmodulin and two target peptides (melittin and substance P). Various matrix conditions were tested and the less acidic matrix DHAP and THAP were found to favor the survival of the intact calcium-calmodulin as well as the calmodulin-peptide complexes. However, the application of direct MALDI-MS to detect the intact complexes turned out to be very difficult due to the dissociation of the complexes and the formation of nonspecific aggregates. In contrast, the specific binding of the target peptides to calmodulin could be easily deduced using intensity-fading (IF) MALDI-MS. Compared with the nonbinding control, clear reduction in the ion abundances of the target peptides was observed with the addition of calmodulin. Relative binding affinities of different peptides towards the protein could also be estimated using IF-MALDI-MS. This study may extend the application of IF-MALDI-MS in the analysis of noncovalent complexes and offer a perspective into the utility of MALDI-MS as an alternative approach to study the peptides binding to calmodulin.
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Affiliation(s)
- Zhaofu Wang
- Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun Center of Mass Spectrometry, Changchun, PR China
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26
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Abstract
S1P (sphingosine 1-phosphate) and SPC (sphingosylphosphorylcholine) have been recently recognized as important mediators of cell signalling, regulating basic cellular processes such as growth,differentiation, apoptosis, motility and Ca2+ homoeostasis.Interestingly, they can also act as first and second messengers. Although their activation of cell-surface G-protein-coupled receptors has been studied extensively, not much is known about heir intracellular mechanism of action, and their target proteins are yet to be identified. We hypothesized that these sphingolipids might bind to CaM (calmodulin), the ubiquitous intracellular Ca2+sensor. Binding assays utilizing intrinsic tyrosine fluorescence of the protein, dansyl-labelled CaM and surface plasmon resonance revealed that SPC binds to both apo- and Ca2+-saturated CaM selectively, when compared with the related lysophospholipid mediators S1P, LPA (lysophosphatidic acid) and LPC (lysophosphatidylcholine). Experiments carried out with the model CaM-binding domain melittin showed that SPC dissociates the CaM-target peptide complex, suggesting an inhibitory role. The functional effect of the interaction was examined on two target enzymes, phosphodiesterase and calcineurin, and SPC inhibited the Ca2+/CaM-dependent activity of both. Thus we propose that CaM might be an intracellular receptor for SPC, and raise the possibility of a novel endogenous regulation of CaM.
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27
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Newman RA, Van Scyoc WS, Sorensen BR, Jaren OR, Shea MA. Interdomain cooperativity of calmodulin bound to melittin preferentially increases calcium affinity of sites I and II. Proteins 2008; 71:1792-812. [DOI: 10.1002/prot.21861] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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28
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Zhao Y, Feng J, Liang A, Yang B. Binding of Euplotes octocarinatus centrin with target peptide melittin. CHINESE SCIENCE BULLETIN-CHINESE 2007. [DOI: 10.1007/s11434-007-0476-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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29
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Mathur S, Badertscher M, Scott M, Zenobi R. Critical evaluation of mass spectrometric measurement of dissociation constants: accuracy and cross-validation against surface plasmon resonance and circular dichroism for the calmodulin–melittin system. Phys Chem Chem Phys 2007; 9:6187-98. [DOI: 10.1039/b707946j] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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30
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Karasawa T, Sugawara M. A surface plasmon resonance sensor for substance P using gold-modified calmodulin and melittin. ANAL SCI 2005; 21:1431-6. [PMID: 16379381 DOI: 10.2116/analsci.21.1431] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A surface plasmon resonance (SPR) biosensor for the quantification of a neuropeptide substance P (SP) is described based on an inhibition assay using Au colloid-modified calmodulin (Au-CaM) and a target peptide melittin immobilized on carboxymethylated dextran. The modification of CaM with streptavidin Au colloids was achieved in a sample solution by the amine coupling method. The SPR signal sharply increased, corresponding to the formation of a Ca2+-Au-CaM-melittin complex on the sensor surface, and approached a steady state within 5 min. When SP was added to a sample solution, the SPR signal was decreased, due to the formation of a Ca2+-Au-CaM-SP complex in the sample solution. The modification of CaM with streptavidin Au colloids was effective for enhancing the SPR signal for SP. A decrease in the SPR signal was observed for SP in the concentration range from 0.10 to 5.0 microM, whose lower limit was ten-times superior to that (1.0 microM) with unmodified CaM. The response was highly selective to SP and the selectivity was in the order of SP >> neurokinin A > neurokinin B > neurotransmitters (glycine, GABA, L-glutamate, acetylcholine, norepinephrine, 5HT) - substance P fragment (1 - 7). The potential use of the present sensor for the quantification of SP in mouse brain extracts is demonstrated.
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Affiliation(s)
- Takanori Karasawa
- Department of Chemistry, College of Humanities and Sciences, Nihon University, Setagaya-ku, Tokyo 156-8550, Japan
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31
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Li H, Aluko RE. Kinetics of the inhibition of calcium/calmodulin-dependent protein kinase II by pea protein-derived peptides. J Nutr Biochem 2005; 16:656-62. [PMID: 16111873 DOI: 10.1016/j.jnutbio.2005.05.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Revised: 01/07/2005] [Accepted: 01/12/2005] [Indexed: 11/22/2022]
Abstract
Calcium/calmodulin-dependent protein kinase II (CaMKII) catalyzes the phosphorylation of various cellular proteins and excessive activities have been implicated in the pathogenesis of various chronic diseases. We hypothesized that positively charged peptides can be produced through enzymatic hydrolysis of pea proteins; such peptides could then bind to negatively charged calmodulin (CaM) at a physiological pH level and inhibit CaMKII activity. Pea protein isolate was hydrolyzed with an alkaline protease (alcalase) and filtered through a 1000-mol wt cutoff membrane. The permeate, which contained low-molecular weight peptides, was used to isolate cationic peptides on an SP-Sepharose column by ion exchange chromatography. Separation of the permeate on the SP-Sepharose column yielded two fractions with net positive charges that were subsequently used for enzyme inhibition studies. Fraction I eluted earlier from the column and contained lower contents of lysine and arginine than Fraction II, which eluted later. Results show that both peptide fractions inhibited CaMKII activity mostly in a competitive manner, although kinetic data suggested that inhibition by Fraction II may be of the mixed type. Kinetic analysis (K(m) and K(i)) showed that affinity of peptides in Fraction II for CaM was more than that in Fraction I, which was directly correlated with the higher inhibitory properties of Fraction II against CaMKII. The results suggest that it may be possible to use pea protein-derived cationic peptides to modulate CaMKII activities.
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Affiliation(s)
- Huan Li
- Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Canada
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32
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Katoh N. Similarities of cow mammary gland cytosolic 21-kDa protein, the substrate for protein kinase C, to the 20-kDa myosin light chain from smooth muscle. J Vet Med Sci 2005; 67:29-34. [PMID: 15699591 DOI: 10.1292/jvms.67.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the cytosol of cow mammary gland, several proteins are phosphorylated in the presence of the protein kinase C (PKC) cofactors 1-oleoyl-2-acetyl-sn-glycerol (OAG), phosphatidylserine (PS) and Ca2+. Of the substrates, the 21-kDa protein is inferred to be a 20-kDa regulatory myosin light chain (MLC20) from smooth muscle because of its molecular mass, its distribution in the cytosol, its association with melittin and sphingosine (the PKC modulators), and phosphorylation by PKC as well as by Ca2+/calmodulin-dependent myosin light chain kinase (MLCK). The present study was undertaken to examine whether the 21-kDa protein could be identified as MLC20, by adding cow uterine MLC20 to the reaction mixture containing cytosol with or without the PKC cofactors and/or calmodulin. In the absence of MLC20, the 21-kDa protein was phosphorylated when the PKC cofactors and calmodulin were added to the reaction mixture. Phosphorylation of the 21-kDa protein was inhibited by melittin or sphingosine, and the inhibition was reversed by PS, but not by calmodulin. When MLC20 was included in the reaction mixture, it was phosphorylated in the presence of the PKC cofactors, and the phosphorylated MLC20 band overlapped that of the 21-kDa protein. The indistinguishably overlapped band of the two proteins was inhibited by melittin and by sphingosine, and their inhibition was reversed by PS, not by calmodulin. It is suggested that the 21-kDa protein is the smooth muscle MLC20 and also that the 21-kDa MLC20 is phosphorylated by PKC, but not by MLCK.
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Affiliation(s)
- Norio Katoh
- National Institute of Animal Health, Kannondai, Tsukuba, Ibaraki, Japan
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33
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Schmidt A, Kalkhof S, Ihling C, Cooper DMF, Sinz A. Mapping protein interfaces by chemical cross-linking and Fourier transform ion cyclotron resonance mass spectrometry: application to a calmodulin / adenylyl cyclase 8 peptide complex. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2005; 11:525-34. [PMID: 16322659 DOI: 10.1255/ejms.748] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Chemical cross-linking--an established technique in protein chemistry--has re-emerged, in combination with mass spectrometric analysis of the reaction products, as a valuable tool to identify interacting amino acid sequences in protein complexes. In the present study, we are mapping the interface of the calcium-dependent complex between calmodulin (CaM) and a peptide derived from the C-terminal region of adenylyl cyclase 8 (AC 8). Cross-linking reactions are performed using the two amine-reactive, isotope-labeled (d0 and d4) cross-linkers BS(3) (bis[sulfosuccinimidyl]suberate) and BS(2)G (bi[sulfosuccinimidyl] glutarate) as well as the 'zero-length' cross-linker (EDC, ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride). After separation of the cross-linking reaction mixtures by one-dimensional gel electrophoresis (sodium dodecyl sulphate polyacrylamide gel) and in-gel digestion of the cross-linked complexes, the resulting peptide mixtures are analyzed by nano-high-performance liquid chromatography/ nano-electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The identified intermolecular cross-linking products will give further insight into calmodulin/adenylyl cyclase 8 interaction.
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Affiliation(s)
- Andreas Schmidt
- Biotechnological-Biomedical Center, Faculty of Chemistry and Mineralogy, University of Leipzig, D-04103 Leipzig, Germany
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34
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Cox JA, Tirone F, Durussel I, Firanescu C, Blouquit Y, Duchambon P, Craescu CT. Calcium and Magnesium Binding to Human Centrin 3 and Interaction with Target Peptides. Biochemistry 2004; 44:840-50. [PMID: 15654740 DOI: 10.1021/bi048294e] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There are four isoforms of centrin in mammals, with variable sequence, tissue expression, and functional properties. We have recently characterized a number of structural, ion, and target binding properties of human centrin isoform HsCen2. This paper reports a similar characterization of HsCen3, overexpressed in Escherichia coli and purified by phase-reversed chromatography. Equilibrium and dynamic binding studies revealed that HsCen3 has one mixed Ca(2+)/Mg(2+) binding site of high affinity (K(d) = 3 and 10 microM for Ca(2+) and Mg(2+), respectively) and two Ca(2+)-specific sites of low affinity (K(d) = 140 microM). The metal-free protein is fragmented by an unidentified protease into a polypeptide segment of 11 kDa, which was purified by HPLC, and identified by mass spectrometry as the segment of residues 21-112. Similarly, controlled trypsinolysis on Ca(2+)-bound HsCen3 yielded a mixture of segments of residues 1-124 and 1-125. The Ca(2+)/Mg(2+) site could be assigned to this segment and thus resides in the N-terminal half of HsCen3. Temperature denaturation experiments, circular dichroism, and utilization of fluorescence hydrophobic probes allowed us to propose that the metal-free protein has molten globule characteristics and that the dication-bound forms are compact with a polar surface for the Mg(2+) form and a hydrophobic exposed surface for the Ca(2+) form. Thus, HsCen3 could be classified as a Ca(2+) sensor protein. In addition, it is able to bind strongly to a model target peptide (melittin), as well as to peptides derived from the protein XPC and Kar1p, with a moderate Ca(2+) dependence.
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Affiliation(s)
- Jos A Cox
- Department of Biochemistry, University of Geneva, Geneva 4, Switzerland
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35
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Schulz DM, Ihling C, Clore GM, Sinz A. Mapping the topology and determination of a low-resolution three-dimensional structure of the calmodulin-melittin complex by chemical cross-linking and high-resolution FTICRMS: direct demonstration of multiple binding modes. Biochemistry 2004; 43:4703-15. [PMID: 15096039 DOI: 10.1021/bi036149f] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Calmodulin serves as a calcium-dependent regulator in many metabolic pathways and is known to bind with high affinity to various target proteins and peptides. One such target is the small peptide melittin, the principal component of honeybee venom. The calmodulin-melittin system was used as a model system to gain further insight into target recognition of calmodulin. Using chemical cross-linking in combination with high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS), we have determined the interacting regions within the calcium-dependent calmodulin-melittin complex and thus the orientation of bound melittin. Using ambiguous distance restraints derived from the chemical cross-linking data in combination with recently developed computational methods of conjoined rigid body/torsion angle simulated annealing, we were able to generate low-resolution three-dimensional structure models of the calmodulin-melittin complex, for which no high-resolution structure exists to date. Our data provide evidence for the first time that calmodulin can recognize target peptides in two opposing orientations simultaneously. The general procedure for mapping interacting regions within the complex involves conjugation of calmodulin and melittin with several cross-linking reagents possessing different specificities and spacer lengths, followed by enzymatic proteolysis of the cross-linked complex. The highly complex peptide mixtures were subsequently analyzed by nano-HPLC, which was online coupled to a FTICR mass spectrometer equipped with a nano-electrospray ionization source. The mass spectra obtained in this manner were screened for possible cross-linking products using customized software programs. This integrated approach, exemplified for mapping the topology of the calmodulin-melittin complex, is likely to have wide-ranging implications for structural studies on protein-protein interactions.
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Affiliation(s)
- Daniela M Schulz
- Biotechnological-Biomedical Center, Faculty of Chemistry and Mineralogy, University of Leipzig, D-04103 Leipzig, Germany
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36
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Bánfi B, Tirone F, Durussel I, Knisz J, Moskwa P, Molnár GZ, Krause KH, Cox JA. Mechanism of Ca2+ Activation of the NADPH Oxidase 5 (NOX5). J Biol Chem 2004; 279:18583-91. [PMID: 14982937 DOI: 10.1074/jbc.m310268200] [Citation(s) in RCA: 300] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
NADPH oxidase 5 (NOX5) is a homologue of the gp91(phox) subunit of the phagocyte NADPH oxidase. NOX5 is expressed in lymphoid organs and testis and distinguished from the other NADPH oxidases by its unique N terminus, which contains three canonical EF-hands, Ca(2+)-binding domains. Upon heterologous expression, NOX5 was shown to generate superoxide in response to intracellular Ca(2+) elevations. In this study, we have analyzed the mechanism of Ca(2+) activation of NOX5. In a cell-free system, Ca(2+) elevations triggered superoxide production by NOX5 (K(m) = 1.06 microm) in an NADPH- and FAD-dependent but cytosol-independent manner. That result indicated a role for the N-terminal EF-hands in NOX5 activation. Therefore, we generated recombinant proteins of NOX5 N terminus and investigated their interactions with Ca(2+). Flow dialysis experiments showed that NOX5 N terminus contained four Ca(2+)-binding sites and allowed us to define the hitherto unidentified fourth, non-canonical EF-hand. The EF-hands of NOX5 formed two pairs: the very N-terminal pair had relatively low affinity for Ca(2+), whereas the more C-terminal pair bound Ca(2+) with high affinity. Ca(2+) binding caused a marked conformation change in the N terminus, which exposed its hydrophobic core, and became able to bind melittin, a model peptide for calmodulin targets. Using a pull-down assay, we demonstrate that the regulatory N terminus and the catalytic C terminus of NOX5 interact in a Ca(2+)-dependent way. Our results indicate that the Ca(2+)-induced conformation change of NOX5 N terminus led to enzyme activation through an intra-molecular interaction. That represents a novel mechanism of activation among NAD(P)H oxidases and Ca(2+)-activated enzymes.
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Affiliation(s)
- Botond Bánfi
- Department of Biochemistry, University of Geneva, CH-1211 Genève, Switzerland
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37
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Shorina EA, Dolgova NV, Rubtsov AM, Storey KB, Lopina OD. Melittin induces both time-dependent aggregation and inhibition of Na,K-ATPase from duck salt glands however these two processes appear to occur independently. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004; 1661:188-95. [PMID: 15003881 DOI: 10.1016/j.bbamem.2004.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Revised: 01/20/2004] [Accepted: 01/21/2004] [Indexed: 11/22/2022]
Abstract
Using cupric phenanthroline as a cross-linking agent, we have shown that melittin induced time-dependent aggregations of Na,K-ATPase in microsomal fractions and in preparations of purified Na,K-ATPase from duck salt glands. Incubation of melittin with these preparations also led to the progressive loss of Na,K-ATPase activity. At melittin/protein molar ratio of 5:1, we did not observe inhibition of Na,K-ATPase in the microsomal fraction but the process of enzyme aggregation occurred. At higher melittin/protein molar ratios (10:1 and 30:1), the inhibition of the enzyme and its aggregation proceeded simultaneously but the rates of these processes and maximal values achieved were different. At a melittin/protein ratio of 30:1, Na,K-ATPase inhibition may be described as a biexponential curve with the values for pseudo-first order rate constants being 2.7 and 0.15 min(-1). However, the aggregation may be presented by a monoexponential curve with a pseudo-first order rate constant of 0.15 min(-1). In purified preparations of Na,K-ATPase, the maximal aggregation (about 90%) was achieved at a melittin/protein molar ratio of 2:1, and a further increase in the melittin/protein ratio increased the rate of aggregation but did not affect the value of maximal aggregation. The results show that melittin induced both aggregation and inhibition of Na,K-ATPase but these two processes proceeded independently.
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Affiliation(s)
- Ekaterina A Shorina
- Department of Biochemistry, School of Biology, M.V. Lomonosov Moscow State University, Moscow 119992, Russian Federation
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38
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Orsolić N, Sver L, Verstovsek S, Terzić S, Basić I. Inhibition of mammary carcinoma cell proliferation in vitro and tumor growth in vivo by bee venom. Toxicon 2003; 41:861-70. [PMID: 12782086 DOI: 10.1016/s0041-0101(03)00045-x] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The possible tumor growth- and metastasis-inhibiting effects of bee venom in mice and in tumor cell cultures were studied. The tumor was a transplantable mammary carcinoma (MCa) of CBA mouse. Intravenous administration of bee venom to mice significantly reduced the number of metastases in the lung. However, subcutaneous administration of bee venom did not reduce the number of lung metastases, indicating that the antitumor effect of the venom could be highly dependent on the route of injection as well as close contact between the components of the venom and the tumor cells, as was shown by in vitro studies on MCa cells. We also observed variations in immunological parameter induced by bee venom. We proposed that bee venom has an indirect mechanism of tumor growth inhibition and promotion of tumor rejection that is based on stimulation of the local cellular immune responses in lymph nodes. Apoptosis, necrosis, and lysis of tumor cells are other possible mechanisms by which bee venom inhibits tumor growth.
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Affiliation(s)
- Nada Orsolić
- Department of Animal Physiology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10 000 Zagreb, Croatia.
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39
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Zhu MM, Rempel DL, Du Z, Gross ML. Quantification of protein-ligand interactions by mass spectrometry, titration, and H/D exchange: PLIMSTEX. J Am Chem Soc 2003; 125:5252-3. [PMID: 12720418 DOI: 10.1021/ja029460d] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein-ligand binding and the concomitant conformational change in the protein are of crucial importance in biophysics and drug design. We report a novel method to quantify protein-ligand interactions in solution by mass spectrometry, titration, and H/D exchange (PLIMSTEX). The approach can determine the conformational change, binding stoichiometry, and affinity in protein-ligand interactions including those that involve small molecules, metal ions, and peptides. Binding constants obtained by PLIMSTEX for four model protein-ligand systems agree with K values measured by conventional methods. At higher protein concentration, the method can be used to determine quickly the binding stoichiometry and possibly the purity of proteins. Taking advantage of concentrating the protein on-column and desalting, we are able to use different concentrations of proteins, buffer systems, salts, and pH in the exchange protocol. High picomole quantities of proteins are sufficient, offering significantly better sensitivity than that of NMR and X-ray crystallography. Automation could make PLIMSTEX a high throughput method for library screening, drug discovery, and proteomics.
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Affiliation(s)
- Mei M Zhu
- Resource for Mass Spectrometry, Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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40
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Matei E, Miron S, Blouquit Y, Duchambon P, Durussel I, Cox JA, Craescu CT. C-terminal half of human centrin 2 behaves like a regulatory EF-hand domain. Biochemistry 2003; 42:1439-50. [PMID: 12578356 DOI: 10.1021/bi0269714] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human centrin 2 (HsCen2) is an EF-hand protein that plays a critical role in the centrosome duplication and separation during cell division. We studied the structural and Ca(2+)-binding properties of two C-terminal fragments of this protein: SC-HsCen2 (T94-Y172), covering two EF-hands, and LC-HsCen2 (M84-Y172), having 10 additional residues. Both fragments are highly disordered in the apo state but become better structured (although not conformationally homogeneous) in the presence of Ca(2+) and depending on the nature of the cations (K(+) or Na(+)) in the buffer. Only the longer C-terminal domain, in the Ca(2+)-saturated state and in the presence of Na(+) ions, was amenable to structure determination by nuclear magnetic resonance. The solution structure of LC-HsCen2 reveals an open two EF-hand structure, similar to the conformation of related Ca(2+)-saturated regulatory domains. Unexpectedly, the N-terminal helix segment (F86-T94) lies over the exposed hydrophobic cavity. This unusual intramolecular interaction increases considerably the Ca(2+) affinity and constitutes a useful model for the target binding.
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Affiliation(s)
- Elena Matei
- INSERM U350 and Institut Curie-Recherche, Centre Universitaire, Bâtiments 110-112, 91405 Orsay, France
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41
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Katoh N. Inhibition by melittin of phosphorylation by protein kinase C of annexin I from cow mammary gland. J Vet Med Sci 2002; 64:779-83. [PMID: 12399601 DOI: 10.1292/jvms.64.779] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Protein kinase C (PKC) is a phosphotransferase activated by diacylglycerols, phospholipids and Ca(2+), that regulates a wide variety of biological functions by phosphorylating multiple protein substrates such as annexin I. Annexin I is a phospholipid/Ca (2+)-binding protein distributed in various tissues, including the mammary gland, and is thought to mediate the anti-inflammatory actions of glucocorticoids by inhibiting phospholipase A(2). Melittin, a phospholipase A(2) activator in bee venom, is known to inhibit PKC activity when lysine-rich histone is used as the substrate. The purpose of the present study was to examine whether phosphorylation by PKC of annexin I from cow mammary gland was inhibited by melittin. Melittin inhibited annexin I phosphorylation by PKC in a dose-dependent manner, and its IC(50) value (concentration causing 50% inhibition) was 0.8 microM. The phosphorylation of annexin I was also inhibited by the amphiphilic polypeptides mastoparan and polymyxin B, and their inhibitory effects were comparable to that of melittin. The surface-inactive polypeptide bacitracin was less effective. The inhibition by melittin was effectively reversed by the excess addition of phosphatidylserine, but not distinctly by 1-oleoyl-2-acetyl-sn-glycerol or Ca(2+), suggesting that melittin inhibited the phosphorylation of annexin I by interacting with phosphatidylserine. The inhibition by melittin of PKC phosphorylation of annexin I seems to be pathophysiologically important, because a melittin-like phospholipase A(2)-stimulatory protein is present in bovine endothelial cells.
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Affiliation(s)
- Norio Katoh
- Hokkaido Research Station, National Institute of Animal Health, Hitsujigaoka, Sapporo, Japan
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42
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Gribenko AV, Guzmán-Casado M, Lopez MM, Makhatadze GI. Conformational and thermodynamic properties of peptide binding to the human S100P protein. Protein Sci 2002; 11:1367-75. [PMID: 12021435 PMCID: PMC2373636 DOI: 10.1110/ps.0202202] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
S100P is a member of the S100 subfamily of calcium-binding proteins that are believed to be associated with various diseases, and in particular deregulation of S100P expression has been documented for prostate and breast cancer. Previously, we characterized the effects of metal binding on the conformational properties of S100P and proposed that S100P could function as a Ca2+ conformational switch. In this study we used fluorescence and CD spectroscopies and isothermal titration calorimetry to characterize the target-recognition properties of S100P using a model peptide, melittin. Based on these experimental data we show that S100P and melittin can interact in a Ca2+-dependent and -independent manner. Ca2+-independent binding occurs with low affinity (Kd approximately 0.2 mM), has a stoichiometry of four melittin molecules per S100P dimer and is presumably driven by favorable electrostatic interactions between the acidic protein and the basic peptide. In contrast, Ca2+-dependent binding of melittin to S100P occurs with high affinity (Kd approximately 5 microM) has a stoichiometry of two molecules of melittin per S100P dimer, appears to have positive cooperativity, and is driven by hydrophobic interactions. Furthermore, Ca2+-dependent S100P-melittin complex formation is accompanied by significant conformational changes: Melittin, otherwise unstructured in solution, adopts a helical conformation upon interaction with Ca2+-S100P. These results support a model for the Ca2+-dependent conformational switch in S100P for functional target recognition.
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Affiliation(s)
- Alexey V Gribenko
- Department of Biochemistry and Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, USA
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43
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Durussel I, Méhul B, Bernard D, Schmidt R, Cox JA. Cation- and peptide-binding properties of human calmodulin-like skin protein. Biochemistry 2002; 41:5439-48. [PMID: 11969404 DOI: 10.1021/bi016062z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Human CLSP, a new Ca(2+)-binding protein specifically expressed in differentiated keratinocytes, is a 15.9 kDa, four EF-hand containing protein with 52% sequence identity to calmodulin (CaM). The protein binds four Ca(2+) ions at two pairs of sites with [Ca(2+)](0.5) values of 1.2 and 150 microM, respectively. Mg(2+) at millimolar concentrations strongly decreases the affinity for Ca(2+) of the two high-affinity sites, but has no effect on the low-affinity sites. The protein can also bind two Mg(2+) ([Mg(2+)](0.5) = 57 microM) at the sites of high Ca(2+) affinity. Thus, as fast skeletal muscle troponin C (TnC), CLSP possesses two high-affinity Ca(2+)-Mg(2+) mixed sites and two low-affinity Ca(2+)-specific sites. Studies on the isolated recombinant N- (N-CLSP) and C-terminal half domains of CLSP (C-CLSP) revealed that, in contrast to the case of TNC, the high-affinity Ca(2+)-Mg(2+) mixed sites reside in the N-terminal half. The binding of cations modifies the intrinsic fluorescence of the two Tyr residues. Upon Ca(2+) binding, hydrophobicity is exposed at the protein surface that can be monitored with a fluorescent probe. The Ca(2+)-dependency of the two conformational changes is biphasic in the absence of Mg(2+), but monophasic in the presence of 2 mM Mg(2+), both corresponding closely to direct binding of Ca(2+) to CLSP. In the presence of Ca(2+), human CLSP forms a high-affinity 1:1 complex with melittin, a natural peptide considered to be a model for the interaction of CaM with its targets. In the complex, CLSP binds Ca(2+) with high affinity to all four binding sites. Isolated N- and C-CLSP show only a weak interaction with melittin, which is enhanced when both halves are simultaneously presented to the model peptide.
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Affiliation(s)
- Isabelle Durussel
- Department of Biochemistry, University of Geneva, 1211 Genève, Switzerland
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44
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Calcium-dependent hydrophobic interaction chromatography of calmodulin, troponin C and their proteolytic fragments. FEBS Lett 2001. [DOI: 10.1016/0014-5793(83)80554-7] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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45
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Sorensen BR, Eppel JT, Shea MA. Paramecium calmodulin mutants defective in ion channel regulation associate with melittin in the absence of calcium but require it for tertiary collapse. Biochemistry 2001; 40:896-903. [PMID: 11170410 DOI: 10.1021/bi0023091] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Calmodulin (CaM) is a small acidic protein essential to calcium-mediated signal transduction. Conformational change driven by calcium binding controls its selective activation of myriad target proteins. In most well characterized cases, both homologous domains of CaM interact with a target protein. However, physiologically separable roles for the two domains were demonstrated by mutants of Paramecium tetraurelia [Kung, C. et al. (1992) Cell Calcium 13, 413], some of which have altered calcium affinities [Jaren, O. R. et al. (2000) Biochemistry 39, 6881]. To determine whether these mutants can associate with canonical targets in a calcium-dependent manner, their ability to bind melittin was assessed using analytical gel permeation chromatography, analytical ultracentrifugation, and fluorescence spectroscopy. The Stokes radius of wild-type PCaM and 11 of the mutants decreased dramatically upon binding melittin in the presence of calcium. Fluorescence spectra and sedimentation velocity studies showed that melittin bound to wild-type PCaM and mutants in a calcium-independent manner. However, there were domain-specific perturbations. Mutations in the N-domain of PCaM did not affect the spectrum of melittin (residue W19) under apo or calcium-saturated conditions, whereas most of the mutations in the C-domain did. These data are consistent with a calcium-dependent model of sequential target association whereby melittin (i) binds to the C-domain of PCaM in the absence of calcium, (ii) remains associated with the C-domain upon calcium binding to sites III and IV, and (iii) subsequently binds to the N-domain upon calcium binding to sites I and II of CaM, causing tertiary collapse.
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Affiliation(s)
- B R Sorensen
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, Iowa 52242-1109, USA
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46
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Durussel I, Blouquit Y, Middendorp S, Craescu CT, Cox JA. Cation- and peptide-binding properties of human centrin 2. FEBS Lett 2000; 472:208-12. [PMID: 10788612 DOI: 10.1016/s0014-5793(00)01452-6] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Centrin and calmodulin (CaM) are closely related four-EF-hand Ca(2+)-binding proteins. While CaM is monomeric, centrin 2 is dimeric and binds only two Ca(2+) per dimer, likely to site IV in each monomer. Ca(2+) binding to centrin 2 displays pronounced negative cooperativity and a [Ca(2+)](0.5) of 30 microM. As in CaM, Ca(2+) binding leads to the exposure of a hydrophobic probe-accessible patch on the surface of centrin 2. Provided Ca(2+) is present, centrin 2 forms a 1:1 peptide:monomer complex with melittin with an affinity of 100 nM. The complex binds four instead of two Ca(2+). Our data point to surprising differences in the mode of activation of these homologous proteins.
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Affiliation(s)
- I Durussel
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
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47
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Mori M, Konno T, Ozawa T, Murata M, Imoto K, Nagayama K. Novel interaction of the voltage-dependent sodium channel (VDSC) with calmodulin: does VDSC acquire calmodulin-mediated Ca2+-sensitivity? Biochemistry 2000; 39:1316-23. [PMID: 10684611 DOI: 10.1021/bi9912600] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The voltage-dependent sodium channel (VDSC) interacts with intracellular molecules to modulate channel properties and localizations in neuronal cells. To study protein interactions, we applied yeast two-hybrid screening to the cytoplasmic C-terminal domain of the main pore-forming alpha-subunit. We found a novel interaction between the C-terminal domain and calmodulin (CaM). By two-hybrid interaction assays, we specified the interaction site of VDSC in a C-terminal region, which is composed of 38 amino acid residues and contains both IQ-like and Baa motifs. Using a fusion protein of the C-terminal domain, we showed that interaction with CaM occurred in the presence and absence of Ca(2+). Two synthetic peptides, each covering the IQ-like (NaIQ) or the Baa motifs (NaBaa), were used to examine the binding property by a gel mobility shift assay. Although the NaIQ and NaBaa sequences are overlapped, NaBaa binds only to Ca(2+)-bound Ca(2+)CaM, whereas NaIQ binds to both Ca(2+)CaM and Ca(2+)-free apoCaM. Fluorescence spectroscopy of dansylated CaM showed Ca(2+)-dependent spectral changes not only for NaBaa.CaM but also for NaIQ.CaM. The results, taken together with other results, indicate that whereas the NaBaa.CaM complex is formed in a Ca(2+)-dependent manner, the NaIQ.CaM complex has two conformational states, distinct with respect to the peptide binding site and the CaM conformation, depending on the Ca(2+) concentration. These observations suggest the possibility that VDSC is functionally modulated through the direct CaM interaction and the Ca(2+)-dependent conformational transition of the complex.
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Affiliation(s)
- M Mori
- Department of Physiological Sciences, The Graduate University for Advanced Studies, National Institue for Physiological Sciences, Okazaki, Japan
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48
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Blondelle SE, Crooks E, Aligué R, Agell N, Bachs O, Esteve V, Tejero R, Celda B, Pastor MT, Pérez-Payá E. Novel, potent calmodulin antagonists derived from an all-D hexapeptide combinatorial library that inhibit in vivo cell proliferation: activity and structural characterization. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2000; 55:148-62. [PMID: 10784031 DOI: 10.1034/j.1399-3011.2000.00162.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Calmodulin is known to bind to various amphipathic helical peptide sequences, and the calmodulin-peptide binding surface has been shown to be remarkably tolerant sterically. D-Amino acid peptides, therefore, represent potential nonhydrolysable intracellular antagonists of calmodulin. In the present study, synthetic combinatorial libraries have been used to develop novel D-amino acid hexapeptide antagonists to calmodulin-regulated phosphodiesterase activity. Five hexapeptides were identified from a library containing over 52 million sequences. These peptides inhibited cell proliferation both in cell culture using normal rat kidney cells and by injection via the femoral vein following partial hepatectomy of rat liver cells. These hexapeptides showed no toxic effect on the cells. Despite their short length, the identified hexapeptides appear to adopt a partial helical conformation similar to other known calmodulin-binding peptides, as shown by CD spectroscopy in the presence of calmodulin and NMR spectroscopy in DMSO. The present peptides are the shortest peptide calmodulin antagonists reported to date showing potential in vivo activity.
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Affiliation(s)
- S E Blondelle
- Torrey Pines Institute for Molecular Studies, San Diego, CA 92121, USA.
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49
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Seeber F. An enzyme-release assay for the assessment of the lytic activities of complement or antimicrobial peptides on extracellular Toxoplasma gondii. J Microbiol Methods 2000; 39:189-96. [PMID: 10670765 DOI: 10.1016/s0167-7012(99)00117-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A method is described which allows the evaluation of the membrane lytic activity of either complement or antimicrobial peptides against the extracellular stage of the human protozoan parasite Toxoplasma gondii. The assay is based on lacZ transgenic parasites, determining the activity of released cytoplasmic beta-galactosidase into the culture supernatant upon membrane disintegration. This method was used to evaluate the lytic activities of (i) complement which is a natural defense mechanism in infected hosts against extracellular parasites, and (ii) antimicrobial peptides which have not been evaluated against T. gondii before. The results show that the assay provides a simple and convenient way to assess the membrane lytic activity of such compounds and that T. gondii, like other protozoan parasites, is vulnerable to the membrane-lytic effect of antimicrobial peptides.
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Affiliation(s)
- F Seeber
- FB Biologie/Parasitologie, Philipps-Universität Marburg, Germany.
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50
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Weljie AM, Vogel HJ. Tryptophan fluorescence of calmodulin binding domain peptides interacting with calmodulin containing unnatural methionine analogues. PROTEIN ENGINEERING 2000; 13:59-66. [PMID: 10679531 DOI: 10.1093/protein/13.1.59] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The interactions between the abundant methionine residues of the calcium regulatory protein calmodulin (CaM) and several of its binding targets were probed using fluorescence spectroscopy. Tryptophan steady-state fluorescence from peptides encompassing the CaM-binding domains of the target proteins myosin light chain kinase (MLCK), cyclic nucleotide phosphodiesterase (PDE) and caldesmon site A and B (CaD A, CaD B), and the model peptide melittin showed Ca(2+)-dependent blue-shifts in their maximum emission wavelength when complexed with wild-type CaM. Blue-shifts were also observed for complexes in which the CaM methionine residues were replaced by selenomethionine, norleucine and ethionine, and when a quadruple methionine to leucine C-terminal mutant of CaM was studied. Quenching of the tryptophan fluorescence intensity was observed with selenomethionine, but not with norleucine or ethionine substituted protein. Fluorescence quenching studies with added potassium iodide (KI) demonstrate that the non-native proteins limit the solvent accessibility of the Trp in the MLCK peptide to levels close to that of the wild-type CaM-MLCK interaction. Our results show that the methionine residues from CaM are highly sensitive to the target peptide in question, confirming the importance of their role in binding interactions. In addition, we provide evidence that the nature of binding in the CaM-CaD B complex is unique compared with the other complexes studied, as the Trp residue of this peptide remains partially solvent exposed upon binding to CaM.
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Affiliation(s)
- A M Weljie
- Department of Biological Sciences, University of Calgary,2500 University Drive NW, Calgary, T2N 1N4, Canada
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