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Gurtu A, Bakshi MS. Ag Nanometallic Surfaces for Self-Assembled Ordered Morphologies of Zein. ACS OMEGA 2018; 3:10851-10857. [PMID: 31459197 PMCID: PMC6645513 DOI: 10.1021/acsomega.8b02086] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 08/27/2018] [Indexed: 06/09/2023]
Abstract
Nanometallic surfaces of Ag nanoparticles (NPs) catalyzed the self-aggregation behavior of zein in different ordered morphologies such as cubes, rectangles, and bars. This was studied in a ternary in situ reaction (AgNO3 + zein + water), where zein performed the reduction as well as stabilization of Ag NPs. This reaction produced small Ag NPs of less than 10 nm predominantly bound with {111} crystal planes, which attracted the surface adsorption of zein. Surface-adsorbed zein initiated the protein seeding and converted the tertiary structure of protein into open β-pleated structure with aqueous exposed hydrophobic domains. A layered deposition of β-pleats on different crystal planes of Ag NPs derived them to nearly monodispersed cubic morphologies. The mechanistic aspects of self-aggregation of zein in the presence of nanometallic surfaces hold possible scenarios for simple and straightforward routes of protein crystallization.
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Banipal TS, Kaur G, Bakshi MS. Nanoparticle Surface Specific Adsorption of Zein and Its Self-assembled Behavior of Nanocubes Formation in Relation to On-Off SERS: Understanding Morphology Control of Protein Aggregates. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:596-607. [PMID: 26731467 DOI: 10.1021/acs.jafc.5b05495] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Zein, an industrially important protein, is characterized in terms of its food and pharmaceutical coating applications by using surface enhanced Raman spectroscopy (SERS) on Au, Ag, and PbS nanoparticles (NPs). Its specific surface adsorption behavior on Ag NPs produced self-assembled zein nanocubes which demonstrated on and off SERS activity. Both SERS characterization as well as nanocube formation of zein helped us to understand the complex protein aggregation behavior in shape controlled morphologies, a process with significant ramifications in protein crystallization to achieve ordered morphologies. Interestingly, nanocube formation was promoted in the presence of Ag rather than Au or PbS NPs under in situ synthesis and discussed in terms of specific adsorption. Zein fingerprinting was much more clear and enhanced on Au surface in comparison to Ag while PbS did not demonstrate SERS due to its semiconducting nature.
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Affiliation(s)
- Tarlok Singh Banipal
- Department of Chemistry, UGC Sponsored Center for Advanced Studies-1, Guru Nanak Dev University , Amritsar-143005, Punjab India
| | - Gurinder Kaur
- Nanotechnology Research Laboratory, College of North Atlantic , Labrador City, Newfoundland A2V 2K7 Canada
| | - Mandeep Singh Bakshi
- Department of Chemistry and Biochemistry, Wilfrid Laurier University , Science Building, 75 University Avenue West, Waterloo Ontario N2L 3C5, Canada
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Carter NA, Grove TZ. Repeat-Proteins Films Exhibit Hierarchical Anisotropic Mechanical Properties. Biomacromolecules 2015; 16:706-14. [DOI: 10.1021/bm501578j] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Nathan A. Carter
- Department of Chemistry (0212), Virginia Tech, 2107 Hahn Hall
South, Blacksburg, Virginia 24060, United States
| | - Tijana Zarkovic Grove
- Department of Chemistry (0212), Virginia Tech, 2107 Hahn Hall
South, Blacksburg, Virginia 24060, United States
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Christou K, Knorr I, Ihlemann J, Wackerbarth H, Beushausen V. Fabrication and characterization of homogeneous surface-enhanced Raman scattering substrates by single pulse UV-laser treatment of gold and silver films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:18564-18569. [PMID: 21043441 DOI: 10.1021/la103021g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The fabrication of SERS-active substrates, which offer high enhancement factors as well as spatially homogeneous distribution of the enhancement, plays an important role in the expansion of surface-enhanced Raman scattering (SERS) spectroscopy to a powerful, quantitative, and noninvasive measurement technique for analytical applications. In this paper, a novel method for the fabrication of SERS-active substrates by laser treatment of 20, 40, and 60 nm thick gold and of 40 nm thick silver films supported on quartz glass is presented. Single 308 nm UV-laser pulses were applied to melt the thin gold and silver films. During the cooling process of the noble metal, particles were formed. The particle size and density were imaged by atomic force microscopy. By varying the fluence, the size of the particles can be controlled. The enhancement factors of the nanostructures were determined by recording self-assembled monolayers of benzenethiol. The intensity of the SERS signal from benzenethiol is correlated to the mean particle size and thus to the fluence. Enhancement factors up to 10(6) with a high reproducibility were reached. Finally we have analyzed the temperature dependence of the SERS effect by recording the intensity of benzenethiol vibrations from 300 to 120 K. The temperature dependence of the SERS effect is discussed with regard to the metal properties.
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Affiliation(s)
- Konstantin Christou
- Department of Photonic Sensor Technologies, Laser-Laboratorium Göttingen e.V., Göttingen.
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Brooksby PA, Anderson KH, Downard AJ, Abell AD. Electrochemistry of ferrocenoyl beta-peptide monolayers on gold. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:1334-1339. [PMID: 19799404 DOI: 10.1021/la902402t] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The electrochemistry of self-assembled monolayers (SAMs) on gold containing a lipoic acid linker, the beta-peptide sequence (beta(3)Val-beta(3)Ala-beta(3)Leu)(n) for n = 1, 2, and a terminal ferrocenyl group has been described for the first time. Circular dichroism (CD), NMR, and molecular modeling were used to evaluate the beta-peptide structure in solution, while the monolayer film organization and electron-transfer kinetics were evaluated by cyclic voltammetry, chronoamperometry (CA), and ellipsometry. The peptides were assembled from trifluoroethanol solutions, where they are linear (n = 1) or helical (n = 2) based on CD, NMR, ellipsometry, and modeling evidence. The structure of the SAMs is less well understood. There is evidence for noncompact layers that allow electrolyte ions to approach the interface. Electron-transfer rates for n = 1, 2 were found to be 2500 and 1200 s(-1), respectively, and CA evidence indicated that the transfer is based on the hopping mechanism.
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Affiliation(s)
- Paula A Brooksby
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
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Hartmann BM, Kaar W, Yoo IK, Lua LHL, Falconer RJ, Middelberg APJ. The chromatography-free release, isolation and purification of recombinant peptide for fibril self-assembly. Biotechnol Bioeng 2009; 104:973-85. [PMID: 19530081 DOI: 10.1002/bit.22447] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
One of the major expenses associated with recombinant peptide production is the use of chromatography in the isolation and purification stages of a bioprocess. Here we report a chromatography-free isolation and purification process for recombinant peptide expressed in Escherichia coli (E. coli). Initial peptide release is by homogenization and then by enzymatic cleavage of the peptide-containing fusion protein, directly in the E. coli homogenate. Release is followed by selective solvent precipitation (SSP) to isolate and purify the peptide away from larger cell contaminants. Specifically, we expressed in E. coli the self-assembling beta-sheet forming peptide P(11)-2 in fusion to thioredoxin. Homogenate was heat treated (55 degrees C, 15 min) and then incubated with tobacco etch virus protease (TEVp) to release P(11)-2 having a native N-terminus. SSP with ethanol at room temperature then removed contaminating proteins in an integrated isolation-purification step; it proved necessary to add 250 mM NaCl to homogenate to prevent P(11)-2 from partitioning to the precipitate. This process structure gave recombinant P(11)-2 peptide at 97% polypeptide purity and 40% overall yield, without a single chromatography step. Following buffer-exchange of the 97% pure product by bind-elute chromatography into defined chemical conditions, the resulting peptide was shown to be functionally active and able to form self-assembled fibrils. To the best of our knowledge, this manuscript reports the first published process for chromatography-free recombinant peptide release, isolation and purification. The process proved able to deliver functional recombinant peptide at high purity and potentially low cost, opening cost-sensitive materials applications for peptide-based materials.
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Affiliation(s)
- B M Hartmann
- Centre for Biomolecular Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
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Creczynski-Pasa TB, Millone MAD, Munford ML, de Lima VR, Vieira TO, Benitez GA, Pasa AA, Salvarezza RC, Vela ME. Self-assembled dithiothreitol on Au surfaces for biological applications: phospholipid bilayer formation. Phys Chem Chem Phys 2008; 11:1077-84. [PMID: 19543605 DOI: 10.1039/b811964c] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Self-assembly of dithiothreitol (DTT) on Au(111) from solution deposition has been studied by X-ray photoelectron spectroscopy and electrochemical data. DTT molecules self-assemble on Au(111) in a lying-down configuration irrespective of the concentration and temperature. XPS and electrochemical data indicate a DTT surface coverage of theta approximately 0.16 with two S-head-Au covalent bonds per DTT molecule. The DTT monolayer turns the Au surface hydrophilic enough to allow the formation of fluid dimyristoylphosphatidylcholine (DMPC) bilayer domains by vesicle fusion as revealed by in situ atomic force imaging. Methylene blue (MB) and flavin adenine dinucleotide (FAD) have been used as probes to study molecule transport across the bilayer.
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Affiliation(s)
- Tânia B Creczynski-Pasa
- Departamento de Ciências Farmacêuticas and Departamento de Física, UFSC, C. P. 476, Florianópolis, 88.040-900, Brazil.
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Høiberg-Nielsen R, Tofteng Shelton AP, Sørensen KK, Roessle M, Svergun DI, Thulstrup PW, Jensen KJ, Arleth L. 3- Instead of 4-Helix Formation in a De Novo Designed Protein in Solution Revealed by Small-Angle X-ray Scattering. Chembiochem 2008; 9:2663-72. [DOI: 10.1002/cbic.200800263] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Hartmann B, Kaar W, Falconer R, Middelberg A. Chromatography-free peptide biomanufacture. J Biotechnol 2008. [DOI: 10.1016/j.jbiotec.2008.07.1079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Nishimori Y, Kanaizuka K, Murata M, Nishihara H. Synthesis of molecular wires of linear and branched bis(terpyridine)-complex oligomers and electrochemical observation of through-bond redox conduction. Chem Asian J 2007; 2:367-76. [PMID: 17441172 DOI: 10.1002/asia.200600350] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Films of linear and branched oligomer wires of Fe(tpy)2 (tpy = 2,2':6',2''-terpyridine) were constructed on a gold-electrode surface by the interfacial stepwise coordination method, in which a surface-anchoring ligand, (tpy-C6H4N=NC6H4-S)2 (1), two bridging ligands, 1,4-(tpy)2C6H4 (3) and 1,3,5-(C[triple bond]C-tpy)3C6H3 (4), and metal ions were used. The quantitative complexation of the ligands and Fe(II) ions was monitored by electrochemical measurements in up to eight complexation cycles for linear oligomers of 3 and in up to four cycles for branched oligomers of 4. STM observation of branched oligomers at low surface coverage showed an even distribution of nanodots of uniform size and shape, which suggests the quantitative formation of dendritic structures. The electron-transport mechanism and kinetics for the redox reaction of the films of linear and branched oligomer wires were analyzed by potential-step chronoamperometry (PSCA). The unique current-versus-time behavior observed under all conditions indicates that electron conduction occurs not by diffusional motion but by successive electron hopping between neighboring redox sites within a molecular wire. Redox conduction in a single molecular wire in a redox-polymer film has not been reported previously. The analysis provided the rate constant for electron transfer between the electrode and the nearest redox-complex moiety, k1 (s(-1)), as well as that for intrawire electron transfer between neighboring redox-complex moieties, k2 (cm2 mol(-1) s(-1)). The strong effect of the electrolyte concentration on both k1 and k2 indicates that the counterion motion limits the electron-hopping rate at lower electrolyte concentrations. Analysis of the dependence of k1 and k2 on the potential gave intrinsic kinetic parameters without overpotential effects: (k1(0) = 110 s(-1), k2(0) = 2.6x10(12) cm2 mol(-1) s(-1) for [n Fe3], and k1(0) = 100 s(-1), k2(0) = 4.1x10(11) cm2 mol(-1) s(-1) for [n Fe4] (n = number of complexation cycles).
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Affiliation(s)
- Yoshihiko Nishimori
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Pernille Tofteng A, Hansen TH, Brask J, Nielsen J, Thulstrup PW, Jensen KJ. Synthesis of functionalized de novo designed 8–16 kDa model proteins towards metal ion-binding and esterase activity. Org Biomol Chem 2007; 5:2225-33. [PMID: 17609753 DOI: 10.1039/b704159d] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
De novo design and total chemical synthesis of proteins provides a powerful approach for biological and biophysical studies with the ability to prepare artificial proteins with tailored properties, potentially of importance for biophysical studies, material science, nanobioscience, and as molecular probes. In this paper, the previously developed concept of carbohydrates as templates is employed in the de novo design of model proteins (artificial helix bundles) termed 'carboproteins'. The 4-alpha-helix bundle is a macromolecular structure, where four amphiphilic alpha-helical peptide strands form a hydrophobic core. Here this structure is modified towards achieving metal ion-binding and catalytic activity. We report: (i) test of directional effects from different tetravalent carbohydrate templates, (ii) synthesis and evaluation of carboproteins functionalized with phenol, pyridyl or imidazolyl moieties as potential ligands for metal ion-binding as well as for catalysis. Our results include: (i) support of our previous 'controversial' finding that for some carboproteins the degree of alpha-helicity depends on the template, i.e., that there is, to some extent, a controlling effect from the template, (ii) demonstration of binding of Cu(ii) to tetra-functional carboproteins by electrospray ionization-time of flight-mass spectrometry (ESI-TOF-MS), UV-VIS absorption spectroscopy and size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS); (iii) a kinetic investigation of the esterase activity.
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Affiliation(s)
- A Pernille Tofteng
- Department of Natural Sciences, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
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