1
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Mast DH, Checco JW, Sweedler JV. Advancing d-amino acid-containing peptide discovery in the metazoan. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1869:140553. [PMID: 33002629 DOI: 10.1016/j.bbapap.2020.140553] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 09/01/2020] [Accepted: 09/25/2020] [Indexed: 12/12/2022]
Abstract
The discovery of enzyme-derived d-amino acid-containing peptides (DAACPs) that have physiological importance in the metazoan challenges previous assumptions about the homochirality of animal proteins while simultaneously revealing new analytical challenges in the structural and functional characterization of peptides. Most known DAACPs have been identified though laborious activity-guided purification studies or by homology to previously identified DAACPs. Peptide characterization experiments are increasingly dominated by high throughput mass spectrometry-based peptidomics, with stereochemistry rarely considered due to the technical challenges of identifying l/d isomerization. This review discusses the prevalence of enzyme-derived DAACPs among animals and the physiological consequences of peptide isomerization. Also highlighted are the analytical methods that have been applied for structural characterization/discovery of DAACPs, including results of several recent studies using non-targeted discovery methods for revealing novel DAACPs, strongly suggesting that more DAACPs remain to be uncovered.
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Affiliation(s)
- David H Mast
- Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - James W Checco
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, United States.
| | - Jonathan V Sweedler
- Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
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2
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Arthropod venoms: Biochemistry, ecology and evolution. Toxicon 2018; 158:84-103. [PMID: 30529476 DOI: 10.1016/j.toxicon.2018.11.433] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 11/20/2018] [Accepted: 11/26/2018] [Indexed: 12/17/2022]
Abstract
Comprising of over a million described species of highly diverse invertebrates, Arthropoda is amongst the most successful animal lineages to have colonized aerial, terrestrial, and aquatic domains. Venom, one of the many fascinating traits to have evolved in various members of this phylum, has underpinned their adaptation to diverse habitats. Over millions of years of evolution, arthropods have evolved ingenious ways of delivering venom in their targets for self-defence and predation. The morphological diversity of venom delivery apparatus in arthropods is astounding, and includes extensively modified pedipalps, tail (telson), mouth parts (hypostome), fangs, appendages (maxillulae), proboscis, ovipositor (stinger), and hair (urticating bristles). Recent investigations have also unravelled an astonishing venom biocomplexity with molecular scaffolds being recruited from a multitude of protein families. Venoms are a remarkable bioresource for discovering lead compounds in targeted therapeutics. Several components with prospective applications in the development of advanced lifesaving drugs and environment friendly bio-insecticides have been discovered from arthropod venoms. Despite these fascinating features, the composition, bioactivity, and molecular evolution of venom in several arthropod lineages remains largely understudied. This review highlights the prevalence of venom, its mode of toxic action, and the evolutionary dynamics of venom in Arthropoda, the most speciose phylum in the animal kingdom.
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3
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Effect of triphenylphosphonium moiety on spatial structure and biointeractions of stereochemical variants of YRFK motif. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2018; 48:25-34. [PMID: 30105402 DOI: 10.1007/s00249-018-1327-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/24/2018] [Accepted: 08/06/2018] [Indexed: 12/30/2022]
Abstract
Chemical modification of therapeutic peptides is an important approach to improving their physicochemical and pharmacokinetic properties. The triphenylphosphonium (TPP) cation has proved to be a powerful modifier; however, its effects on peptide structure and activity remain uncharacterized. In this study, cytoprotective tetrapeptides based on the YRFK opioid motif with L- or D-Arg residues were linked to (triphenylphosphonio)carboxylic acids with ethylene and pentylene spacers (TPP-3 and TPP-6 groups, respectively). The three-dimensional structure of the oligopeptides was analyzed by NMR spectroscopy, computational methods and circular dichroism (CD). A more compact and bent structure with segregated aromatic groups was revealed for the D-arginine-containing tetrapeptide and its TPP-6 derivative. The TPP moiety caused structure-organizing effect on the tetrapeptides, resulting in transition from random coil to β-sheet structures, and decreased the peptide backbone flexibility up to ten times. The TPP-3-modified oligopeptide with the lowest RMSD value (ca. 0.05 Å) was characterized by intrapeptide hydrophobic interactions between the TPP and side groups of Tyr and Phe residues accompanied by strong CD induction. The TPP-6-modified oligopeptides showed enhanced ability to form intermolecular associates and disturb liposomal membranes. The relationship between the spatial structure of the oligopeptides and some of their biologically relevant interactions were additionally revealed and are discussed.
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4
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Aliashkevich A, Alvarez L, Cava F. New Insights Into the Mechanisms and Biological Roles of D-Amino Acids in Complex Eco-Systems. Front Microbiol 2018; 9:683. [PMID: 29681896 PMCID: PMC5898190 DOI: 10.3389/fmicb.2018.00683] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 03/22/2018] [Indexed: 01/22/2023] Open
Abstract
In the environment bacteria share their habitat with a great diversity of organisms, from microbes to humans, animals and plants. In these complex communities, the production of extracellular effectors is a common strategy to control the biodiversity by interfering with the growth and/or viability of nearby microbes. One of such effectors relies on the production and release of extracellular D-amino acids which regulate diverse cellular processes such as cell wall biogenesis, biofilm integrity, and spore germination. Non-canonical D-amino acids are mainly produced by broad spectrum racemases (Bsr). Bsr’s promiscuity allows it to generate high concentrations of D-amino acids in environments with variable compositions of L-amino acids. However, it was not clear until recent whether these molecules exhibit divergent functions. Here we review the distinctive biological roles of D-amino acids, their mechanisms of action and their modulatory properties of the biodiversity of complex eco-systems.
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Affiliation(s)
- Alena Aliashkevich
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Laura Alvarez
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Felipe Cava
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden
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5
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Müller MM. Post-Translational Modifications of Protein Backbones: Unique Functions, Mechanisms, and Challenges. Biochemistry 2017; 57:177-185. [PMID: 29064683 PMCID: PMC5770884 DOI: 10.1021/acs.biochem.7b00861] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
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Post-translational
modifications (PTMs) dramatically enhance the
capabilities of proteins. They introduce new functionalities and dynamically
control protein activity by modulating intra- and intermolecular interactions.
Traditionally, PTMs have been considered as reversible attachments
to nucleophilic functional groups on amino acid side chains, whereas
the polypeptide backbone is often thought to be inert. This paradigm
is shifting as chemically and functionally diverse alterations of
the protein backbone are discovered. Importantly, backbone PTMs can
control protein structure and function just as side chain modifications
do and operate through unique mechanisms to achieve these features.
In this Perspective, I outline the various types of protein backbone
modifications discovered so far and highlight their contributions
to biology as well as the challenges in studying this versatile yet
poorly characterized class of PTMs.
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Affiliation(s)
- Manuel M Müller
- Department of Chemistry, King's College London , 7 Trinity Street, London SE1 1DB, United Kingdom
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6
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Roles of d-Amino Acids on the Bioactivity of Host Defense Peptides. Int J Mol Sci 2016; 17:ijms17071023. [PMID: 27376281 PMCID: PMC4964399 DOI: 10.3390/ijms17071023] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 06/20/2016] [Accepted: 06/21/2016] [Indexed: 12/15/2022] Open
Abstract
Host defense peptides (HDPs) are positively-charged and amphipathic components of the innate immune system that have demonstrated great potential to become the next generation of broad spectrum therapeutic agents effective against a vast array of pathogens and tumor. As such, many approaches have been taken to improve the therapeutic efficacy of HDPs. Amongst these methods, the incorporation of d-amino acids (d-AA) is an approach that has demonstrated consistent success in improving HDPs. Although, virtually all HDP review articles briefly mentioned about the role of d-AA, however it is rather surprising that no systematic review specifically dedicated to this topic exists. Given the impact that d-AA incorporation has on HDPs, this review aims to fill that void with a systematic discussion of the impact of d-AA on HDPs.
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7
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Koehbach J, Gruber CW, Becker C, Kreil DP, Jilek A. MALDI TOF/TOF-Based Approach for the Identification of d- Amino Acids in Biologically Active Peptides and Proteins. J Proteome Res 2016; 15:1487-96. [PMID: 26985971 PMCID: PMC4861975 DOI: 10.1021/acs.jproteome.5b01067] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
Several
biologically active peptides contain a d- amino
acid in a well-defined position, which is position 2 in all peptide
epimers isolated to date from vertebrates and also some from invertebrates.
The detection of such D- residues by standard analytical
techniques is challenging. In tandem mass spectrometric (MS) analysis,
although fragment masses are the same for all stereoisomers, peak
intensities are known to depend on chirality. Here, we observe that
the effect of a d- amino acid in the second N-terminal position
on the fragmentation pattern in matrix assisted laser desorption time-of-flight
spectrometry (MALDI-TOF/TOF MS) strongly depends on the peptide sequence.
Stereosensitive fragmentation (SF) is correlated to a neighborhood
effect, but the d- residue also exerts an overall effect
influencing distant bonds. In a fingerprint analysis, multiple peaks
can thus serve to identify the chirality of a sample in short time
and potentially high throughput. Problematic variations between individual
spots could be successfully suppressed by cospotting deuterated analogues
of the epimers. By identifying the [d-Leu2] isomer of the
predicted peptide GH-2 (gene derived bombininH) in skin secretions
of the toad Bombina orientalis, we
demonstrated the analytical power of SF-MALDI-TOF/TOF measurements.
In conclusion, SF-MALDI-TOF/TOF MS combines high sensitivity, versatility,
and the ability to complement other methods.
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Affiliation(s)
- Johannes Koehbach
- Centre for Physiology and Pharmacology, Medical University of Vienna , Schwarzspanierstraße 17, A-1090 Vienna, Austria.,School of Biomedical Sciences, The University of Queensland , Brisbane, QLD, 4072 Australia
| | - Christian W Gruber
- Centre for Physiology and Pharmacology, Medical University of Vienna , Schwarzspanierstraße 17, A-1090 Vienna, Austria
| | - Christian Becker
- Institute of Biological Chemistry, Department of Chemistry, University of Vienna , Währinger Straße 38, A-1090 Vienna, Austria
| | - David P Kreil
- Chair of Bioinformatics, University of Natural Resources and Life Sciences , Muthgasse 18, A-1190 Vienna, Austria
| | - Alexander Jilek
- Institute of Biological Chemistry, Department of Chemistry, University of Vienna , Währinger Straße 38, A-1090 Vienna, Austria.,Chair of Bioinformatics, University of Natural Resources and Life Sciences , Muthgasse 18, A-1190 Vienna, Austria
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8
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Ollivaux C, Soyez D, Toullec JY. Biogenesis of d
-amino acid containing peptides/proteins: where, when and how? J Pept Sci 2014; 20:595-612. [DOI: 10.1002/psc.2637] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 03/13/2014] [Accepted: 03/18/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Céline Ollivaux
- Sorbonne Universités, UPMC Univ Paris 06, UMR 8227; Integrative Biology of Marine Models, Station Biologique de Roscoff; CS 90074, F-29688 Roscoff cedex France
- CNRS, UMR 8227; Integrative Biology of Marine Models, Station Biologique de Roscoff; CS 90074, F-29688 Roscoff cedex France
| | - Daniel Soyez
- Sorbonne Universités, UPMC Univ Paris 06, ER3; Biogenèse des signaux peptidiques; 7 Quai Saint Bernard F-75251 Paris cedex 05 France
- CNRS, ER3; Biogenèse des signaux peptidiques; 7 Quai Saint Bernard F-75251 Paris cedex 05 France
| | - Jean-Yves Toullec
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7144; Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff; CS 90074, F-29688 Roscoff cedex France
- CNRS, UMR 7144; Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff; CS 90074, F-29688 Roscoff cedex France
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9
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Whittington CM, Belov K. Tracing monotreme venom evolution in the genomics era. Toxins (Basel) 2014; 6:1260-73. [PMID: 24699339 PMCID: PMC4014732 DOI: 10.3390/toxins6041260] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/17/2014] [Accepted: 03/27/2014] [Indexed: 01/07/2023] Open
Abstract
The monotremes (platypuses and echidnas) represent one of only four extant venomous mammalian lineages. Until recently, monotreme venom was poorly understood. However, the availability of the platypus genome and increasingly sophisticated genomic tools has allowed us to characterize platypus toxins, and provides a means of reconstructing the evolutionary history of monotreme venom. Here we review the physiology of platypus and echidna crural (venom) systems as well as pharmacological and genomic studies of monotreme toxins. Further, we synthesize current ideas about the evolution of the venom system, which in the platypus is likely to have been retained from a venomous ancestor, whilst being lost in the echidnas. We also outline several research directions and outstanding questions that would be productive to address in future research. An improved characterization of mammalian venoms will not only yield new toxins with potential therapeutic uses, but will also aid in our understanding of the way that this unusual trait evolves.
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Affiliation(s)
- Camilla M Whittington
- School of Biological Sciences, The University of Sydney, Camperdown, NSW 2006, Australia.
| | - Katherine Belov
- Faculty of Veterinary Science, The University of Sydney, Camperdown, NSW 2006, Australia.
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10
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Structure and antimicrobial activity of platypus 'intermediate' defensin-like peptide. FEBS Lett 2014; 588:1821-6. [PMID: 24694388 DOI: 10.1016/j.febslet.2014.03.044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/12/2014] [Accepted: 03/23/2014] [Indexed: 11/23/2022]
Abstract
The three-dimensional structure of a chemically synthesized peptide that we have called 'intermediate' defensin-like peptide (Int-DLP), from the platypus genome, was determined by nuclear magnetic resonance (NMR) spectroscopy; and its antimicrobial activity was investigated. The overall structural fold of Int-DLP was similar to that of the DLPs and β-defensins, however the presence of a third antiparallel β-strand makes its structure more similar to the β-defensins than the DLPs. Int-DLP displayed potent antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. The four arginine residues at the N-terminus of Int-DLP did not affect the overall fold, but were important for its antimicrobial potency.
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11
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Bai L, Livnat I, Romanova EV, Alexeeva V, Yau PM, Vilim FS, Weiss KR, Jing J, Sweedler JV. Characterization of GdFFD, a D-amino acid-containing neuropeptide that functions as an extrinsic modulator of the Aplysia feeding circuit. J Biol Chem 2013; 288:32837-51. [PMID: 24078634 DOI: 10.1074/jbc.m113.486670] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During eukaryotic translation, peptides/proteins are created using L-amino acids. However, a D-amino acid-containing peptide (DAACP) can be produced through post-translational modification via an isomerase enzyme. General approaches to identify novel DAACPs and investigate their function, particularly in specific neural circuits, are lacking. This is primarily due to the difficulty in characterizing this modification and due to the limited information on neural circuits in most species. We describe a multipronged approach to overcome these limitations using the sea slug Aplysia californica. Based on bioinformatics and homology to known DAACPs in the land snail Achatina fulica, we targeted two predicted peptides in Aplysia, GFFD, similar to achatin-I (GdFAD versus GFAD, where dF stands for D-phenylalanine), and YAEFLa, identical to fulyal (YdAEFLa versus YAEFLa), using stereoselective analytical methods, i.e. MALDI MS fragmentation analysis and LC-MS/MS. Although YAEFLa in Aplysia was detected only in an all L-form, we found that both GFFD and GdFFD were present in the Aplysia CNS. In situ hybridization and immunolabeling of GFFD/GdFFD-positive neurons and fibers suggested that GFFD/GdFFD might act as an extrinsic modulator of the feeding circuit. Consistent with this hypothesis, we found that GdFFD induced robust activity in the feeding circuit and elicited egestive motor patterns. In contrast, the peptide consisting of all L-amino acids, GFFD, was not bioactive. Our data indicate that the modification of an L-amino acid-containing neuropeptide to a DAACP is essential for peptide bioactivity in a motor circuit, and thus it provides a functional significance to this modification.
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Affiliation(s)
- Lu Bai
- From the Beckman Institute for Advanced Science and Technology and Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
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12
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‘Chiral compartmentation’ in metabolism: Enzyme stereo-specificity yielding evolutionary options. FEBS Lett 2013; 587:2790-7. [DOI: 10.1016/j.febslet.2013.05.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 05/04/2013] [Accepted: 05/06/2013] [Indexed: 10/26/2022]
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13
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Morishita F, Furukawa Y, Matsushima O. Molecular cloning of two distinct precursor genes of NdWFamide, a d-tryptophan-containing neuropeptide of the sea hare, Aplysia kurodai. Peptides 2012; 38:291-301. [PMID: 23000476 DOI: 10.1016/j.peptides.2012.08.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 08/22/2012] [Accepted: 08/22/2012] [Indexed: 10/27/2022]
Abstract
NdWFamide (NdWFa) is a D-tryptophan-containing cardioexcitatory neuropeptide in gastropod mollusks, such as Aplysia kurodai and Lymanea stagnalis. In this study, we have cloned two cDNA encoding distinct precursors for NdWFa from the abdominal ganglion of A. kurodai. One of the predicted precursor proteins consisted of 90 amino acids (NWF90), and the other consisted of 87 amino acids (NWF87). Both of the predicted precursor proteins have one NWFGKR sequence preceded by the N-terminal signal peptide. Sequential double staining by in situ hybridization (ISH) and immunostaining with anti-NdWFa antibody suggested that NdWFa-precursor and NdWFa peptide co-exist in neurons located in the right-upper quadrant region of the abdominal ganglion. In ISH, NWF90-specific signal and NWF87-specific one were found in different subsets of neurons in the abdominal ganglia of Aplysia. The expression level of NWF90 gene estimated by RT-PCR is much higher than that of NWF87 gene. These results suggest that NWF90 precursor is the major source of NdWFa in Aplysia ganglia.
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Affiliation(s)
- Fumihiro Morishita
- Department of Biological Science, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
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14
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Kita M. Bioorganic Studies on the Key Natural Products from Venomous Mammals and Marine Invertebrates. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2012. [DOI: 10.1246/bcsj.20120198] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Masaki Kita
- Division of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba
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15
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Detection of platypus-type l/d-peptide isomerase activity in aqueous extracts of papaya fruit. Biotechnol Lett 2012; 34:1659-65. [DOI: 10.1007/s10529-012-0941-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 04/25/2012] [Indexed: 10/28/2022]
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16
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Ligabue-Braun R, Verli H, Carlini CR. Venomous mammals: a review. Toxicon 2012; 59:680-95. [PMID: 22410495 DOI: 10.1016/j.toxicon.2012.02.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 01/19/2012] [Accepted: 02/21/2012] [Indexed: 01/09/2023]
Abstract
The occurrence of venom in mammals has long been considered of minor importance, but recent fossil discoveries and advances in experimental techniques have cast new light into this subject. Mammalian venoms form a heterogeneous group having different compositions and modes of action and are present in three classes of mammals, Insectivora, Monotremata, and Chiroptera. A fourth order, Primates, is proposed to have venomous representatives. In this review we highlight recent advances in the field while summarizing biochemical characteristics of these secretions and their effects upon humans and other animals. Historical aspects of venom discovery and evolutionary hypothesis regarding their origin are also discussed.
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Affiliation(s)
- Rodrigo Ligabue-Braun
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Department of Biophysics-IB, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
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17
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Gehmayr V, Mollay C, Reith L, Müller N, Jilek A. Tight binding of transition-state analogues to a peptidyl-aminoacyl-L/D-isomerase from frog skin. Chembiochem 2011; 12:1996-2000. [PMID: 21739559 PMCID: PMC3195878 DOI: 10.1002/cbic.201100203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Indexed: 11/30/2022]
Affiliation(s)
- Verena Gehmayr
- Institute of Organic Chemistry, Johannes Kepler University LinzAltenberger Strasse 69, 4040 Linz (Austria)
| | - Christa Mollay
- Institute of Molecular Biology, Austrian Academy of SciencesBillrothstrasse 11, 5020 Salzburg (Austria)
| | - Lorenz Reith
- Institute of Organic Chemistry, Johannes Kepler University LinzAltenberger Strasse 69, 4040 Linz (Austria)
| | - Norbert Müller
- Institute of Organic Chemistry, Johannes Kepler University LinzAltenberger Strasse 69, 4040 Linz (Austria)
| | - Alexander Jilek
- Chair of Bioinformatics, Department of Biotechnology, University of Natural Resources and Life SciencesMuthgasse 18, 1190 Vienna (Austria)
- Institute of Organic Chemistry, Johannes Kepler University LinzAltenberger Strasse 69, 4040 Linz (Austria)
- Institute of Molecular Biology, Austrian Academy of SciencesBillrothstrasse 11, 5020 Salzburg (Austria)
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18
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Wong ESW, Papenfuss AT, Whittington CM, Warren WC, Belov K. A limited role for gene duplications in the evolution of platypus venom. Mol Biol Evol 2011; 29:167-77. [PMID: 21816864 DOI: 10.1093/molbev/msr180] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Gene duplication followed by adaptive selection is believed to be the primary driver of venom evolution. However, to date, no studies have evaluated the importance of gene duplications for venom evolution using a genomic approach. The availability of a sequenced genome and a venom gland transcriptome for the enigmatic platypus provides a unique opportunity to explore the role that gene duplication plays in venom evolution. Here, we identify gene duplication events and correlate them with expressed transcripts in an in-season venom gland. Gene duplicates (1,508) were identified. These duplicated pairs (421), including genes that have undergone multiple rounds of gene duplications, were expressed in the venom gland. The majority of these genes are involved in metabolism and protein synthesis not toxin functions. Twelve secretory genes including serine proteases, metalloproteinases, and protease inhibitors likely to produce symptoms of envenomation such as vasodilation and pain were detected. Only 16 of 107 platypus genes with high similarity to known toxins evolved through gene duplication. Platypus venom C-type natriuretic peptides and nerve growth factor do not possess lineage-specific gene duplicates. Extensive duplications, believed to increase the potency of toxic content and promote toxin diversification, were not found. This is the first study to take a genome-wide approach in order to examine the impact of gene duplication on venom evolution. Our findings support the idea that adaptive selection acts on gene duplicates to drive the independent evolution and functional diversification of similar venom genes in venomous species. However, gene duplications alone do not explain the "venome" of the platypus. Other mechanisms, such as alternative splicing and mutation, may be important in venom innovation.
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Affiliation(s)
- Emily S W Wong
- Faculty of Veterinary Science, The University of Sydney, Sydney, New South Wales, Australia.
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19
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Jilek A, Mollay C, Lohner K, Kreil G. Substrate specificity of a peptidyl-aminoacyl-L/D-isomerase from frog skin. Amino Acids 2011; 42:1757-64. [PMID: 21424715 PMCID: PMC3325411 DOI: 10.1007/s00726-011-0890-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 03/09/2011] [Indexed: 12/14/2022]
Abstract
In the skin of fire-bellied toads (Bombina species), an aminoacyl-l/d-isomerase activity is present which catalyses the post-translational isomerization of the l- to the d-form of the second residue of its substrate peptides. Previously, this new type of enzyme was studied in some detail and genes potentially coding for similar polypeptides were found to exist in several vertebrate species including man. Here, we present our studies to the substrate specificity of this isomerase using fluorescence-labeled variants of the natural substrate bombinin H with different amino acids at positions 1, 2 or 3. Surprisingly, this enzyme has a rather low selectivity for residues at position 2 where the change of chirality at the alpha-carbon takes place. In contrast, a hydrophobic amino acid at position 1 and a small one at position 3 of the substrate are essential. Interestingly, some peptides containing a Phe at position 3 also were substrates. Furthermore, we investigated the role of the amino-terminus for substrate recognition. In view of the rather broad specificity of the frog isomerase, we made a databank search for potential substrates of such an enzyme. Indeed, numerous peptides of amphibia and mammals were found which fulfill the requirements determined in this study. Expression of isomerases with similar characteristics in other species can therefore be expected to catalyze the formation of peptides containing d-amino acids.
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Affiliation(s)
- Alexander Jilek
- Institute of Organic Chemistry, Johannes Kepler University Linz, Altenberger Str. 69, 4040, Linz, Austria.
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20
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Bai L, Romanova EV, Sweedler JV. Distinguishing endogenous D-amino acid-containing neuropeptides in individual neurons using tandem mass spectrometry. Anal Chem 2011; 83:2794-800. [PMID: 21388150 DOI: 10.1021/ac200142m] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
RNA-based protein synthesis produces L-amino acid-containing proteins and peptides. D-amino acid-containing peptides (DAACPs) can be generated from L-amino acid peptides via post-translational modification. In the nervous system, the conformational change of a single L-amino acid in a peptide to its D-form results in altered bioactivity, with some DAACPs having orders-of-magnitude enhanced efficacy. However, this modification is often overlooked when characterizing endogenous peptides. Here, with the use of matrix-assisted laser desorption ionization (MALDI) time-of-flight (TOF)/TOF mass spectrometry, neuropeptides that have the second residue isomerized to the D-isoform are distinguished from their L-epimers via differences in the relative amounts of specific fragment ions during tandem MS. With the appropriate fragment ions chosen, and in some cases with the use of metal adducts, epimer discrimination is optimized. Specifically, the cardioexcitatory peptide Asn-(D)Trp-Phe-amide (NdWFa) was assayed directly from neurons isolated from the sea slug Aplysia californica; the fraction of the peptide with the second residue (W) in the D- versus L-form was 90 ± 10%. We demonstrate that this approach is well suited for confirming DAACPs directly from cells and tissue, advancing our understanding of the l to d modification and the role it plays in cell-to-cell signaling.
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Affiliation(s)
- Lu Bai
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, Illinois 61801, USA
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21
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Koh JMS, Chow SJP, Crossett B, Kuchel PW. Mammalian peptide isomerase: platypus-type activity is present in mouse heart. Chem Biodivers 2010; 7:1603-11. [PMID: 20564672 DOI: 10.1002/cbdv.200900300] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Male platypus (Ornithorhynchus anatinus) venom has a peptidyl aminoacyl L/D-isomerase (hereafter called peptide isomerase) that converts the second amino acid residue in from the N-terminus from the L- to the D-form, and vice versa. A reversed-phase high-performance liquid chromatography (RP-HPLC) assay has been developed to monitor the interconversion using synthetic hexapeptides derived from defensin-like peptide-2 (DLP-2) and DLP-4 as substrates. It was hypothesised that animals other than the platypus would have peptide isomerase with the same substrate specificity. Accordingly, eight mouse tissues were tested and heart was shown to have the activity. This is notable for being the first evidence of a peptide isomerase being present in a higher mammal and heralds finding the activity in man.
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Affiliation(s)
- Jennifer M S Koh
- School of Molecular Biosciences, Building G08, University of Sydney, NSW 2006, Australia
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22
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Abstract
The monotremes (the echidnas and the platypus) display both mammalian and reptilian features. Male monotremes have a bilateral crural gland that is connected via a duct to a spur on each hind limb. Male echidnas appear not to use their spurs as weapons in aggressive acts, but the crural system may have a role in reproductive behaviour because it appears only to be active during the breeding season. The secretions produced by the echidna’s crural gland have not hitherto been biochemically or pharmacologically characterised. We used reverse-phase high-performance liquid chromatography (RP-HPLC) to separate the components of echidna venom and compared the chromatograms with those from platypus venom. The echidna venom appears to contain fewer proteins and peptides than platypus venom; however, it appears to have defensin-like peptides that behave similarly on RP-HPLC to those in platypus venom. Like platypus venom, echidna venom has peptidyl aminoacyl l/d-peptide isomerase activity. An RP-HPLC-based assay showed that the second amino acid residue, of a probe synthetic hexapeptide, was converted into the d-form, when incubated with echidna venom.
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Kita M, Black DS, Ohno O, Yamada K, Kigoshi H, Uemura D. Duck-Billed Platypus Venom Peptides Induce Ca2+ Influx in Neuroblastoma Cells. J Am Chem Soc 2009; 131:18038-9. [DOI: 10.1021/ja908148z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Masaki Kita
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan, School of Chemistry, The University of New South Wales, UNSW Sydney, NSW 2052, Australia, Department of Biosciences and Informatics, Keio University, Hiyoshi 3-14-1, Yokohama 223-8522, Japan, and Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8602, Japan
| | - David StC. Black
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan, School of Chemistry, The University of New South Wales, UNSW Sydney, NSW 2052, Australia, Department of Biosciences and Informatics, Keio University, Hiyoshi 3-14-1, Yokohama 223-8522, Japan, and Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8602, Japan
| | - Osamu Ohno
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan, School of Chemistry, The University of New South Wales, UNSW Sydney, NSW 2052, Australia, Department of Biosciences and Informatics, Keio University, Hiyoshi 3-14-1, Yokohama 223-8522, Japan, and Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8602, Japan
| | - Kaoru Yamada
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan, School of Chemistry, The University of New South Wales, UNSW Sydney, NSW 2052, Australia, Department of Biosciences and Informatics, Keio University, Hiyoshi 3-14-1, Yokohama 223-8522, Japan, and Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8602, Japan
| | - Hideo Kigoshi
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan, School of Chemistry, The University of New South Wales, UNSW Sydney, NSW 2052, Australia, Department of Biosciences and Informatics, Keio University, Hiyoshi 3-14-1, Yokohama 223-8522, Japan, and Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8602, Japan
| | - Daisuke Uemura
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan, School of Chemistry, The University of New South Wales, UNSW Sydney, NSW 2052, Australia, Department of Biosciences and Informatics, Keio University, Hiyoshi 3-14-1, Yokohama 223-8522, Japan, and Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8602, Japan
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Ollivaux C, Gallois D, Amiche M, Boscaméric M, Soyez D. Molecular and cellular specificity of post-translational aminoacyl isomerization in the crustacean hyperglycaemic hormone family. FEBS J 2009; 276:4790-802. [PMID: 19664061 DOI: 10.1111/j.1742-4658.2009.07180.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
D-aminoacyl residues have been detected in various animal peptides from several taxa, especially vertebrates and arthropods. This unusual polymorphism was shown to occur in isoforms of the crustacean hyperglycaemic hormone (CHH) of the American lobster because a D-phenylalanyl residue was found in position 3 of the sequence (CHH and D-Phe3 CHH). In the present study, we report the detailed strategy used to characterize, in the lobster neuroendocrine system, isomers of another member of the CHH family, vitellogenesis inhibiting hormone (VIH). We have demonstrated that the fourth residue is either an L- or a D- tryptophanyl residue (VIH and D-Trp4 VIH). Furthermore, use of antisera specifically recognizing the epimers of CHH and VIH reveals that aminoacyl isomerization occurs in specialized cells of the X organ-sinus gland neurosecretory system and that the D-forms of the two neuropeptides are not only present in the same cells, but, importantly, also are co-packaged within the same secretory vesicles.
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Affiliation(s)
- Céline Ollivaux
- Université Pierre et Marie Curie-Paris 06, UMR 7150 Mer et Santé, Equipe Physiologie Comparée des Erythrocytes, Station Biologique de Roscoff, France.
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25
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Bai L, Sheeley S, Sweedler JV. Analysis of Endogenous D-Amino Acid-Containing Peptides in Metazoa. ACTA ACUST UNITED AC 2009; 1:7-24. [PMID: 20490347 DOI: 10.1007/s12566-009-0001-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Peptides are chiral molecules with their structure determined by the composition and configuration of their amino acid building blocks. The naturally occurring amino acids, except glycine, possess two chiral forms. This allows the formation of multiple peptide diastereomers that have the same sequence. Although living organisms use L-amino acids to make proteins, a group of D-amino acid-containing peptides (DAACPs) has been discovered in animals that have at least one of their residues isomerized to the D-form via an enzyme-catalyzed process. In many cases, the biological functions of these peptides are enhanced due to this structural conversion. These DAACPs are different from those known to occur in bacterial cell wall and antibiotic peptides, the latter of which are synthesized in a ribosome-independent manner. DAACPs have now also been identified in a number of distinct groups throughout the Metazoa. Their serendipitous discovery has often resulted from discrepancies observed in bioassays or in chromatographic behavior between natural peptide fractions and peptides synthesized according to a presumed all-L sequence. Because this L-to-D post-translational modification is subtle and not detectable by most sequence determination approaches, it is reasonable to suspect that many studies have overlooked this change; accordingly, DAACPs may be more prevalent than currently thought. Although diastereomer separation techniques developed with synthetic peptides in recent years have greatly aided in the discovery of natural DAACPs, there is a need for new, more robust methods for naturally complex samples. In this review, a brief history of DAACPs in animals is presented, followed by discussion of a variety of analytical methods that have been used for diastereomeric separation and detection of peptides.
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Affiliation(s)
- Lu Bai
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
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26
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Whittington CM, Koh JM, Warren WC, Papenfuss AT, Torres AM, Kuchel PW, Belov K. Understanding and utilising mammalian venom via a platypus venom transcriptome. J Proteomics 2009; 72:155-64. [DOI: 10.1016/j.jprot.2008.12.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Accepted: 12/11/2008] [Indexed: 01/10/2023]
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27
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Ho J, Coote ML. pKa Calculation of Some Biologically Important Carbon Acids - An Assessment of Contemporary Theoretical Procedures. J Chem Theory Comput 2009; 5:295-306. [DOI: 10.1021/ct800335v] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Junming Ho
- ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
| | - Michelle L. Coote
- ARC Centre of Excellence for Free-Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
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28
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Abstract
An anatomical feature of the platypus (Ornithorhynchus anatinus) that is seen in only one other mammal, the echidna, is that the male has a crural glandular system that produces venom that is used for defence and territorial–breeding functions; whether the echidna is similarly venomous is not yet established. Platypus venom contains many novel proteins and peptides that are different from those in reptilian venom. It also causes pain and symptoms that are not experienced by any other kind of envenomation. Five types of proteins and peptides have been isolated and identified from platypus venom, namely: defensin-like peptides (DLPs); Ornithorhynchus venom C-type natriuretic peptides (OvCNPs); Ornithorhynchus nerve growth factor; hyaluronidase; and l-to-d-peptide isomerase. The structures of DLPs and OvCNPs have already been studied and they are very similar to β-defensin-12 and mammalian C-type natriuretic peptides, respectively. A special mammalian l-to-d-peptide isomerase that is responsible for interconverting the l- and d-peptide isomers is also found in platypus venom. Isomerase activity has recently been discovered in platypus tissues other than the venom gland. It is possible that similar kinds of enzymes might exist in other mammals and play important, as yet unknown, biological roles. Considering the fact that some animal venoms have already been widely used in pharmaceutical applications, research into platypus venom may lead to the discovery of new molecules and potent drugs that are useful biomedical tools.
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29
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Zangger K, Gößler R, Khatai L, Lohner K, Jilek A. Structures of the glycine-rich diastereomeric peptides bombinin H2 and H4. Toxicon 2008; 52:246-54. [DOI: 10.1016/j.toxicon.2008.05.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Revised: 04/30/2008] [Accepted: 05/01/2008] [Indexed: 11/26/2022]
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30
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Whittington CM, Papenfuss AT, Kuchel PW, Belov K. Expression patterns of platypus defensin and related venom genes across a range of tissue types reveal the possibility of broader functions for OvDLPs than previously suspected. Toxicon 2008; 52:559-65. [PMID: 18662710 DOI: 10.1016/j.toxicon.2008.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 06/28/2008] [Accepted: 07/01/2008] [Indexed: 11/30/2022]
Abstract
The platypus, as an egg-laying mammal, displays an unusual mixture of reptilian and mammalian characteristics. It is also venomous, and further investigations into its little-studied venom may lead to the development of novel pharmaceuticals and drug targets and provide insights into the origins of mammalian venom. Here we investigate the expression patterns of antimicrobial genes called defensins, and also the venom peptides called defensin-like peptides (OvDLPs). We show, in the first expression study on any platypus venom gene, that the OvDLPs are expressed in a greater range of tissues than would be expected for genes with specific venom function, and thus that they may have a wider role than previously suspected.
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Affiliation(s)
- Camilla M Whittington
- Faculty of Veterinary Science, RMC Gunn B19, University of Sydney, NSW 2006, Australia
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31
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Han Y, Huang F, Jiang H, Liu L, Wang Q, Wang Y, Shao X, Chi C, Du W, Wang C. Purification and structural characterization of a d-amino acid-containing conopeptide, conomarphin, from Conus marmoreus. FEBS J 2008; 275:1976-87. [DOI: 10.1111/j.1742-4658.2008.06352.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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32
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Ewing MA, Wang J, Sheeley SA, Sweedler JV. Detecting D-amino acid-containing neuropeptides using selective enzymatic digestion. Anal Chem 2008; 80:2874-80. [PMID: 18341354 DOI: 10.1021/ac7025173] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neuropeptides, gene products that undergo extensive post-translational modification (PTM), are frequently characterized using mass spectrometry (MS). One PTM in particular, the conversion of an L-amino acid to a D-amino acid, has no associated mass shift. Therefore, this PTM is difficult to evaluate using MS alone, especially in complex peptide mixtures. Here, enzymatic digestion using microsomal alanyl aminopeptidase is combined with MS characterization. This enzyme selectively degrades peptides lacking a D-amino acid in the second position from the N-terminus. By comparing a sample before and after digestion, D-amino acid-containing peptides (DAACPs) present in small quantities in a complex mixture can be identified, even among much larger quantities of other non-DAACPs. Protocols that use microsomal alanyl aminopeptidase as a discovery-enabling agent are described and validated by identifying a known DAACP from the Aplysia californica abdominal ganglion.
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Affiliation(s)
- Michael A Ewing
- Department of Chemistry and the Beckman Institute, University of Illinois, Urbana, Illinois 61801, USA
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33
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Bansal PS, Torres AM, Crossett B, Wong KKY, Koh JMS, Geraghty DP, Vandenberg JI, Kuchel PW. Substrate specificity of platypus venom L-to-D-peptide isomerase. J Biol Chem 2007; 283:8969-75. [PMID: 18158286 DOI: 10.1074/jbc.m709762200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The L-to-D-peptide isomerase from the venom of the platypus (Ornithorhyncus anatinus) is the first such enzyme to be reported for a mammal. In delineating its catalytic mechanism and broader roles in the animal, its substrate specificity was explored. We used N-terminal segments of defensin-like peptides DLP-2 and DLP-4 and natriuretic peptide OvCNP from the venom as substrates. The DLP analogues IMFsrs and ImFsrs (srs is a solubilizing chain; lowercase letters denote D-amino acid) were effective substrates for the isomerase; it appears to recognize the N-terminal tripeptide sequence Ile-Xaa-Phe-. A suite of 26 mutants of these hexapeptides was synthesized by replacing the second residue (Met) with another amino acid, viz. Ala, alpha-aminobutyric acid, Ile, Leu, Lys, norleucine, Phe, Tyr, and Val. It was shown that mutant peptides incorporating norleucine and Phe are substrates and exhibit L- or D-amino acid isomerization, but mutant peptides that contain residues with shorter, beta-branched or long side chains with polar terminal groups, viz. Ala, alpha-aminobutyric acid, Ile, Val, Leu, Lys, and Tyr, respectively, are not substrates. It was demonstrated that at least three N-terminal amino acid residues are absolutely essential for L-to-D-isomerization; furthermore, the third amino acid must be a Phe residue. None of the hexapeptides based on LLH, the first three residues of OvCNP, were substrates. A consistent 2-base mechanism is proposed for the isomerization; abstraction of a proton by 1 base is concomitant with delivery of a proton by the conjugate acid of a second base.
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Affiliation(s)
- Paramjit S Bansal
- School of Molecular and Microbial Biosciences, University of Sydney, New South Wales 2006, Australia
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Dutertre S, Lumsden NG, Alewood PF, Lewis RJ. Isolation and characterisation of conomap-Vt, ad-amino acid containing excitatory peptide from the venom of a vermivorous cone snail. FEBS Lett 2006; 580:3860-6. [PMID: 16797543 DOI: 10.1016/j.febslet.2006.06.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Revised: 05/22/2006] [Accepted: 06/02/2006] [Indexed: 11/19/2022]
Abstract
Cone snail venom is a rich source of bioactives, in particular small disulfide rich peptides that disrupt synaptic transmission. Here, we report the discovery of conomap-Vt (Conp-Vt), an unusual linear tetradecapeptide isolated from Conus vitulinus venom. The sequence displays no homology to known conopeptides, but displays significant homology to peptides of the MATP (myoactive tetradecapeptide) family, which are important endogenous neuromodulators in molluscs, annelids and insects. Conp-Vt showed potent excitatory activity in several snail isolated tissue preparations. Similar to ACh, repeated doses of Conp-Vt were tachyphylactic. Since nicotinic and muscarinic antagonists failed to block its effect and Conp-Vt desensitised tissue remained responsive to ACh, it appears that Conp-Vt contractions were non-cholinergic in origin. Finally, biochemical studies revealed that Conp-Vt is the first member of the MATP family with a d-amino acid. Interestingly, the isomerization of L-Phe to D-Phe enhanced biological activity, suggesting that this post-translational modified conopeptide may have evolved for prey capture.
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Affiliation(s)
- Sébastien Dutertre
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, 4072 Qld, Australia
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35
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Torres AM, Tsampazi M, Kennett EC, Belov K, Geraghty DP, Bansal PS, Alewood PF, Kuchel PW. Characterization and isolation of L-to-D-amino-acid-residue isomerase from platypus venom. Amino Acids 2006; 32:63-8. [PMID: 16729187 DOI: 10.1007/s00726-006-0346-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Accepted: 03/15/2006] [Indexed: 10/24/2022]
Abstract
Platypus venom contains an isomerase that reversibly interconverts the second amino-acid residue in some peptides between the L-form and the D-form. The enzyme acts on the natriuretic peptides OvCNPa and OvCNPb, and on the defensin-like peptides DLP-2 and DLP-4, but it does not act on DLP-1. While the isomerization of DLP-2 to DLP-4 is inhibited by the amino-peptidase inhibitor amastatin, it is not affected by the leucine amino-peptidase inhibitor bestatin. The enzyme, that is only present in minute quantities in an extract of the venom gland, is thermally stable up to 55 degrees C, and it was found by anion-exchange chromatography to be acidic. Isolation of the isomerase was carried out by combined ion-exchange chromatography and reverse-phase high performance liquid chromatography (HPLC).
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Affiliation(s)
- A M Torres
- School of Molecular and Microbial Biosciences, University of Sydney, Sydney, Australia
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