1
|
Li C, Qin R, Liu R, Miao S, Yang P. Functional amyloid materials at surfaces/interfaces. Biomater Sci 2018; 6:462-472. [PMID: 29435550 DOI: 10.1039/c7bm01124e] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
With the development of nanotechnology, functional amyloid materials are drawing increasing attention, and numerous remarkable applications are emerging. Amyloids, defined as a class of supramolecular assemblies of misfolded proteins or peptides into β-sheet fibrils, have evolved in many new respects and offer abundant chemical/biological functions. These proteinaceous micro/nano-structures provide excellent biocompatibility, rich phase behaviours, strong mechanical properties, and stability at interfaces not only in nature but also in functional materials, displaying versatile interactions with surfaces/interfaces that have been widely adopted in bioadhesion, synthetic biology, and composites. Overall, functional amyloids at surfaces/interfaces have excellent potential applications in next-generation biotechnology and biomaterials.
Collapse
Affiliation(s)
- Chen Li
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Xi'an 710119, China.
| | | | | | | | | |
Collapse
|
2
|
Sacharz J, Wesełucha-Birczyńska A, Zięba-Palus J, Lewandowski MH, Kowalski R, Palus K, Chrobok Ł, Moskal P, Birczyńska M, Sozańska A. Epileptic rat brain tissue analyzed by 2D correlation Raman spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 188:581-588. [PMID: 28772144 DOI: 10.1016/j.saa.2017.07.046] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 07/07/2017] [Accepted: 07/24/2017] [Indexed: 06/07/2023]
Abstract
Absence epilepsy is the neurological disorder characterized by the pathological spike-and wave discharges present in the electroencephalogram, accompanying a sudden loss of consciousness. Experiments were performed on brain slices obtained from young male WAG/Rij rats (2-3weeks old), so that they were sampled before the appearance of brain-damaging seizures symptoms. Two differing brain areas of the rats' brain tissue were studied: the somatosensory cortex (Sc) and the dorsal lateral geniculate nucleus of the thalamus (DLG). The Raman spectra of the fresh brain scraps, kept during measurements in artificial cerebrospinal fluid, were collected using as an excitation source 442nm, 514.5nm, 785nm and 1064nm laser line. The average spectra were analyzed by 2D correlation method regarding laser line as an external perturbation. In 2D synchronous spectra positive auto-peaks corresponding to the CC stretching and amide I band vibrations show maxima at 1660cm-1 and 1662cm-1 for Sc and DLG, respectively. The prominent auto-peak at 2937cm-1, originated from the CH3 mode in DLG brain area, seems to indicate the importance of methylation, considered to be significant in epileptogenesis. Synchronous and asynchronous correlations peaks, glutamic acid and gamma-aminobutyric acid (GABA), appear in Sc and DLG, respectively. In the 1730-1600cm-1 range occur cross-peaks which appearance might be triggered by glial fibrillary acidic protein (GFAP) activation.
Collapse
Affiliation(s)
- Julia Sacharz
- Faculty of Chemistry, Jagiellonian University, Kraków, Poland
| | | | | | - Marian H Lewandowski
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | | | - Katarzyna Palus
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Łukasz Chrobok
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Paulina Moskal
- Faculty of Chemistry, Jagiellonian University, Kraków, Poland
| | - Malwina Birczyńska
- The Department of Infectious Diseases, The University Hospital, Kraków, Poland
| | | |
Collapse
|
3
|
Caetano-Silva ME, Alves RC, Lucena GN, Frem RCG, Bertoldo-Pacheco MT, Lima-Pallone JA, Netto FM. Synthesis of whey peptide-iron complexes: Influence of using different iron precursor compounds. Food Res Int 2017; 101:73-81. [PMID: 28941699 DOI: 10.1016/j.foodres.2017.08.056] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 08/11/2017] [Accepted: 08/25/2017] [Indexed: 10/18/2022]
Abstract
Iron-binding peptides are an alternative for increasing the bioavailability of iron and to decreasing its pro-oxidant effect. This study aimed to synthesize and characterize peptide-iron complexes using FeCl2 or FeSO4 as the iron precursor compounds. Whey protein isolate (WPI), WPI hydrolyzed with pancreatin, and its fractions obtained via ultrafiltration (cut-off 5kDa) were used as ligands. The fluorescence intensity of the ligands significantly decreased as the iron concentration increased as a result of metal coordination with the iron-binding sites, which may have led to changes in the microenvironment of tryptophan. For both iron precursor compounds, the primary iron-binding site was carboxylate groups, and the linkage occurred via a bidentate coordination mode with two vibrational modes assigned to the COOFe linkage. However, infrared spectroscopy and thermal analysis results showed that the dynamics of the interaction is different for the iron precursor. The iron source may be of great importance because it may impact iron absorption and the pro-oxidant effect of the mineral.
Collapse
Affiliation(s)
- Maria Elisa Caetano-Silva
- Faculty of Food Engineering, University of Campinas, UNICAMP, Monteiro Lobato 80, 13083-862 Campinas, SP, Brazil.
| | - Renata Carolina Alves
- Institute of Chemistry, São Paulo State University, UNESP, Prof. Francisco Degni 55, PO Box 355, 14800-970 Araraquara, SP, Brazil.
| | - Guilherme Nunes Lucena
- Institute of Chemistry, São Paulo State University, UNESP, Prof. Francisco Degni 55, PO Box 355, 14800-970 Araraquara, SP, Brazil.
| | - Regina Célia Galvão Frem
- Institute of Chemistry, São Paulo State University, UNESP, Prof. Francisco Degni 55, PO Box 355, 14800-970 Araraquara, SP, Brazil.
| | - Maria Teresa Bertoldo-Pacheco
- Center of Food Science and Quality, Institute of Food Technology, ITAL, Brasil Ave 2880, 13070-178 Campinas, SP, Brazil.
| | - Juliana Azevedo Lima-Pallone
- Faculty of Food Engineering, University of Campinas, UNICAMP, Monteiro Lobato 80, 13083-862 Campinas, SP, Brazil.
| | - Flavia Maria Netto
- Faculty of Food Engineering, University of Campinas, UNICAMP, Monteiro Lobato 80, 13083-862 Campinas, SP, Brazil.
| |
Collapse
|
4
|
Krishnan BP, Rai R, Asokan A, Sureshan KM. Crystal-to-Crystal Synthesis of Triazole-Linked Pseudo-proteins via Topochemical Azide-Alkyne Cycloaddition Reaction. J Am Chem Soc 2016; 138:14824-14827. [PMID: 27791357 DOI: 10.1021/jacs.6b07538] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Isosteric replacement of amide bond(s) of peptides with surrogate groups is an important strategy for the synthesis of peptidomimetics (pseudo-peptides). Triazole is a well-recognized bio-isostere for peptide bonds, and peptides with one or more triazole units are of great interest for different applications. We have used a catalyst-free and solvent-free method, viz., topochemical azide-alkyne cycloaddition (TAAC) reaction, to synthesize pseudo-proteins with repeating sequences. A designed β-sheet-forming l-Ala-l-Val dipeptide containing azide and alkyne at its termini (N3-Ala-Val-NHCH2C≡CH, 1) was synthesized. Single-crystal XRD analysis of the dipeptide 1 showed parallel β-sheet arrangement along the b-direction and head-to-tail arrangement of such β-sheets along the c-direction. This head-to-tail arrangement along the c-direction places the complementary reacting motifs, viz., azide and alkyne, of adjacent molecules in proximity. The crystals of dipeptide 1, upon heating at 85 °C, underwent crystal-to-crystal polymerization, giving 1,4-triazole-linked pseudo-proteins. This TAAC polymerization was investigated by various time-dependent techniques, such as NMR, IR, DSC, and PXRD. The crystal-to-crystal nature of this transformation was revealed from polarizing microscopy and PXRD experiments, and the regiospecificity of triazole formation was evidenced from various NMR techniques. The MALDI-TOF spectrum showed the presence of pseudo-proteins >7 kDa.
Collapse
Affiliation(s)
- Baiju P Krishnan
- School of Chemistry, Indian Institute of Science Education and Research , Thiruvananthapuram, Kerala 695016, India
| | - Rishika Rai
- School of Chemistry, Indian Institute of Science Education and Research , Thiruvananthapuram, Kerala 695016, India
| | - Aromal Asokan
- School of Chemistry, Indian Institute of Science Education and Research , Thiruvananthapuram, Kerala 695016, India
| | - Kana M Sureshan
- School of Chemistry, Indian Institute of Science Education and Research , Thiruvananthapuram, Kerala 695016, India
| |
Collapse
|
5
|
Hassan MM. Enhanced Antistatic and Mechanical Properties of Corona Plasma Treated Wool Fabrics Treated with 2,3-Epoxypropyltrimethylammonium Chloride. Ind Eng Chem Res 2014. [DOI: 10.1021/ie500447p] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mohammad Mahbubul Hassan
- Food and Bio-based Products Group, AgResearch Limited, Cnr springs Road & Gerald Street, Lincoln, Christchurch 7647, New Zealand
| |
Collapse
|
6
|
Thomas DB, McGoverin CM, McGraw KJ, James HF, Madden O. Vibrational spectroscopic analyses of unique yellow feather pigments (spheniscins) in penguins. J R Soc Interface 2013; 10:20121065. [PMID: 23516063 DOI: 10.1098/rsif.2012.1065] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many animals extract, synthesize and refine chemicals for colour display, where a range of compounds and structures can produce a diverse colour palette. Feather colours, for example, span the visible spectrum and mostly result from pigments in five chemical classes (carotenoids, melanins, porphyrins, psittacofulvins and metal oxides). However, the pigment that generates the yellow colour of penguin feathers appears to represent a sixth, poorly characterized class of feather pigments. This pigment class, here termed 'spheniscin', is displayed by half of the living penguin genera; the larger and richer colour displays of the pigment are highly attractive. Using Raman and mid-infrared spectroscopies, we analysed yellow feathers from two penguin species (king penguin, Aptenodytes patagonicus; macaroni penguin, Eudyptes chrysolophus) to further characterize spheniscin pigments. The Raman spectrum of spheniscin is distinct from spectra of other feather pigments and exhibits 17 distinctive spectral bands between 300 and 1700 cm(-1). Spectral bands from the yellow pigment are assigned to aromatically bound carbon atoms, and to skeletal modes in an aromatic, heterocyclic ring. It has been suggested that the penguin pigment is a pterin compound; Raman spectra from yellow penguin feathers are broadly consistent with previously reported pterin spectra, although we have not matched it to any known compound. Raman spectroscopy can provide a rapid and non-destructive method for surveying the distribution of different classes of feather pigments in the avian family tree, and for correlating the chemistry of spheniscin with compounds analysed elsewhere. We suggest that the sixth class of feather pigments may have evolved in a stem-lineage penguin and endowed modern penguins with a costly plumage trait that appears to be chemically unique among birds.
Collapse
Affiliation(s)
- Daniel B Thomas
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA.
| | | | | | | | | |
Collapse
|
7
|
Immobilization of Mucor miehei Lipase onto Macroporous Aminated Polyethersulfone Membrane for Enzymatic Reactions. MEMBRANES 2012; 2:198-213. [PMID: 24958172 PMCID: PMC4021891 DOI: 10.3390/membranes2020198] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 03/28/2012] [Accepted: 03/29/2012] [Indexed: 11/25/2022]
Abstract
Immobilization of enzymes is one of the most promising methods in enzyme performance enhancement, including stability, recovery, and reusability. However, investigation of suitable solid support in enzyme immobilization is still a scientific challenge. Polyethersulfone (PES) and aminated PES (PES–NH2) were successfully synthesized as novel materials for immobilization. Membranes with various pore sizes (from 10–600 nm) based on synthesized PES and PES–NH2 polymers were successfully fabricated to be applied as bioreactors to increase the immobilized lipase performances. The influence of pore sizes, concentration of additives, and the functional groups that are attached on the PES backbone on enzyme loading and enzyme activity was studied. The largest enzyme loading was obtained by Mucor miehei lipase immobilized onto a PES–NH2 membrane composed of 10% of PES–NH2, 8% of dibutyl phthalate (DBP), and 5% of polyethylene glycol (PEG) (872.62 µg/cm2). Hydrolytic activity of the immobilized lipases indicated that the activities of biocatalysts are not significantly decreased by immobilization. From the reusability test, the lipase immobilized onto PES–NH2 showed a better constancy than the lipase immobilized onto PES (the percent recovery of the activity of the lipases immobilized onto PES–NH2 and PES are 97.16% and 95.37%, respectively), which indicates that this novel material has the potential to be developed as a bioreactor for enzymatic reactions.
Collapse
|
8
|
Castelletto V, Hamley IW, Harris PJF, Olsson U, Spencer N. Influence of the solvent on the self-assembly of a modified amyloid beta peptide fragment. I. Morphological investigation. J Phys Chem B 2009; 113:9978-87. [PMID: 19555054 DOI: 10.1021/jp902860a] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The solvent-induced transition between self-assembled structures formed by the peptide AAKLVFF is studied via electron microscopy, light scattering, and spectroscopic techniques. The peptide is based on a core fragment of the amyloid beta-peptide, KLVFF, extended by two alanine residues. AAKLVFF exhibits distinct structures of twisted fibrils in water or nanotubes in methanol. For intermediate water/methanol compositions, these structures are disrupted and replaced by wide filamentous tapes that appear to be lateral aggregates of thin protofilaments. The orientation of the beta-strands in the twisted tapes or nanotubes can be deduced from X-ray diffraction on aligned stalks, as well as FT-IR experiments in transmission compared to attenuated total reflection. Strands are aligned perpendicular to the axis of the twisted fibrils or the nanotubes. The results are interpreted in light of recent results on the effect of competitive hydrogen bonding upon self-assembly in soft materials in water/methanol mixtures.
Collapse
Affiliation(s)
- V Castelletto
- Department of Chemistry, The University of Reading, Reading RG6 6AD, UK.
| | | | | | | | | |
Collapse
|
9
|
Xie H, Becraft EJ, Baughman RH, Dalton AB, Dieckmann GR. Ranking the affinity of aromatic residues for carbon nanotubes by using designed surfactant peptides. J Pept Sci 2008; 14:139-51. [DOI: 10.1002/psc.978] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
10
|
Iconomidou VA, Chryssikos GD, Gionis V, Galanis AS, Cordopatis P, Hoenger A, Hamodrakas SJ. Amyloid fibril formation propensity is inherent into the hexapeptide tandemly repeating sequence of the central domain of silkmoth chorion proteins of the A-family. J Struct Biol 2006; 156:480-8. [PMID: 17056273 DOI: 10.1016/j.jsb.2006.08.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Revised: 07/28/2006] [Accepted: 08/25/2006] [Indexed: 01/08/2023]
Abstract
Peptide-analogues of the A and B families of silkmoth chorion proteins form amyloid fibrils under a variety of conditions [Iconomidou, V.A., Vriend, G. Hamodrakas, S.J. 2000. Amyloids protect the silkmoth oocyte and embryo. FEBS Lett. 479, 141-145; Iconomidou,V.A., Chryssikos, G.D.,Gionis, V., Vriend, G., Hoenger, A., Hamodrakas, S.J., 2001. Amyloid-like fibrils from an 18-residue peptide-analogue of a part of the central domain of the B-family of silkmoth chorion protein. FEBS Lett. 499, 268-273; Hamodrakas, S.J. Hoenger, A., Iconomidou, V. A., 2004 . Amyloid fibrillogenesis of silkmoth chorion protein peptide-analogues via a liquid crystalline intermediate phase. J. Struct. Biol. 145, 226-235.], which led us to propose that silkmoth chorion is a natural protective amyloid. In this study, we designed and synthesized two mutant peptide-analogues of the central conservative domain of the A family: (a) one, cA_m1, with a length half of that of the central domain of the A family, which folds and self-assembles, in various conditions, into amyloid fibrils very similar in properties and structure to the fibrils formed by the cA peptide, which corresponds to the entire length of the A family central domain [Iconomidou, V.A., Vriend, G. Hamodrakas, S.J. 2000. Amyloids protect the silkmoth oocyte and embryo. FEBS Lett. 479, 141-145.], in full support of our previous proposal, (b) the second, cA_m2, differing from cA_m1 at three positions, where three glutamates have replaced two valines and one alanine residues, does not form amyloid fibrils in any conditions. It appears that (a) the amyloidogenic properties of silkmoth chorion peptides are encoded into the tandemly repeating hexapeptides comprising the central domain of silkmoth chorion proteins, and, that (b) suitable mutations, properly and carefully designed, greatly affect the strong amyloidogenic properties inherent in certain aminoacid sequences and may inhibit amyloid formation.
Collapse
Affiliation(s)
- Vassiliki A Iconomidou
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece
| | | | | | | | | | | | | |
Collapse
|
11
|
Xie H, Ortiz-Acevedo A, Zorbas V, Baughman RH, Draper RK, Musselman IH, Dalton AB, Dieckmann GR. Peptide cross-linking modulated stability and assembly of peptide-wrapped single-walled carbon nanotubes. ACTA ACUST UNITED AC 2005. [DOI: 10.1039/b413262a] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
12
|
Gosal WS, Clark AH, Ross-Murphy SB. Fibrillar β-Lactoglobulin Gels: Part 1. Fibril Formation and Structure. Biomacromolecules 2004; 5:2408-19. [PMID: 15530058 DOI: 10.1021/bm049659d] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
As a prelude to experimental and theoretical work on the mechanical properties of fibrillar beta-lactoglobulin gels, this paper reports the structural characterization of beta-lactoglobulin fibrils by electron and atomic force microscopy (AFM), infrared and Raman spectroscopy, and powder X-ray diffraction. Aggregates formed by incubation of beta-lactoglobulin in various alcohol-water mixtures at pH 2, and in water-trifluoroethanol (TFE) at pH 7, were found to be wormlike (approximately 7 nm in width and <500 nm in length), with a "string-of-beads" appearance. Longer (approximately 7 nm in width, and >1 microm in length), smoother, and seemingly stiffer fibrils formed on heating aqueous beta-lactoglobulin solutions at pH 2 and low ionic strength, although there was little evidence for the higher-order structures common in most amyloid-forming systems. Time-lapse AFM also revealed differences in the formation of these two fibril types: thermally induced aggregation occurring more cooperatively, in keeping with a nucleation and growth process. Only short stiff-rods (<20 nm in length) formed on heating beta-lactoglobulin at pH 7, and only complex three-dimensional "amorphous"aggregates in alcohols other than TFE at this pH. Studies of all of the pH 2 fibrils from beta-lactoglobulin, by Raman and infrared spectroscopy confirmed beta-sheet as mediating the aggregation process. Interestingly, however, some evidence for de novo helix formation for the solvent-induced systems was obtained, although it remains to be seen whether this is actually incorporated into the fibril-structure. In contrast to other amyloid systems, X-ray powder diffraction provided no evidence for extensive repeating "crystalline" structures for any of the pH 2 beta-lactoglobulin fibrils. In relation to amyloid, the lactoglobulin fibrils bear more resemblance to protofilaments than to higher-order fibril structures, these latter appearing more convincingly for thermally induced insulin fibrils (pH 2) also included in the AFM study.
Collapse
Affiliation(s)
- Walraj S Gosal
- Department of Life Sciences, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NN, United Kingdom.
| | | | | |
Collapse
|
13
|
Hamodrakas SJ, Hoenger A, Iconomidou VA. Amyloid fibrillogenesis of silkmoth chorion protein peptide-analogues via a liquid-crystalline intermediate phase. J Struct Biol 2004; 145:226-35. [PMID: 14960373 DOI: 10.1016/j.jsb.2003.10.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2003] [Revised: 10/02/2003] [Indexed: 11/22/2022]
Abstract
Chorion, the major component of silkmoth eggshell, consists of the A and B classes of low-molecular weight structural proteins. Chorion protects the oocyte and the developing embryo from environmental hazards and this is due to the extraordinary physical and chemical properties of its constituent proteins. We have shown previously [FEBS Lett. 479 (2000) 141; 499 (2001) 268] that peptide-analogues of the A and B classes of chorion proteins form amyloid fibrils under a variety of conditions, which led us to propose that silkmoth chorion is a natural, protective amyloid. In this work, we present data showing conclusively that, the first main step of amyloid-like fibrillogenesis of chorion peptides is the formation of nuclei of liquid crystalline nature, which is reminiscent of spider-silk formation. We show that these liquid-crystalline nuclei (spherulites) 'collapse'/deteriorate to form amyloid fibrils in a spectacular manner, important, it seems, for chorion morphogenesis and amyloid fibrillogenesis in general. The molecular 'switch' causing this spectacular transformation is, most probably, a conformational transition to the structure of chorion peptides, from a left-handed parallel beta-helix to an antiparallel beta-pleated sheet. Apparently, these peptides were suitably designed to play this role, after millions of years of molecular evolution.
Collapse
Affiliation(s)
- S J Hamodrakas
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Athens 157 01, Greece.
| | | | | |
Collapse
|
14
|
Iconomidou VA, Chryssikos GD, Gionis V, Hoenger A, Hamodrakas SJ. FT-Raman spectroscopy as diagnostic tool of Congo red binding to amyloids. Biopolymers 2003; 72:185-92. [PMID: 12722114 DOI: 10.1002/bip.10344] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Chorion is the major component of silkmoth eggshell. More than 95% of its dry mass consists of the A and B families of low molecular weight structural proteins, which have remarkable mechanical and chemical properties protecting the oocyte and developing embryo from environmental hazards. We present data from FT-Raman spectroscopy of silkmoth chorion and amyloid-like fibrils formed from peptide analogues of chorion proteins, both unstained and stained by Congo red. The results show that FT-Raman spectroscopy is not a straightforward diagnostic tool for the specific interactions of Congo red with amyloids: a dilute aqueous solution of the Congo red dye at pH 5.5 and a thin solid film of the dye cast from this solution exhibit the same "diagnostic" Raman shifts relative to the neat Congo red dry powder as do amyloid fibrils formed from peptide analogues of chorion proteins stained by Congo red. An important consequence of this finding is that these shifts of the Raman active modes of Congo red are probably due to the formation of supramolecular dye aggregates in the presence of water. Therefore, this is not an appropriate diagnostic test for Congo red binding to amyloids.
Collapse
Affiliation(s)
- Vassiliki A Iconomidou
- Department of Cell Biology and Biophysics, University of Athens, Panepistimiopolis, Athens 157 01, Greece
| | | | | | | | | |
Collapse
|
15
|
Iconomidou VA, Chryssikos GD, Gionis V, Vriend G, Hoenger A, Hamodrakas SJ. Amyloid-like fibrils from an 18-residue peptide analogue of a part of the central domain of the B-family of silkmoth chorion proteins. FEBS Lett 2001; 499:268-73. [PMID: 11423129 DOI: 10.1016/s0014-5793(01)02510-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Chorion is the major component of silkmoth eggshell. More than 95% of its dry mass consists of the A and B families of low molecular weight structural proteins, which have remarkable mechanical and chemical properties, and protect the oocyte and the developing embryo from the environment. We present data from negative staining, Congo red binding, X-ray diffraction, Fourier transform-Raman, attenuated total reflectance infrared spectroscopy and modelling studies of a synthetic peptide analogue of a part of the central domain of the B family of silkmoth chorion proteins, indicating that this peptide folds and self-assembles, forming amyloid-like fibrils. These results support further our proposal, based on experimental data from a synthetic peptide analogue of the central domain of the A family of chorion proteins, that silkmoth chorion is a natural, protective amyloid [Iconomidou et al., FEBS Lett. 479 (2000) 141-145].
Collapse
Affiliation(s)
- V A Iconomidou
- Department of Cell Biology and Biophysics, University of Athens, Greece
| | | | | | | | | | | |
Collapse
|
16
|
Abstract
Chorion is the major component of silkmoth eggshell. More than 95% of its dry mass consists of proteins that have remarkable mechanical and chemical properties protecting the oocyte and the developing embryo from a wide range of environmental hazards. We present data from electron microscopy (negative staining and shadowing), X-ray diffraction and modeling studies of synthetic peptide analogues of silkmoth chorion proteins indicating that chorion is a natural amyloid. The folding and self-assembly models of chorion peptides strongly support the beta-sheet helix model of amyloid fibrils proposed recently by Blake and Serpell [Structure 4 (1996) 989-998].
Collapse
Affiliation(s)
- V A Iconomidou
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Greece
| | | | | |
Collapse
|