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Santoro A, Buonocore M, Grimaldi M, Napolitano E, D’Ursi AM. Monitoring the Conformational Changes of the Aβ(25-35) Peptide in SDS Micelles: A Matter of Time. Int J Mol Sci 2023; 24:ijms24020971. [PMID: 36674488 PMCID: PMC9867351 DOI: 10.3390/ijms24020971] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 12/28/2022] [Accepted: 12/31/2022] [Indexed: 01/07/2023] Open
Abstract
Alzheimer's disease is a neurodegenerative disease characterized by the formation of amyloid plaques constituted prevalently by amyloid peptides. Due to the well-known challenges related to the study in solution of these peptides, several membrane-mimicking systems such as micelle constituted by detergent-i.e., DPC and SDS-have been deeply investigated. Additionally, the strategy of studying short fragments instead of the full-length peptide turned out to be advantageous in exploring the structural properties of the different moieties in Aβ in order to reproduce its pathologic effects. Several studies reveal that among Aβ fragments, Aβ(25-35) is the shortest fragment able to reproduce the aggregation process. To enrich the structural data currently available, in the present work we decided to evaluate the conformational changes adopted by Aβ(25-35) in SDS combining CD and NMR spectroscopies at different times. From the solved structures, it emerges that Aβ(25-35) passes from an unordered conformation at the time of the constitution of the system to a more ordered and energetically favorable secondary structure at day 7, which is kept for 2 weeks. These preliminary data suggest that a relatively long time affects the kinetic in the aggregation process of Aβ(25-35) in a micellar system, favoring the stabilization and the formation of a soluble helix conformation.
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Affiliation(s)
- Angelo Santoro
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
- Department of Pharmacy, Scuola di Specializzazione in Farmacia Ospedaliera, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
| | - Michela Buonocore
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
- Department of Veterinary Pathology, University of Naples Federico II, Via Federico Delpino 1, 80137 Naples, Italy
| | - Manuela Grimaldi
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
| | - Enza Napolitano
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
- PhD Program in Drug Discovery and Development, Department of Pharmacy, University of Salerno, 84084 Fisciano, Italy
| | - Anna Maria D’Ursi
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
- Correspondence:
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Chhimpa N, Singh N, Puri N, Kayath HP. The Novel Role of Mitochondrial Citrate Synthase and Citrate in the Pathophysiology of Alzheimer's Disease. J Alzheimers Dis 2023; 94:S453-S472. [PMID: 37393492 PMCID: PMC10473122 DOI: 10.3233/jad-220514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2023] [Indexed: 07/03/2023]
Abstract
Citrate synthase is a key mitochondrial enzyme that utilizes acetyl-CoA and oxaloacetate to form citrate in the mitochondrial membrane, which participates in energy production in the TCA cycle and linked to the electron transport chain. Citrate transports through a citrate malate pump and synthesizes acetyl-CoA and acetylcholine (ACh) in neuronal cytoplasm. In a mature brain, acetyl-CoA is mainly utilized for ACh synthesis and is responsible for memory and cognition. Studies have shown low citrate synthase in different regions of brain in Alzheimer's disease (AD) patients, which reduces mitochondrial citrate, cellular bioenergetics, neurocytoplasmic citrate, acetyl-CoA, and ACh synthesis. Reduced citrate mediated low energy favors amyloid-β (Aβ) aggregation. Citrate inhibits Aβ25-35 and Aβ1-40 aggregation in vitro. Hence, citrate can be a better therapeutic option for AD by improving cellular energy and ACh synthesis, and inhibiting Aβ aggregation, which prevents tau hyperphosphorylation and glycogen synthase kinase-3 beta. Therefore, we need clinical studies if citrate reverses Aβ deposition by balancing mitochondrial energy pathway and neurocytoplasmic ACh production. Furthermore, in AD's silent phase pathophysiology, when neuronal cells are highly active, they shift ATP utilization from oxidative phosphorylation to glycolysis and prevent excessive generation of hydrogen peroxide and reactive oxygen species (oxidative stress) as neuroprotective action, which upregulates glucose transporter-3 (GLUT3) and pyruvate dehydrogenase kinase-3 (PDK3). PDK3 inhibits pyruvate dehydrogenase, which decreases mitochondrial-acetyl-CoA, citrate, and cellular bioenergetics, and decreases neurocytoplasmic citrate, acetyl-CoA, and ACh formation, thus initiating AD pathophysiology. Therefore, GLUT3 and PDK3 can be biomarkers for silent phase of AD.
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Affiliation(s)
- Neeraj Chhimpa
- Department of Pharmacology, Post Graduate Institute of Medical Education & Research, Chandigarh, India
- Department of Pharmacology, Meharishi Markandeshwar College of Medical Science & Research, Ambala, India
| | - Neha Singh
- Department of Pharmacology, Post Graduate Institute of Medical Education & Research, Chandigarh, India
| | - Nikkita Puri
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, India
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3
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Narsineni L, Rao PPN, Pham AT, Foldvari M. Peptide-Modified Gemini Surfactants as Delivery System Building Blocks with Dual Functionalities for Glaucoma Treatment: Gene Carriers and Amyloid-Beta (Aβ) Self-Aggregation Inhibitors. Mol Pharm 2022; 19:2737-2753. [PMID: 35802484 DOI: 10.1021/acs.molpharmaceut.2c00088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Retinal ganglion cell (RGC) neurodegeneration in glaucoma has potential links with amyloid-β (Aβ) deposition. Targeting the Aβ pathway was shown to reduce RGC apoptosis and protect RGCs from degeneration. We report exploratory studies on the amyloid Aβ40 aggregation inhibition properties of four cell adhesion peptide (CAP)-gemini surfactants that are intended as building blocks for gene carrier nanoparticles for glaucoma treatment. The CAP-gemini surfactants (18-7N(p1-4)-18) were evaluated as potential Aβ40 peptide aggregation inhibitors by a fluorescence kinetic assay and for their binding interactions with Aβ40 dimers by molecular docking studies. In vitro Aβ40 peptide aggregation inhibition studies showed that the 18-7N(p3)-18 and 18-7N(p1)-18 ligands inhibit Aβ40 peptide aggregation and prevent the formation of higher order structures. CDOCKER energies and CDOCKER interaction energies demonstrated that the CAP-gemini surfactants formed more stable complexes in the Aβ40 dimer assembly and underwent both polar and nonpolar interactions compared to CAP peptides alone. Also, 18-7N(p3)-18 showed a significantly lower CDOCKER energy compared to that of the unmodified gemini surfactant 18-7NH-18 (p < 0.0001) and 18-7N(p4)-18 (p < 0.001), 18-7N(p1)-18, and 18-7N(p2)-18. Similarly, 18-7N(p3)-18 showed a significantly lower CDOCKER interaction energy compared to that of 18-7NH-18, 18-7N(p4)-18 (p < 0.0001), and 18-7N(p2)-18 (p < 0.001), while 18-7N(p3)-18 and 18-7N(p1)-18 showed similar CDOCKER interaction energies. These studies suggest that a combination of both hydrophobic and electrostatic interactions contributes to the anti-Aβ40 aggregation activity of CAP-gemini surfactants. CAP-gemini surfactants showed 10-fold better Aβ40 peptide aggregation inhibition compared to previously reported values and could provide a new opportunity for glaucoma treatment as dual-functional gene carriers.
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4
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Maity D, Howarth M, Vogel MC, Magzoub M, Hamilton AD. Peptidomimetic-Based Vesicles Inhibit Amyloid-β Fibrillation and Attenuate Cytotoxicity. J Am Chem Soc 2021; 143:3086-3093. [PMID: 33600171 DOI: 10.1021/jacs.0c09967] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An interruption in Aβ homeostasis leads to the deposit of neurotoxic amyloid plaques and is associated with Alzheimer's disease. A supramolecular strategy based on the assembly of peptidomimetic agents into functional vesicles has been conceived for the simultaneous inhibition of Aβ42 fibrillation and expedited clearance of Aβ42 aggregates. Tris-pyrrolamide peptidomimetic, ADH-353, contains one hydrophobic N-butyl and two hydrophilic N-propylamine side chains and readily forms vesicles under physiological conditions. These vesicles completely rescue both mouse neuroblastoma N2a and human neuroblastoma SH-SY5Y cells from the cytotoxicity that follows from Aβ42 misfolding likely in mitochondria. Biophysical studies, including confocal imaging, demonstrate the biocompatibility and selectivity of the approach toward this aberrant protein assembly in cellular milieu.
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Affiliation(s)
- Debabrata Maity
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Madeline Howarth
- Biology Program, New York University Abu Dhabi, P.O. Box 129188, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
| | - Maria C Vogel
- Biology Program, New York University Abu Dhabi, P.O. Box 129188, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
| | - Mazin Magzoub
- Biology Program, New York University Abu Dhabi, P.O. Box 129188, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
| | - Andrew D Hamilton
- Department of Chemistry, New York University, New York, New York 10003, United States
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5
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Cao Y, Wang D, Zhou P, Zhao Y, Sun Y, Wang J. Influence of Conventional Surfactants on the Self-Assembly of a Bola Type Amphiphilic Peptide. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:5446-5455. [PMID: 28493723 DOI: 10.1021/acs.langmuir.7b00405] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Structural and morphological regulation is a distinctly important topic in peptide self-assembly, and is also regarded as the fundamental point in peptide-based biomaterials development. In this paper, we showed that adding anionic surfactant SDS to a bola amphiphilic peptide KI4K could result in the reconstruction of β-sheet secondary structure besides the changes in self-assembly morphologies from nanotubes to helical ribbons, nanofibers, or straight nanotapes according to the negatively stained transmission electron microscopy, atomic force microscopy, circular dichroism spectroscopy, and Fourier transform infrared spectroscopy results. The inducing effect of SDS was observed at both above and below its CMC but with different transformation rates. Through comparison to other surfactants, including CTAB, C12EO4, and AOT, we proposed that the transitions of KI4K self-assemblies induced by anionic surfactants could be mainly attributed to the effect of hydrophobic interaction and electrostatic attraction between surfactants and peptide molecules. Rheological property measurement and dye adsorption experiments were also carried out to evaluate the properties of hydrogels formed by the peptide/surfactant hybrids. The samples formed self-supporting hydrogels at proper SDS or AOT concentrations, and the charges of hydrogel could be regulated by peptide to surfactant ratio.
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Affiliation(s)
- Yueying Cao
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China) , 66 Changjiang West Road, Qingdao 266580, China
| | - Dong Wang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China) , 66 Changjiang West Road, Qingdao 266580, China
| | - Peng Zhou
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China) , 66 Changjiang West Road, Qingdao 266580, China
| | - Yurong Zhao
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China) , 66 Changjiang West Road, Qingdao 266580, China
| | - Yawei Sun
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China) , 66 Changjiang West Road, Qingdao 266580, China
| | - Jiqian Wang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China) , 66 Changjiang West Road, Qingdao 266580, China
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6
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Ahmed A, Shamsi A, Bano B. Characterizing harmful advanced glycation end-products (AGEs) and ribosylated aggregates of yellow mustard seed phytocystatin: Effects of different monosaccharides. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 171:183-192. [PMID: 27526342 DOI: 10.1016/j.saa.2016.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 07/20/2016] [Accepted: 08/04/2016] [Indexed: 06/06/2023]
Abstract
Advanced glycation end products (AGEs) are at the core of variety of diseases ranging from diabetes to renal failure and hence gaining wide consideration. This study was aimed at characterizing the AGEs of phytocystatin isolated from mustard seeds (YMP) when incubated with different monosaccharides (glucose, ribose and mannose) using fluorescence, ultraviolet, circular dichroism (CD) spectroscopy and microscopy. Ribose was found to be the most potent glycating agent as evident by AGEs specific fluorescence and absorbance. YMP exists as a molten globule like structure on day 24 as depicted by high ANS fluorescence and altered intrinsic fluorescence. Glycated YMP as AGEs and ribose induced aggregates were observed at day 28 and 32 respectively. In our study we have also examined the anti-aggregative potential of polyphenol, resveratrol. Our results suggested the anti-aggregative behavior of resveratrol as it prevented the in vitro aggregation of YMP, although further studies are required to decode the mechanism by which resveratrol prevents the aggregation.
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Affiliation(s)
- Azaj Ahmed
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, India
| | - Anas Shamsi
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, India
| | - Bilqees Bano
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, India.
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7
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In vitro disintegration of goat brain cystatin fibrils using conventional and gemini surfactants: Putative therapeutic intervention in amyloidoses. Int J Biol Macromol 2016; 93:493-500. [DOI: 10.1016/j.ijbiomac.2016.08.082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 08/26/2016] [Accepted: 08/29/2016] [Indexed: 01/01/2023]
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8
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Lu Q, Tang Q, Xiong Y, Qing G, Sun T. Protein/Peptide Aggregation and Amyloidosis on Biointerfaces. MATERIALS (BASEL, SWITZERLAND) 2016; 9:E740. [PMID: 28773858 PMCID: PMC5457079 DOI: 10.3390/ma9090740] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 08/12/2016] [Accepted: 08/25/2016] [Indexed: 12/27/2022]
Abstract
Recently, studies of protein/peptide aggregation, particularly the amyloidosis, have attracted considerable attention in discussions of the pathological mechanisms of most neurodegenerative diseases. The protein/peptide aggregation processes often occur at the membrane-cytochylema interface in vivo and behave differently from those occurring in bulk solution, which raises great interest to investigate how the interfacial properties of artificial biomaterials impact on protein aggregation. From the perspective of bionics, current progress in this field has been obtained mainly from four aspects: (1) hydrophobic-hydrophilic interfaces; (2) charged surface; (3) chiral surface; and (4) biomolecule-related interfaces. The specific physical and chemical environment provided by these interfaces is reported to strongly affect the adsorption of proteins, transition of protein conformation, and diffusion of proteins on the biointerface, all of which are ultimately related to protein assembly. Meanwhile, these compelling results of in vitro experiments can greatly promote the development of early diagnostics and therapeutics for the relevant neurodegenerative diseases. This paper presents a brief review of these appealing studies, and particular interests are placed on weak interactions (i.e., hydrogen bonding and stereoselective interactions) that are also non-negligible in driving amyloid aggregation at the interfaces. Moreover, this paper also proposes the future perspectives, including the great opportunities and challenges in this field as well.
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Affiliation(s)
- Qi Lu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China.
| | - Qiuhan Tang
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China.
| | - Yuting Xiong
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China.
| | - Guangyan Qing
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China.
| | - Taolei Sun
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China.
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China.
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9
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Jones BH, Martinez AM, Wheeler JS, Spoerke ED. Surfactant-induced assembly of enzymatically-stable peptide hydrogels. SOFT MATTER 2015; 11:3572-3580. [PMID: 25853589 DOI: 10.1039/c5sm00522a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The secondary structure of peptides in the presence of interacting additives is an important topic of study, having implications in the application of peptide science to a broad range of modern technologies. Surfactants constitute a class of biologically relevant compounds that are known to influence both peptide conformation and aggregation or assembly. We have characterized the secondary structure of a linear nonapeptide composed of a hydrophobic alanine/phenylalanine core flanked by hydrophilic acid/amine units. We show that the anionic surfactant sodium dodecyl sulfate (SDS) induces the formation of β-sheets and macroscopic gelation in this otherwise unstructured peptide. Through comparison to related additives, we propose that SDS-induced secondary structure formation is the result of amphiphilicity created by electrostatic binding of SDS to the peptide. In addition, we demonstrate a novel utility of surfactants in manipulating and stabilizing peptide nanostructures. SDS is used to simultaneously induce secondary structure in a peptide and to inhibit the activity of a model enzyme, resulting in a peptide hydrogel that is impervious to enzymatic degradation. These results complement our understanding of the behavior of peptides in the presence of interacting secondary molecules and provide new potential pathways for programmable organization of peptides by the addition of such components.
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Affiliation(s)
- Brad H Jones
- Sandia National Laboratories, Electronic, Optical, and Nano Materials, PO Box 5800, MS 1411, Albuquerque, NM 87185, USA.
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10
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Usachev K, Filippov A, Khairutdinov B, Antzutkin O, Klochkov V. NMR structure of the Arctic mutation of the Alzheimer’s Aβ(1–40) peptide docked to SDS micelles. J Mol Struct 2014. [DOI: 10.1016/j.molstruc.2014.08.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Bandyopadhyay S, Junjie RL, Lim B, Sanjeev R, Xin WY, Yee CK, Hui Melodies SM, Yow N, Sivaraman J, Chatterjee C. Solution structures and model membrane interactions of Ctriporin, an anti-methicillin-resistantStaphylococcus aureusPeptide from Scorpion Venom. Biopolymers 2014; 101:1143-53. [DOI: 10.1002/bip.22519] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 05/14/2014] [Accepted: 06/06/2014] [Indexed: 02/04/2023]
Affiliation(s)
| | | | - Brendan Lim
- School of Applied Science; Republic Polytechnic Singapore
| | - R. Sanjeev
- School of Applied Science; Republic Polytechnic Singapore
| | - Woon Yong Xin
- School of Applied Science; Republic Polytechnic Singapore
| | - Chong Kok Yee
- School of Applied Science; Republic Polytechnic Singapore
| | | | - Nicole Yow
- School of Applied Science; Republic Polytechnic Singapore
| | - J. Sivaraman
- Department of Biological Sciences; National University of Singapore; Singapore
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12
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Hong Z, Damodaran K, Asher SA. Sodium dodecyl sulfate monomers induce XAO peptide polyproline II to α-helix transition. J Phys Chem B 2014; 118:10565-75. [PMID: 25121643 PMCID: PMC4161145 DOI: 10.1021/jp504133m] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
XAO peptide (Ac–X2A7O2–NH2; X: diaminobutyric
acid side chain, −CH2CH2NH3+; O: ornithine side chain,
−CH2CH2CH2NH3+) in aqueous solution shows a predominantly polyproline II
(PPII) conformation without any detectable α-helix-like conformations.
Here we demonstrate by using circular dichroism (CD), ultraviolet
resonance Raman (UVRR) and nuclear magnetic resonance (NMR) spectroscopy
that sodium dodecyl sulfate (SDS) monomers bind to XAO and induce
formation of α-helix-like conformations. The stoichiometry and
the association constants of SDS and XAO were determined from the
XAO–SDS diffusion coefficients measured by pulsed field gradient
NMR. We developed a model for the formation of XAO–SDS aggregate
α-helix-like conformations. Using UVRR spectroscopy, we calculated
the Ramachandran ψ angle distributions of aggregated XAO peptides.
We resolved α-, π- and 310- helical conformations
and a turn conformation. XAO nucleates SDS aggregation at SDS concentrations
below the SDS critical micelle concentration. The XAO4–SDS16 aggregates have four SDS molecules bound to each XAO to
neutralize the four side chain cationic charges. We propose that the
SDS alkyl chains partition into a hydrophobic core to minimize the
hydrophobic area exposed to water. Neutralization of the flanking
XAO charges enables α-helix formation. Four XAO–SDS4 aggregates form a complex with an SDS alkyl chain-dominated
hydrophobic core and a more hydrophilic shell where one face of the
α-helix peptide contacts the water environment.
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Affiliation(s)
- Zhenmin Hong
- Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
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13
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Bhat SA, Bano B. Conformational behaviour and aggregation of chickpea cystatin in trifluoroethanol: effects of epicatechin and tannic acid. Arch Biochem Biophys 2014; 562:51-61. [PMID: 25173679 DOI: 10.1016/j.abb.2014.08.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 08/12/2014] [Accepted: 08/20/2014] [Indexed: 11/29/2022]
Abstract
Conformational alterations and aggregates of chickpea cystatin (CPC) were investigated upon sequential addition of trifluoroethanol (TFE) over a range of 0-70% v/v. CPC on 30% and 40% v/v TFE addition exhibited non-native β-sheet, altered intrinsic fluorescence, increased thioflavin T fluorescence, prominent red shifted shoulder peak in Congo red absorbance, and enhanced turbidity as well as Rayleigh scattering, suggesting the aggregate formation. TEM results confirmed the formation of fibrillar aggregates at 30% and 40% v/v TFE. On increasing concentration of TFE to 70% v/v, CPC showed retention of native-like secondary structure, increased intrinsic and ANS fluorescence. Thus our results show that favourable condition for fibrillation of CPC is in the range of 30-40% TFE. Moreover, anti-aggregational effects of polyphenols, epicatechin (EC) and tannic acid (TA) were analysed using ThT binding assay and other biophysical assays. EC and TA produced a concentration dependent decline in ThT fluorescence suggesting inhibition of the fibril formation. Furthermore, TA in comparison to EC, served as a more effective inhibitor against amyloid fibril formation of CPC. This work supports the universality of the amyloid-like aggregation not restricted to some special categories of protein and the fact that this aggregation can be prevented.
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Affiliation(s)
- Sheraz Ahmad Bhat
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, India
| | - Bilqees Bano
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, India.
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14
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Bandyopadhyay S, Ng BY, Chong C, Lim MZ, Gill SK, Lee KH, Sivaraman J, Chatterjee C. Micelle bound structure and DNA interaction of brevinin-2-related peptide, an antimicrobial peptide derived from frog skin. J Pept Sci 2014; 20:811-21. [DOI: 10.1002/psc.2673] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/23/2014] [Accepted: 06/13/2014] [Indexed: 11/11/2022]
Affiliation(s)
| | - Boon Yee Ng
- School of Applied Science; Republic Polytechnic; Singapore
| | | | - Ming Zhen Lim
- School of Applied Science; Republic Polytechnic; Singapore
| | | | - Ke Hui Lee
- School of Applied Science; Republic Polytechnic; Singapore
| | - J Sivaraman
- Department of Biological Sciences; National University of Singapore; Singapore
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15
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Huang F, Wang J, Qu A, Shen L, Liu J, Liu J, Zhang Z, An Y, Shi L. Maintenance of Amyloid β Peptide Homeostasis by Artificial Chaperones Based on Mixed-Shell Polymeric Micelles. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201400735] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Huang F, Wang J, Qu A, Shen L, Liu J, Liu J, Zhang Z, An Y, Shi L. Maintenance of Amyloid β Peptide Homeostasis by Artificial Chaperones Based on Mixed-Shell Polymeric Micelles. Angew Chem Int Ed Engl 2014; 53:8985-90. [DOI: 10.1002/anie.201400735] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/20/2014] [Indexed: 01/14/2023]
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17
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Mereuta L, Roy M, Asandei A, Lee JK, Park Y, Andricioaei I, Luchian T. Slowing down single-molecule trafficking through a protein nanopore reveals intermediates for peptide translocation. Sci Rep 2014; 4:3885. [PMID: 24463372 PMCID: PMC3902492 DOI: 10.1038/srep03885] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 12/19/2013] [Indexed: 12/20/2022] Open
Abstract
The microscopic details of how peptides translocate one at a time through nanopores are crucial determinants for transport through membrane pores and important in developing nano-technologies. To date, the translocation process has been too fast relative to the resolution of the single molecule techniques that sought to detect its milestones. Using pH-tuned single-molecule electrophysiology and molecular dynamics simulations, we demonstrate how peptide passage through the α-hemolysin protein can be sufficiently slowed down to observe intermediate single-peptide sub-states associated to distinct structural milestones along the pore, and how to control residence time, direction and the sequence of spatio-temporal state-to-state dynamics of a single peptide. Molecular dynamics simulations of peptide translocation reveal the time- dependent ordering of intermediate structures of the translocating peptide inside the pore at atomic resolution. Calculations of the expected current ratios of the different pore-blocking microstates and their time sequencing are in accord with the recorded current traces.
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Affiliation(s)
- Loredana Mereuta
- Department of Physics, Alexandru I. Cuza University, Iasi, Romania
- These authors contributed equally to this work
| | - Mahua Roy
- Department of Chemistry, University of California, Irvine CA 92697, USA
- These authors contributed equally to this work
| | - Alina Asandei
- Department of Interdisciplinary Research, Alexandru I. Cuza University, Iasi, Romania
| | - Jong Kook Lee
- Research Center for Proteineous Materials, Chosun University, Gwangju, South Korea
| | - Yoonkyung Park
- Research Center for Proteineous Materials, Chosun University, Gwangju, South Korea
| | - Ioan Andricioaei
- Department of Chemistry, University of California, Irvine CA 92697, USA
| | - Tudor Luchian
- Department of Physics, Alexandru I. Cuza University, Iasi, Romania
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18
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19
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Loureiro JA, Rocha S, Pereira MDC. Charged surfactants induce a non-fibrillar aggregation pathway of amyloid-beta peptide. J Pept Sci 2013; 19:581-7. [PMID: 23922329 DOI: 10.1002/psc.2535] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 05/30/2013] [Accepted: 06/17/2013] [Indexed: 01/21/2023]
Abstract
The amyloid β-peptide with a sequence of 42 amino acids is the major constituent of extracellular amyloid deposits in Alzheimer's disease plaques. The control of the peptide self-assembly is difficult to achieve because the process is fast and is affected by many variables. In this paper, we describe the effect of different charged and non-charged surfactants on Aβ(₁₋₄₂) fibrillation to define common alternate aggregation pathways. The characterization of the peptide-surfactant interactions by ultra-structural analysis, thioflavin T assay and secondary structure analysis, suggested that charged surfactants interact with Aβ(₁₋₄₂) through electrostatic interactions. Charged micelles slow down the aggregation process and stabilize the peptide in the oligomeric state, whereas non-charged surfactants promote the Aβ(₁₋₄₂) fibril formation.
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Affiliation(s)
- Joana A Loureiro
- LEPAE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Roberto Frias, Porto, Portugal
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20
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Pandey NK, Ghosh S, Dasgupta S. Effect of surfactants on preformed fibrils of human serum albumin. Int J Biol Macromol 2013; 59:39-45. [DOI: 10.1016/j.ijbiomac.2013.04.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 04/08/2013] [Accepted: 04/08/2013] [Indexed: 11/25/2022]
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21
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He C, Han Y, Fan Y, Deng M, Wang Y. Self-assembly of Aβ-based peptide amphiphiles with double hydrophobic chains. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:3391-3396. [PMID: 22272929 DOI: 10.1021/la2046146] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Two peptide-amphiphiles (PAs), 2C(12)-Lys-Aβ(12-17) and C(12)-Aβ(11-17)-C(12), were constructed with two alkyl chains attached to a key fragment of amyloid β-peptide (Aβ(11-17)) at different positions. The two alkyl chains of 2C(12)-Lys-Aβ(12-17) were attached to the same terminus of Aβ(12-17), while the two alkyl chains of C(12)-Aβ(11-17)-C(12) were separately attached to each terminus of Aβ(11-17). The self-assembly behavior of both the PAs in aqueous solutions was studied at 25 °C and at pHs 3.0, 4.5, 8.5, and 11.0, focusing on the effects of the attached positions of hydrophobic chains to Aβ(11-17) and the net charge quantity of the Aβ(11-17) headgroup. Cryogenic transmission electron microscopy and atomic force microscopy show that 2C(12)-Lys-Aβ(12-17) self-assembles into long stable fibrils over the entire pH range, while C(12)-Aβ(11-17)-C(12) forms short twisted ribbons and lamellae by adjusting pHs. The above fibrils, ribbons, and lamellae are generated by the lateral association of nanofibrils. Circular dichroism spectroscopy suggests the formation of β-sheet structure with twist and disorder to different extents in the aggregates of both the PAs. Some of the C(12)-Aβ(11-17)-C(12) molecules adopt turn conformation with the weakly charged peptide sequence, and the Fourier transform infrared spectroscopy indicates that the turn content increases with the pH increase. This work provides additional basis for the manipulations of the PA's nanostructures and will lead to the development of tunable nanostructure materials.
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Affiliation(s)
- Chengqian He
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
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22
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Wang M, Jiji RD. Spectroscopic detection of β -sheet structure in nascent Aβ oligomers. JOURNAL OF BIOPHOTONICS 2011; 4:637-44. [PMID: 21702084 DOI: 10.1002/jbio.201100023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 05/13/2011] [Accepted: 06/06/2011] [Indexed: 05/12/2023]
Abstract
Deep-UV resonance Raman (UVRR) spectroscopy and circular dichroism (CD) were employed to study the secondary structure of Aβ(1-42) in fresh samples with increasing fractions of oligomeric peptide. A feature with a minimum at ~217 nm appeared in CD spectra of samples containing oligomeric Aβ(1-42). UVRR spectra more closely resembled those of disordered proteins. The primary difference between UVRR spectra was the ratio of the 1236 cm(-1) to 1260 cm(-1) amide III peak intensities, which shifted in favor of the 1236 cm(-1) band as the fraction of oligomeric peptide increased.
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Affiliation(s)
- Mingjuan Wang
- University of Missouri-Columbia, Department of Chemistry, Columbia, Missouri 65211, USA.
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23
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Wang Q, Shah N, Zhao J, Wang C, Zhao C, Liu L, Li L, Zhou F, Zheng J. Structural, morphological, and kinetic studies of β-amyloid peptide aggregation on self-assembled monolayers. Phys Chem Chem Phys 2011; 13:15200-10. [PMID: 21769359 DOI: 10.1039/c1cp21156k] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The misfolding and aggregation of β-amyloid peptides (Aβ) into amyloid fibrils, a process that has been pathologically linked to the onset of Alzheimer's disease, is dependent on the presence of a heterogeneous surface (e.g., cell membrane). Understanding of the kinetics of amyloid fibril formation and associated structural transition from monomers to intermediates and eventually to fibrils is critical for the development of viable therapeutic agents. In this work, using circular dichroism (CD), atomic force microscopy (AFM), surface plasmon resonance (SPR), and molecular dynamics (MD) simulations, we studied the adsorption, aggregation, and conformational changes of Aβ(1-42) from fresh monomers to fully grown fibrils on four model self-assembled monolayers (SAMs): hydrophobic CH(3)-terminated SAM, hydrophilic OH-terminated SAM, negatively charged COOH-terminated SAMs, and positively charged NH(2)-terminated SAM. The seeding effect of Aβ(1-42) on the kinetics of Aβ aggregation on different SAMs is also examined. The CD, AFM, and SPR data show that all of these SAMs greatly accelerate the formation of β-sheets and amyloid fibrils through surface-enhanced interactions, but Aβ(1-42) peptides preferentially adsorb on a hydrophobic CH(3)-SAM and a positively charged NH(2)-SAM with much stronger interactions than on a hydrophilic OH-SAM and a negatively charged COOH-SAM. MD simulations further reveal that hydrophobic interactions present a general driving force for Aβ adsorption on all SAMs. As Aβ aggregates grow into larger species by packing hydrophobic C-terminals to form a hydrophobic core while exposing hydrophilic and negatively charged N-terminals to solution, electrostatic interactions become more strengthened when they interact with the SAMs especially for the COOH-SAM and the NH(2)-SAM. Thus, both hydrophobic and electrostatic interactions contribute differently to different Aβ-SAM systems and to different aggregation stages. A postulated mechanism is proposed to describe the structure and kinetics of Aβ aggregation from aqueous solution to the SAMs, providing valuable insights into Aβ aggregation on biological cell membranes.
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Affiliation(s)
- Qiuming Wang
- Department of Chemical and Biomolecular Engineering, University of Akron, Akron, Ohio 44325, USA
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24
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Ye M, Zhang Y, Li H, Xie M, Hu J. Supramolecular Structures of Amyloid-Related Peptides in an Ambient Water Nanofilm. J Phys Chem B 2010; 114:15759-65. [PMID: 21077660 DOI: 10.1021/jp105501x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ming Ye
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yi Zhang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
| | - Hai Li
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
| | - Muyun Xie
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Hu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
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25
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Effect of trehalose on the interaction of Alzheimer's Aβ-peptide and anionic lipid monolayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:26-33. [PMID: 20920466 DOI: 10.1016/j.bbamem.2010.09.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2009] [Revised: 09/26/2010] [Accepted: 09/29/2010] [Indexed: 01/07/2023]
Abstract
The interaction of amyloid β-peptide (Aβ) with cell membranes is believed to play a central role in the pathogenesis of Alzheimer's disease. In particular, recent experimental evidence indicates that bilayer and monolayer membranes accelerate the aggregation and amyloid fibril formation rate of Aβ. Understanding that interaction could help develop therapeutic strategies for treatment of the disease. Trehalose, a disaccharide of glucose, has been shown to be effective in preventing the aggregation of numerous proteins. It has also been shown to delay the onset of certain amyloid-related diseases in a mouse model. Using Langmuir monolayers and molecular simulations of the corresponding system, we study several thermodynamic and kinetic aspects of the insertion of Aβ peptide into DPPG monolayers in water and trehalose subphases. In the water subphase, the insertion of the Aβ peptide into the monolayer exhibits a lag time which decreases with increasing temperature of the subphase. In the presence of trehalose, the lag time is completely eliminated and peptide insertion is completed within a shorter time period compared to that observed in pure water. Molecular simulations show that more peptide is inserted into the monolayer in the water subphase, and that such insertion is deeper. The peptide at the monolayer interface orients itself parallel to the monolayer, while it inserts with an angle of 50° in the trehalose subphase. Simulations also show that trehalose reduces the conformational change that the peptide undergoes when it inserts into the monolayer. This observation helps explain the experimentally observed elimination of the lag time by trehalose and the temperature dependence of the lag time in the water subphase.
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26
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Hung YT, Lin MS, Chen WY, Wang SSS. Investigating the effects of sodium dodecyl sulfate on the aggregative behavior of hen egg-white lysozyme at acidic pH. Colloids Surf B Biointerfaces 2010; 81:141-51. [PMID: 20674294 DOI: 10.1016/j.colsurfb.2010.07.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2010] [Revised: 07/03/2010] [Accepted: 07/03/2010] [Indexed: 11/30/2022]
Abstract
The research presented here is aimed at examining the effects of sodium dodecyl sulfate on the aggregative behavior of hen egg-white lysozyme at pH 2.0. Through various spectroscopic techniques, dynamic light scattering, and electron microscopy, we first demonstrated that SDS exhibited a biphasic effect on lysozyme fibrillation. The presence of SDS at higher concentrations (e.g., 0.25, 5.00, or 20.00 mM SDS) was found to suppress fibril formation of lysozyme whereas fibrillogenic lysozyme-SDS ensemble containing beta-sheet-rich conformation was observed upon the addition of lower concentrations of SDS (e.g., 0.00, 0.06, or 0.1mM SDS). Next, our equilibrium urea-unfolding data revealed that lysozyme samples with higher SDS concentrations showed superior thermodynamic stabilities over the ones with no or lower levels of SDS. Finally, the correlation between SDS concentration and lysozyme aggregative/fibrillogenic propensity and the underlying interacting mechanism were further explored using surface tensiometry and isothermal titration calorimetry. We believe the outcome from this work may not only help decipher the molecular mechanism of amyloid fibrillation, but also shed light on a rational design of potential therapeutic strategies for amyloid pathology.
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Affiliation(s)
- Ying-Tz Hung
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
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27
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Wang SSS, Liu KN, Han TC. Amyloid fibrillation and cytotoxicity of insulin are inhibited by the amphiphilic surfactants. Biochim Biophys Acta Mol Basis Dis 2010; 1802:519-30. [PMID: 20176106 DOI: 10.1016/j.bbadis.2010.02.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 01/30/2010] [Accepted: 02/16/2010] [Indexed: 11/26/2022]
Abstract
Amyloid fibrils have been associated with at least 25 different degenerative diseases. The 51-residue polypeptide hormone insulin, which is associated with type II diabetes, has been shown to self-assemble to form amyloid fibrils in vitro. With bovine insulin as a model, the research presented here explores the effects of two amphiphilic surfactants (1,2-dihexanoyl-sn-glycero-3-phosphocholine (di-C7-PC) and 1,2-diheptanoyl-sn-glycero-3-phosphocholine (di-C7-PC)) on the in vitro fibrillation process of bovine insulin at pH 2.0 and 55 degrees C. We demonstrated that insulin fibrillation may be inhibited by both surfactants in a dose-dependent fashion. The best inhibition of fibril formation is observed when insulin is incubated with 4mM di-C7-PC. Moreover, the addition of either surfactant at the concentrations studied attenuated insulin fibril-induced cytotoxicity in both PC12 and SH-SY5Y cell lines. The results from this work may contribute to the understanding of the molecular factors affecting amyloid fibrillation and the molecular mechanism(s) of the interactions between the membrane and amyloid proteins.
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Affiliation(s)
- Steven S-S Wang
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
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28
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On the metal ion (Zn2+, Cu2+) coordination with beta-amyloid peptide: DFT computational study. Interdiscip Sci 2010; 2:57-69. [DOI: 10.1007/s12539-010-0086-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 11/10/2009] [Accepted: 11/11/2009] [Indexed: 01/02/2023]
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29
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Jiang D, Dinh KL, Ruthenburg TC, Zhang Y, Su L, Land DP, Zhou F. A kinetic model for beta-amyloid adsorption at the air/solution interface and its implication to the beta-amyloid aggregation process. J Phys Chem B 2009; 113:3160-8. [PMID: 19260715 DOI: 10.1021/jp8085792] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
At the air/buffer solution interface the kinetics of adsorption of amyloid beta peptide, Abeta(1-42), whose bulk concentration (submicromolar) is more than 2 orders of magnitude lower than that typically used in other in vitro aggregation studies, has been studied using a Langmuir-Blodgett trough. The pressure-time curves exhibit a lag phase, wherein the surface pressure essentially remains at zero, and a rising phase, corresponding to the Abeta adsorption at the interface. The duration of the lag phase was found to be highly dependent on both the Abeta bulk concentration and the solution temperature. A large activation energy (62.2 +/- 4.1 KJ/mol) was determined and the apparent adsorption rate constant was found to be linearly dependent on the Abeta bulk concentration. Attenuated total reflection-IR spectra of the adsorbed Abeta transferred to a solid substrate and circular dichroism measurements of Abeta in the solution layer near the interface reveal that the natively unstructured Abeta in the bulk undergo a conformation change (folding) to mainly the alpha-helical structure. The results suggest that, prior to the adsorption step, an equilibrium between Abeta conformations is established within the subsurface. The kinetic equation derived from this model confirms that the overall Abeta adsorption is kinetically controlled and the apparent rate constant is proportional to the Abeta bulk concentration. This model also indicates that interfaces such as cell membranes and lipid bilayers may facilitate Abeta aggregation/ fibrillation by providing a thin hydrophobic layer adjacent to the interface for the initial A/beta conformation change (misfolding) and accumulation. Such a preconcentration effect offers a plausible explanation of the fact that Abeta fibrillation occurs in vivo at nanomolar concentrations. Another important biological implication from our work is that Abeta misfolding may occur before its adsorption onto a cell membrane. This general kinetic model should also find applications in adsorption studies of other types of biomolecules whose overall kinetics exhibits a lag phase that is dependent on the bulk concentration of the adsorbate.
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Affiliation(s)
- Dianlu Jiang
- Department of Chemistry and Biochemistry, California State University, Los Angeles, Los Angeles, California 90032, USA
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30
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Park YH, Kim YJ, Son IH, Yang HD. Inhibition of beta-amyloid(1-40) Peptide Aggregation and Neurotoxicity by Citrate. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2009; 13:273-9. [PMID: 19885010 DOI: 10.4196/kjpp.2009.13.4.273] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 07/31/2009] [Accepted: 08/17/2009] [Indexed: 11/15/2022]
Abstract
The accumulation of beta-amyloid (Abeta) aggregates is a characteristic of Alzheimer's disease (AD). Furthermore, these aggregates have neurotoxic effects on cells, and thus, molecules that inhibit Abeta aggregate formation could be valuable therapeutics for AD. It is well known that aggregation of Abeta depends on its hydrophobicity, and thus, in order to increase the hydrophilicity of Abeta, we considered using citrate, an anionic surfactant with three carboxylic acid groups. We hypothesized that citrate could reduce hydrophobicity and increase hydrophilicity of Abeta(1-40) molecules via hydrophilic/electrostatic interactions. We found that citrate significantly inhibited Abeta(1-40) aggregation and significantly protected SH-SY5Y cell line against Abeta(1-40) aggregates-induced neurotoxicity. In details, we examined the effects of citrate on Abeta(1-40) aggregation and on Abeta(1-40) aggregates-induced cytotoxicity, cell viability, and apoptosis. Th-T assays showed that citrate significantly inhibited Abeta(1-40) aggregation in a concentration-dependent manner (Th-T intensity: from 91.3% in 0.01 mM citrate to 82.1% in 1.0 mM citrate vs. 100.0% in Abeta(1-40) alone). In cytotoxicity and viability assays, citrate reduced the toxicity of Abeta(1-40) in a concentration-dependent manner, in which the cytotoxicity decreased from 107.5 to 102.3% as compared with Abeta(1-40) aggregates alone treated cells (127.3%) and the cell viability increased from 84.6 to 93.8% as compared with the Abeta(1-40) aggregates alone treated cells (65.3%). Furthermore, Hoechst 33342 staining showed that citrate (1.0 mM) suppressed Abeta(1-40) aggregates-induced apoptosis in the cells. This study suggests that citrate can inhibit Abeta(1-40) aggregation and protect neurons from the apoptotic effects of Abeta(1-40) aggregates. Accordingly, our findings suggest that citrate administration should be viewed as a novel neuroprotective strategy for AD.
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Affiliation(s)
- Yong Hoon Park
- Inam Neuroscience Research Center, Sanbon Medical Center, College of Medicine, Wonkwang University, Gunpo 435-040, Korea
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31
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Deng M, Yu D, Hou Y, Wang Y. Self-assembly of Peptide−Amphiphile C12−Aβ(11−17) into Nanofibrils. J Phys Chem B 2009; 113:8539-44. [DOI: 10.1021/jp904289y] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Manli Deng
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Defeng Yu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Yanbo Hou
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Yilin Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
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32
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Talmard C, Leuma Yona R, Faller P. Mechanism of zinc(II)-promoted amyloid formation: zinc(II) binding facilitates the transition from the partially alpha-helical conformer to aggregates of amyloid beta protein(1-28). J Biol Inorg Chem 2008; 14:449-55. [PMID: 19083027 DOI: 10.1007/s00775-008-0461-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Accepted: 11/30/2008] [Indexed: 10/21/2022]
Abstract
The amyloidoses are a group of disorders characterized by aberrant protein folding and assembly, leading to the deposition of insoluble protein fibrils (amyloid), which provokes cell dysfunction and later cell death. One of the physiologically relevant environmental factors able to affect the conformation and hence the aggregation properties of amyloidogenic proteins/peptides is metal ions. Zn(II) promotes aggregation of most amyloidogenic peptides/proteins in vitro, including amyloid beta protein (Abeta), but the underlying mechanism is not known. To better understand this mechanism the present study focused on the partially alpha-helical conformer, supposed to be an intermediate in Abeta aggregation. This partially alpha-helical conformer is stabilized by 10-20% 2,2,2-trifluoroethanol (TFE): therefore, the influence of Zn binding on the aggregation of the amylidogenic model peptide Abeta(1-28) (Abeta28) was investigated at different TFE concentrations. The results showed a synergistic effect of Zn(II) and 10% TFE, i.e., that either Zn or 10% TFE accelerated Abeta28 aggregation on its own, but with them together an at least 10 times promotion of Abeta28 aggregation was observed. Further studies by thioflavin T fluorescence spectroscopy, transmission electron microscopy, and circular dichroism (CD) spectroscopy suggested that the aggregates of Zn-Abeta28 formed in 10%TFE contain a beta-sheet secondary structure and are more of the amyloid type. CD spectroscopy indicated that Zn binding disrupted partially the alpha-helical structure of Abeta28 in TFE. Thus, we propose that the promotion of Abeta28 aggregation by Zn is based on the transformation of the partially alpha-helical conformer (intermediate) towards the beta-sheet amyloid structure by a destabilization of the alpha-helix in the intermediate.
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33
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Han Y, Huang X, Cao M, Wang Y. Micellization of Surfactin and Its Effect on the Aggregate Conformation of Amyloid β(1-40). J Phys Chem B 2008; 112:15195-201. [DOI: 10.1021/jp805966x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Yuchun Han
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Xu Huang
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Meiwen Cao
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Yilin Wang
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
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34
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Sambasivam D, Liu CW, Jayaraman M, Malar EP, Rajadas J. Aggregation and conformational studies on a pentapeptide derivative. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:1659-67. [DOI: 10.1016/j.bbapap.2008.07.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 06/21/2008] [Accepted: 07/21/2008] [Indexed: 10/21/2022]
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35
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Rodziewicz-Motowidło S, Czaplewska P, Sikorska E, Spodzieja M, Kołodziejczyk AS. The Arctic mutation alters helix length and type in the 11-28 beta-amyloid peptide monomer-CD, NMR and MD studies in an SDS micelle. J Struct Biol 2008; 164:199-209. [PMID: 18765285 DOI: 10.1016/j.jsb.2008.07.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 07/11/2008] [Accepted: 07/29/2008] [Indexed: 11/30/2022]
Abstract
The beta-amyloid (Abeta) is the major peptide constituent of neuritic plaques in Alzheimer's disease, and its aggregation is believed to play a central role in the pathogenesis of the disease. Naturally occurring mutations resulting in changes in the Abeta sequence (pos. 21-23) are associated with familial Alzheimer's-like diseases with extensive cerebrovascular pathology. It has been demonstrated that such mutations alter the aggregation ability of Abeta and its neurotoxicity. Among the five mutations at positions 21-23 there is one with distinct clinical characteristics and a potentially distinct pathogenic mechanism-the Arctic (E22G) mutation. We have examined the structures of fragment 11-28 of the native peptide and its E22G variant. This fragment was chosen because it has been shown to be a good model for conformational and aggregation studies as it contains the hydrophobic core responsible for aggregation and the residues critical to alpha-secretase cleavage of APP. The detailed structure of the two peptides was determined using CD, 2D NMR and molecular dynamics techniques under water-SDS micelle conditions. Our studies indicated the existence of partially alpha- and 3(10)-helical conformations in the native and mutated peptide, respectively.
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36
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Valerio M, Porcelli F, Zbilut JP, Giuliani A, Manetti C, Conti F. pH effects on the conformational preferences of amyloid beta-peptide (1-40) in HFIP aqueous solution by NMR spectroscopy. ChemMedChem 2008; 3:833-43. [PMID: 18228239 DOI: 10.1002/cmdc.200700324] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The structure and aggregation state of amyloid beta-peptide (Abeta) in membrane-like environments are important determinants of pathological events in Alzheimer's disease. In fact, the neurotoxic nature of amyloid-forming peptides and proteins is associated with specific conformational transitions proximal to the membrane. Under certain conditions, the Abeta peptide undergoes a conformational change that brings the peptide in solution to a "competent state" for aggregation. Conversion can be obtained at medium pH (5.0-6.0), and in vivo this appears to take place in the endocytic pathway. The combined use of (1)H NMR spectroscopy and molecular dynamics-simulated annealing calculations in aqueous hexafluoroisopropanol simulating the membrane environment, at different pH conditions, enabled us to get some insights into the aggregation process of Abeta, confirming our previous hypotheses of a relationship between conformational flexibility and aggregation propensity. The conformational space of the peptide was explored by means of an innovative use of principal component analysis as applied to residue-by-residue root-mean-square deviations values from a reference structure. This procedure allowed us to identify the aggregation-prone regions of the peptide.
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Affiliation(s)
- Mariacristina Valerio
- Dipartimento di Chimica, Università La Sapienza, Piazzale Aldo Moro 5, 00185 Roma, Italia
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37
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Sakuragi M, Takeda Y, Shimada N, Sakurai K. Entrapment of Immature Amyloid Protofilaments in the Hydrophobic Domain of Schizophyllan. Polym Bull (Berl) 2008. [DOI: 10.1007/s00289-008-0927-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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38
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Cao M, Han Y, Wang J, Wang Y. Modulation of Fibrillogenesis of Amyloid β(1−40) Peptide with Cationic Gemini Surfactant. J Phys Chem B 2007; 111:13436-43. [DOI: 10.1021/jp075271b] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Meiwen Cao
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
| | - Yuchun Han
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
| | - Jinben Wang
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
| | - Yilin Wang
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
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39
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Rodziewicz-Motowidło S, Juszczyk P, Kołodziejczyk AS, Sikorska E, Skwierawska A, Oleszczuk M, Grzonka Z. Conformational solution studies of the SDS micelle-bound 11-28 fragment of two Alzheimer's β-amyloid variants (E22K and A21G) using CD, NMR, and MD techniques. Biopolymers 2007; 87:23-39. [PMID: 17534931 DOI: 10.1002/bip.20768] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The beta-amyloid (Abeta) is the major peptide constituent of neuritic plaques in Alzheimer's disease (AD) and its aggregation is believed to play a central role in the pathogenesis of the disease. Naturally occurring mutations resulting in changes in the Abeta sequence (pos. 21-23) are associated with familial AD-like diseases with extensive cerebrovascular pathology. It was proved that the mutations alter the aggregation ability of Abeta and its neurotoxicity. Among five mutations at positions 21-23 there are two mutations with distinct clinical characteristics and potentially distinct pathogenic mechanism-the Italian (E22K) and the Flemish (A21G) mutations. In our studies we have examined the structures of the 11-28 fragment of the Italian and Flemish Abeta variants. The fragment was chosen because it has been shown to be the most important for amyloid fibril formation. The detailed structure of both variants Abeta(11-28) was determined using CD, 2D NMR, and molecular dynamics techniques under water-SDS micelle conditions. The NMR analysis revealed two distinct sets of proton resonances for the peptides. The studies of both peptides pointed out the existence of well-defined alpha-helical conformation in the Italian mutant, whereas the Flemish was found to be unstructured with the possibility of a bent structure in the central part of the peptide.
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40
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Wang SSS, Chen PH, Hung YT. Effects of p-benzoquinone and melatonin on amyloid fibrillogenesis of hen egg-white lysozyme. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.molcatb.2006.06.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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41
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Abu-Baker S, Lorigan GA. Phospholamban and its phosphorylated form interact differently with lipid bilayers: a 31P, 2H, and 13C solid-state NMR spectroscopic study. Biochemistry 2006; 45:13312-22. [PMID: 17073452 PMCID: PMC2586141 DOI: 10.1021/bi0614028] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phospholamban (PLB) is a 52-amino acid integral membrane protein that helps to regulate the flow of Ca(2+) ions in cardiac muscle cells. Recent structural studies on the PLB pentamer and the functionally active monomer (AFA-PLB) debate whether its cytoplasmic domain, in either the phosphorylated or dephosphorylated states, is alpha-helical in structure as well as whether it associates with the lipid head groups (Oxenoid, K. (2005) Proc. Natl. Acad. Sci. U.S.A. 102, 10870-10875; Karim, C. B. (2004) Proc. Natl. Acad. Sci. U.S.A. 101, 14437-14442; Andronesi, C.A. (2005) J. Am. Chem. Soc. 127, 12965-12974; Li, J. (2003) Biochemistry 42, 10674-10682; Metcalfe, E. E. (2005) Biochemistry 44, 4386-4396: Clayton, J. C. (2005) Biochemistry 44, 17016-17026). Comparing the secondary structure of the PLB pentamer and its phosphorylated form (P-PLB) as well as their interaction with the lipid bilayer is crucial in order to understand its regulatory function. Therefore, in this study, the full-length wild-type (WT) PLB and P-PLB were incorporated into 1-palmitoyl-2-oleoyl-sn-glycero-phosphocholine (POPC) phospholipid bilayers and studied utilizing solid-state NMR spectroscopy. The analysis of the (2)H and (31)P solid-state NMR data of PLB and P-PLB in POPC multilamellar vesicles (MLVs) indicates that a direct interaction takes place between both proteins and the phospholipid head groups. However, the interaction of P-PLB with POPC bilayers was less significant compared that with PLB. Moreover, the secondary structure using (13)C=O site-specific isotopically labeled Ala15-PLB and Ala15-P-PLB in POPC bilayers suggests that this residue, located in the cytoplasmic domain, is a part of an alpha-helical structure for both PLB and P-PLB.
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Affiliation(s)
- Shadi Abu-Baker
- Department of Chemistry and Biochemistry Miami University, Oxford, Ohio 45056
| | - Gary A. Lorigan
- Department of Chemistry and Biochemistry Miami University, Oxford, Ohio 45056
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42
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Li Y, Cao M, Wang Y. Alzheimer Amyloid β(1−40) Peptide: Interactions with Cationic Gemini and Single-Chain Surfactants. J Phys Chem B 2006; 110:18040-5. [PMID: 16956295 DOI: 10.1021/jp063176h] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aggregation of amyloid beta-peptide [Abeta(1-40)] into fibril is a key pathological process associated with Alzheimer's disease. The effect of cationic gemini surfactant hexamethylene-1,6-bis-(dodecyldimethylammonium bromide) [C(12)H(25)(CH(3))(2)N(CH(2))(6)N(CH(3))(2)C(12)H(25)]Br(2) (designated as C(12)C(6)C(12)Br(2)) and single-chain cationic surfactant dodecyltrimethylammonium bromide (DTAB) on the Alzheimer amyloid beta-peptide Abeta(1-40) aggregation behavior was studied by microcalorimetry, circular dichroism (CD), and atomic force microscopy (AFM) measurements at pH 7.4. Without addition of surfactant, 0.5 g/L Abeta(1-40) mainly exists in dimeric state. It is found that the addition of the monomers of C(12)C(6)C(12)Br(2) and DTAB may cause the rapid aggregation of Abeta(1-40) and the fibrillar structures are observed by CD spectra and the AFM images. Due to the repulsive interaction among the head groups of surfactants and the formation of a small hydrophobic cluster of surfactant molecules, the fibrillar structure is disrupted again as the surfactant monomer concentration is increased, whereas globular species are observed in the presence of micellar solution. Different from single-chain surfactant, C(12)C(6)C(12)Br(2) has a much stronger interaction with Abeta(1-40) to generate larger endothermic energy at much lower surfactant concentration and has much stronger ability to induce the aggregation of Abeta(1-40).
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Affiliation(s)
- Yajuan Li
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, Peoples Republic of China
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43
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Mandal PK, Pettegrew JW, McKeag DW, Mandal R. Alzheimer’s Disease: Halothane Induces Aβ Peptide to Oligomeric Form—Solution NMR Studies. Neurochem Res 2006; 31:883-90. [PMID: 16807784 DOI: 10.1007/s11064-006-9092-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2006] [Indexed: 11/25/2022]
Abstract
Alzheimer's disease (AD) is a significant contributor to cognitive decline and is responsible for about half of the cases of dementia in later life. Although exact etiology of AD is not known, however, many risk factors for AD are identified. Anesthesia for elderly patients is considered as a risk factor in AD as they frequently experience deterioration in cognitive function with long exposure to anesthetics during surgery. Inhaled anesthetic agents remain the mainstay for patients undergoing major surgical operations. This study using multidimensional NMR spectroscopy provides the first direct evidence in vitro that inhaled anesthetic, halothane specifically interacts with Abeta40 and Abeta42 peptide. Halothane induces structural alternation of Abeta peptide from soluble monomeric alpha-helical form to oligomeric beta-sheet conformation, which may hasten the onset of AD. Abeta42 is more prone to oligomerization compared to Abeta40 in the presence of halothane. The molecular mechanism of halothane induced structural alternation of Abeta peptide is discussed.
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Affiliation(s)
- Pravat K Mandal
- Western Psychiatric Institute and Clinic Department of Psychiatry, University of Pittsburgh Medical School, 3811 O'Hara Street, PA 15213, USA.
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44
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Zirah S, Kozin SA, Mazur AK, Blond A, Cheminant M, Ségalas-Milazzo I, Debey P, Rebuffat S. Structural changes of region 1-16 of the Alzheimer disease amyloid beta-peptide upon zinc binding and in vitro aging. J Biol Chem 2005; 281:2151-61. [PMID: 16301322 DOI: 10.1074/jbc.m504454200] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Amyloid deposits within the cerebral tissue constitute a characteristic lesion associated with Alzheimer disease. They mainly consist of the amyloid peptide Abeta and display an abnormal content in Zn(2+) ions, together with many truncated, isomerized, and racemized forms of Abeta. The region 1-16 of Abeta can be considered the minimal zinc-binding domain and contains two aspartates subject to protein aging. The influence of zinc binding and protein aging related modifications on the conformation of this region of Abeta is of importance given the potentiality of this domain to constitute a therapeutic target, especially for immunization approaches. In this study, we determined from NMR data the solution structure of the Abeta-(1-16)-Zn(2+) complex in aqueous solution at pH 6.5. The residues His(6), His(13), and His(14) and the Glu(11) carboxylate were identified as ligands that tetrahedrally coordinate the Zn(II) cation. In vitro aging experiments on Abeta-(1-16) led to the formation of truncated and isomerized species. The major isomer generated, Abeta-(1-16)-l-iso-Asp(7), displayed a local conformational change in the His(6)-Ser(8) region but kept a zinc binding propensity via a coordination mode involving l-iso-Asp(7). These results are discussed here with regard to Abeta fibrillogenesis and the potentiality of the region 1-16 of Abeta to be used as a therapeutic target.
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Affiliation(s)
- Séverine Zirah
- Laboratoire de Chimie et Biochimie des Substances Naturelles, UMR 5154 CNRS-MNHN, Département Régulations, Développement et Diversité Moléculaire, Muséum National d'Histoire Naturelle, 63 Rue Buffon, 75005 Paris, France
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45
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Wang SSS, Chen YT, Chou SW. Inhibition of amyloid fibril formation of β-amyloid peptides via the amphiphilic surfactants. Biochim Biophys Acta Mol Basis Dis 2005; 1741:307-13. [PMID: 15994066 DOI: 10.1016/j.bbadis.2005.05.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 05/27/2005] [Accepted: 05/31/2005] [Indexed: 11/15/2022]
Abstract
Beta-amyloid peptide (A beta) is the major proteinacious constituent of senile plaques in Alzheimer's disease and is believed to be responsible for the neurodegeneration process associated with the disease. While the actual size of the aggregated species responsible for A beta neurotoxicity and fibrillogenesis mechanism(s) remain unknown, retardation of A beta aggregation still holds assurance as an effective strategy in reducing A beta-elicited toxicity. The research presented here is aimed at examining the inhibitory effect of two amphiphilic surfactants, di-C6-PC and di-C7-PC, on the in vitro fibrillogenesis process of A beta(1--40) peptides at physiological pH (pH 7.2). Using ThT-induced fluorescence, turbidity, Congo red binding, and circular dichroism spectroscopy studies, our research demonstrated that the inhibition of A beta(1--40) fibril formation was di-C6-PC and di-C7-PC concentration-dependent. The best inhibitory action on fibril formation was observed when A beta was incubated with di-C7-PC at 100 microM over time. We believe that the outcome from this work will aid in the development and/or design of potential inhibitory agents against amyloid formation associated with Alzheimer's and other amyloid diseases.
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Affiliation(s)
- Steven S-S Wang
- Department of Chemical Engineering, National Taiwan University, No.1, Sec.4, Roosevelt Road, Taipei 10617, Taiwan.
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46
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Sabaté R, Estelrich J. Stimulatory and inhibitory effects of alkyl bromide surfactants on beta-amyloid fibrillogenesis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:6944-9. [PMID: 16008407 DOI: 10.1021/la050472x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Beta-amyloid peptide (Abeta), in fibrillar form, is the primary constituent of senile plaques, a defining feature of Alzheimer's disease. In solution assays, fibril formation exhibits a lag time, interpreted as a nucleation/condensation-dependent process. The kinetics of fibrillogenesis is controlled by two key parameters: nucleation and elongation rate constants. We characterized the time course of Abeta fibril formation by measuring the scattering caused by peptide aggregates. We report here the interaction of Abeta with three alkylammonium bromides (dodecyl, tetradecyl, and hexadecyl) at supra- and submicellar concentrations and their influence on the kinetic constants. We observed a dual behavior: surfactants promoted or retarded fibril formation in a concentration-dependent manner. Below a determined surfactant concentration (close to the corresponding critical micellar concentration in medium without peptide), surfactants favor aggregation, presumably by means of electrostatic interactions that destabilize the native conformation. Beyond such concentration, the stabilizing effects of the monomer predominate. As a general rule, surfactants delay but do not completely inhibit aggregation.
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Affiliation(s)
- Raimon Sabaté
- Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona, Barcelona (Catalonia, Spain)
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47
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Giacomelli CE, Norde W. Conformational Changes of the Amyloidβ-Peptide (1-40) Adsorbed on Solid Surfaces. Macromol Biosci 2005; 5:401-7. [PMID: 15889393 DOI: 10.1002/mabi.200400189] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The conformational change of the 39-43 residues of the amyloid beta-peptide (Abeta) toward a beta-sheet enriched state promotes self-aggregation of the peptide molecules and constitutes the major peptide component of the amyloid plaques in Alzheimer patients. The crucial question behind the self-aggregation of Abeta is related to the different pathways the peptide may take after cleavage from the amyloid precursor proteins at cellular membranes. This work is aiming at determining the conformation of the Abeta (1-40) adsorbed on hydrophobic Teflon and hydrophilic silica particles, as model sorbent surfaces mimicking the apolar transmembrane environment and the polar, charged membrane surface, respectively. The mechanism by which the Abeta interacts with solid surfaces strongly depends on the hydrophobic/hydrophilic character of the particles. Hydrophobic and electrostatic interactions contribute differently in each case, causing a completely different conformational change of the adsorbed molecules on the two surfaces. When hydrophobic interactions between the peptide and the sorbent prevail, the adsorbed Abeta (1-40) mainly adopts an alpha-helix conformation due to H-bonding in the apolar part of the peptide that is oriented towards the surface. On the other hand, when the peptide adsorbs by electrostatic interactions beta-sheet formation is promoted due to intermolecular association between the apolar parts of the adsorbed peptide. Irrespective of the characteristics of the solid sorbent, crowding the surface results in intermolecular association between adsorbed molecules leading to a strong aggregation tendency of the Abeta (1-40). [Diagram: see text] CD spectra of Abeta (1-40) at pH 7: A) in solution ([Abeta]=0.2 mg.ml(-1)) freshly prepared (line) and after overnight incubation (symbols);B) on Teflon (Gamma=0.5 mg.m(-2)).
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Affiliation(s)
- Carla E Giacomelli
- INFIQC, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Ciudad Universitaria, 5000, Córdoba, Argentina.
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48
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Mandal PK, Pettegrew JW. Alzheimer's disease: soluble oligomeric Abeta(1-40) peptide in membrane mimic environment from solution NMR and circular dichroism studies. Neurochem Res 2005; 29:2267-72. [PMID: 15672549 DOI: 10.1007/s11064-004-7035-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Amyloid beta peptide (Abeta) is a small peptide present in normal cells and aggregated Abeta is the main constituent of the extracellular amyloid plaques found in Alzheimer's disease (AD) brain. Recent studies suggest that soluble Abeta oligomers are neurotoxic rather than amyloid fibrils found in amyloid plaques. This study using multidimensional NMR spectroscopy and circular dichroism (CD) provides the first direct evidence that alterations in membrane structure can trigger the conversion of soluble alpha-helical monomeric Abeta into oligomeric Abeta in a beta-sheet conformation.
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Affiliation(s)
- Pravat K Mandal
- Neurophysics Laboratory, Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
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49
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Li F, Li H, Hu L, Kwan M, Chen G, He QY, Sun H. Structure, Assembly, and Topology of the G185R Mutant of the Fourth Transmembrane Domain of Divalent Metal Transporter. J Am Chem Soc 2005; 127:1414-23. [PMID: 15686373 DOI: 10.1021/ja047148t] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mammalian iron transporter, divalent metal transporter (DMT1), is a 12-transmembrane domain integral protein, responsible for dietary iron uptake in the duodenum and iron acquisition from transferrin in peripheral tissues. Two disease-causing mutants in animals have been found and attributed to the same missense mutation (G185R), which occurs within the putative transmembrane domain 4 (TM4) of DMT1. We have characterized a synthetic 24-mer peptide, corresponding to the sequence of the TM4 of DMT1 with G185R mutation using circular dichroism (CD) and NMR spectroscopy and show that the G185R peptide assumes mainly alpha-helical conformations in various membrane-mimetic environments. Solution structures derived from NMR and molecular dynamics/simulated annealing calculations demonstrate that the peptide exhibits a highly defined alpha-helix in its middle portion, flanked by a highly flexible N-terminus and a relatively ordered C-terminus. Both the folding and location of the C-terminus in SDS micelles are regulated by pH values. Paramagnetic broadening on peptide NMR signals by spin-labeled 5- and 16-doxylstearic acids and Mn(2+) ion suggests that both the N-terminus and the helical region of the peptide are embedded in SDS micelles. Surprisingly, self-association of the peptides for both the wild type and the G185R mutant studied by CD, electrospray ionization mass spectrometry, and NMR diffusion-ordered spectroscopy demonstrated that mutation of the Gly185 to a bulky and positively charged arginine causes a different self-assembly of the peptide, e.g., from a trimer to a hexamer, which implies that the quaternary structure of integral DMT1 may be crucial for its function in vivo.
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Affiliation(s)
- Fei Li
- Department of Chemistry and Open Laboratory of Chemical Biology, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China
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50
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Kawooya JK, Emmons TL, Gonzalez-DeWhitt PA, Camp MC, D'Andrea SC. Electrophoretic mobility of Alzheimer's amyloid-beta peptides in urea-sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Anal Biochem 2004; 323:103-13. [PMID: 14622964 DOI: 10.1016/j.ab.2003.08.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The 43-amino acid Alzheimer's amyloid-beta peptide (Abeta peptide) retains a predominantly alpha-helix and beta-strand structure in sodium dodecyl sulfate (SDS) solution. This conformer has a high tendency to aggregate during conventional SDS-polyacrylamide gel electrophoresis (PAGE). Both the secondary structure and the proclivity for aggregation are obviated by the use of urea-SDS-PAGE: In 8M urea-with or without SDS-the Abeta peptide becomes 100% random coil and remains monomeric. However, during electrophoresis in this medium, the peptide and its truncated variants do not obey the law of mass/mobility relationship that most proteins-including Abeta peptides-follow in conventional SDS-PAGE. Rather, the smaller carboxy-terminally truncated peptides migrate slower than the larger full-length peptide, while the amino terminally truncated peptide does migrate faster than the full-length Abeta peptide. Thus, despite their small size (2-4kDa) and minor differences between their lengths, the Abeta peptides display a wide separation in this low-porosity (12% acrylamide) gel. We found that this unusual electrophoretic mobility in 8M urea is due to the fact that the quantity of [35S]SDS bound to the Abeta peptides, instead of being proportional to the total number of amino acids, is rather proportional to the sum of the hydrophobicity consensus indices of the constituent amino acids. It is then their hydrophobicity and, hence, the net negative charges contributed by the peptide-bound SDS that plays a major role in determining the mobility of Abeta peptides in 8M urea-SDS-PAGE. The high selectivity of the 8M urea-SDS-PAGE method allowed us to detect the presence of hitherto unknown Abeta peptide variants that were secreted in the conditioned medium by cultured HeLa cells.
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Affiliation(s)
- John K Kawooya
- Lead Discovery Technologies--Protein Production, JR1-2201, Aventis Pharmaceuticals, 1041 Route 202-206 North, Bridgewater, NJ 08807-0800, USA.
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