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Koltover VK. Magnetic isotope effects and nuclear spin catalysis in living cells and biomolecular motors: recent advances and future outlooks: Nuclear spin catalysis. Biophys Rev 2023; 15:999-1006. [PMID: 37974974 PMCID: PMC10643427 DOI: 10.1007/s12551-023-01162-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 09/25/2023] [Indexed: 11/19/2023] Open
Abstract
Biomolecular nanoreactors are constructed from chemical elements many of which have magnetic and nonmagnetic stable isotopes. The magnetic isotope effects (MIE) were discovered in experiments with the cells enriched with different isotopes of magnesium, magnetic or nonmagnetic ones. The striking catalytic effect of the magnetic isotope, 25Mg, was revealed in the reaction of ATP hydrolysis driven by myosin, the biomolecular motor utilizing the chemical energy of ATP to perform the mechanical work. The rate of the enzymatic ATP hydrolysis with 25Mg as the enzyme cofactor is twice higher than the rates of the reactions with nonmagnetic 24Mg or 26Mg. A similar effect of the nuclear spin catalysis was revealed in the experiments with zinc as the myosin cofactor. MIE unambiguously indicate that, in the chemo-mechanical process catalyzed by the molecular motor, there is a limiting step which depends on the electron spin state of the reagents, and this step is accelerated by the nuclear spin of the magnetic isotope. The recent developments in this field highlight promising venues for future research of MIE in biophysics with possible applications of the magnetic isotopes in medical physics including radiation medicine and biomedical effects of electromagnetic fields.
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Affiliation(s)
- Vitaly K. Koltover
- Federal Research Center of Problems of Chemical Physics and Medical Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow, Region 142432 Russian Federation
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2
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Coulter SM, Pentlavalli S, Vora LK, An Y, Cross ER, Peng K, McAulay K, Schweins R, Donnelly RF, McCarthy HO, Laverty G. Enzyme-Triggered l-α/d-Peptide Hydrogels as a Long-Acting Injectable Platform for Systemic Delivery of HIV/AIDS Drugs. Adv Healthc Mater 2023; 12:e2203198. [PMID: 36880399 DOI: 10.1002/adhm.202203198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/24/2023] [Indexed: 03/08/2023]
Abstract
Eradicating HIV/AIDS by 2030 is a central goal of the World Health Organization. Patient adherence to complicated dosage regimens remains a key barrier. There is a need for convenient long-acting formulations that deliver drugs over sustained periods. This paper presents an alternative platform, an injectable in situ forming hydrogel implant to deliver a model antiretroviral drug (zidovudine [AZT]) over 28 days. The formulation is a self-assembling ultrashort d or l-α peptide hydrogelator, namely phosphorylated (naphthalene-2-ly)-acetyl-diphenylalanine-lysine-tyrosine-OH (NapFFKY[p]-OH), covalently conjugated to zidovudine via an ester linkage. Rheological analysis demonstrates phosphatase enzyme instructed self-assembly, with hydrogels forming within minutes. Small angle neutron scattering data suggest hydrogels form narrow radius (≈2 nm), large length fibers closely fitting the flexible cylinder elliptical model. d-Peptides are particularly promising for long-acting delivery, displaying protease resistance for 28 days. Drug release, via hydrolysis of the ester linkage, progress under physiological conditions (37 °C, pH 7.4, H2 O). Subcutaneous administration of Napffk(AZT)Y[p]G-OH in Sprague Dawley rats demonstrate zidovudine blood plasma concentrations within the half maximal inhibitory concentration (IC50 ) range (30-130 ng mL-1 ) for 35 days. This work is a proof-of-concept for the development of a long-acting combined injectable in situ forming peptide hydrogel implant. These products are imperative given their potential impact on society.
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Affiliation(s)
- Sophie M Coulter
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, Co. Antrim, Northern Ireland, BT9 7BL, UK
| | - Sreekanth Pentlavalli
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, Co. Antrim, Northern Ireland, BT9 7BL, UK
| | - Lalitkumar K Vora
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, Co. Antrim, Northern Ireland, BT9 7BL, UK
| | - Yuming An
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, Co. Antrim, Northern Ireland, BT9 7BL, UK
| | - Emily R Cross
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, Co. Antrim, Northern Ireland, BT9 7BL, UK
| | - Ke Peng
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, Co. Antrim, Northern Ireland, BT9 7BL, UK
| | - Kate McAulay
- School of Chemistry, University of Glasgow, Joseph Black Building, Glasgow, Scotland, G12 8QQ, UK
- School of Computing, Engineering and Built Environment, Glasgow Caledonian University, Glasgow, Scotland, G4 0BA, UK
| | - Ralf Schweins
- Large Scale Structures Group, Institut Laue - Langevin, 71 Avenue des Martyrs, CS 20156, Grenoble Cedex 9, 38042, France
| | - Ryan F Donnelly
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, Co. Antrim, Northern Ireland, BT9 7BL, UK
| | - Helen O McCarthy
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, Co. Antrim, Northern Ireland, BT9 7BL, UK
| | - Garry Laverty
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, Co. Antrim, Northern Ireland, BT9 7BL, UK
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Koralewski M, Baranowski M, Ryzner A. Probing physical invariance between enantiomers: The magnetooptical and refractive properties of the simplest chiral amino acid – Alanine. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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5
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Synchronization in Non-Mirror-Symmetrical Chirogenesis: Non-Helical π–Conjugated Polymers with Helical Polysilane Copolymers in Co-Colloids. Symmetry (Basel) 2021. [DOI: 10.3390/sym13040594] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A curious question is whether two types of chiroptical amplifications, called sergeants-and-soldiers (Ser-Sol) and majority-rule (Maj) effects, between non-charged helical copolymers and non-charged, non-helical homopolymers occur when copolymer encounter homopolymer in co-colloids. To address these topics, the present study chose (i) two helical polysilane copolymers (HCPSs) carrying (S)- or (R)-2-methylbutyl with isobutyl groups as chiral/achiral co-pendants (type I) and (S)- and (R)-2-methylbutyl groups as chiral/chiral co-pendants (type II) and (ii) two blue luminescent π-conjugated polymers, poly[(dioctylfluorene)-alt-(trans-vinylene)] (PFV8) and poly(dioctylfluorene) (PF8). Analyses of circular dichroism (CD) and circularly polarized luminescence (CPL) spectral datasets of the co-colloids indicated noticeable, chiroptical inversion in the Ser-Sol effect of PFV8/PF8 with type I HCPS. PF8 with type IIHCPS showed the anomalous Maj rule with chiroptical inversion though PFV8 with type IIHCPS was the normal Maj effect. The noticeable non-mirror-symmetric CD-and-CPL characteristics and marked differences in hydrodynamic sizes of these colloids were assumed to originate from non-mirror-symmetrical main-chain stiffness of HCPSs in dilute toluene solution. The present chirality/helicity transfer experiments alongside of previous/recent publications reported by other workers and us allowed to raise the fundamental question; is mirror symmetry on macroscopic levels in the ground and photoexcited states rigorously conserved?
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6
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Handed Mirror Symmetry Breaking at the Photo-Excited State of π-Conjugated Rotamers in Solutions. Symmetry (Basel) 2021. [DOI: 10.3390/sym13020272] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The quest to decode the evolution of homochirality of life on earth has stimulated research at the molecular level. In this study, handed mirror symmetry breaking, and molecular parity violation hypotheses of systematically designed π-conjugated rotamers possessing anthracene and bianthracene core were evinced via circularly polarized luminescence (CPL) and circular dichroism (CD). The CPL signals were found to exhibit a (−)-sign, and a handed dissymmetry ratio, which increased with viscosity of achiral solvents depending on the rotation barrier of rotamers. The time-resolved photoluminescence spectroscopy and quantum efficiency measurement of these luminophores in selected solvents reinforced the hypothesis of a viscosity-induced consistent increase of the (−)-sign handed CPL signals.
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7
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Madhanagopal B, More SH, Bansode ND, Ganesh KN. Conformation and Morphology of 4-(NH 2/OH)-Substituted l/d-Prolyl Polypeptides: Effect of Homo- and Heterochiral Backbones on Formation of β-Structures and Nanofibers. ACS OMEGA 2020; 5:21781-21795. [PMID: 32905392 PMCID: PMC7469381 DOI: 10.1021/acsomega.0c02826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 08/04/2020] [Indexed: 06/11/2023]
Abstract
The relative stereochemistry of C2 and C4 in 4-substituted prolyl polypeptides plays an important role in defining the derived conformation in solution. cis-(2S,4S)-Amino/hydroxy-l-prolyl polypeptide (lC-Amp 9/lC-Hyp 9) shows a PPII conformation in phosphate buffer and a β-structure in a relatively hydrophobic solvent, trifluoroethanol (TFE). It is now demonstrated that the homochiral enantiomeric cis-substituted d-prolyl polypeptide (dC-Amp 9/dC-Hyp 9) exhibits mirror image β-structures in TFE. In the case of alternating heterochiral prolyl peptides, it is the trans-substituted [lT(2S,4R)-dT(2R,4S)] n prolyl polypeptide that shows β-structures in TFE, while the cis-substituted [lC(2S,4S)-dC(2R,4R)] n prolyl polypeptide is disordered in both phosphate buffer and TFE. The results highlight the important chirality-specific structural requirements for β-structure formation. The observed conformation in solution (circular dichroism (CD)) is also correlated with the morphology of the self-assemblies (field emission scanning electron microscopy (FESEM)), with the PPII form leading to spherical nanoparticles and β-structures leading to nanofiber formation. The results shed light on the role of relative stereochemistry at C2 and C4 in defining the polyproline peptide conformation in solution and how different conformations drive self-assemblies of peptides toward specific nanostructures.
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Affiliation(s)
- Bharath
Raj Madhanagopal
- Indian
Institute of Science Education and Research (IISER), Tirupati, Karkambadi Road, Tirupati 517507, Andhra Pradesh, India
| | - Shahaji H. More
- Indian
Institute of Science Education and Research (IISER), Tirupati, Karkambadi Road, Tirupati 517507, Andhra Pradesh, India
| | - Nitin D. Bansode
- LCPO,
ENSCBP, UMR 5629, University of Bordeaux, Pessac 33600, France
| | - Krishna N. Ganesh
- Indian
Institute of Science Education and Research (IISER), Tirupati, Karkambadi Road, Tirupati 517507, Andhra Pradesh, India
- Indian
Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
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8
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Koltover VK, Labyntseva RD, Karandashev VK. Magnetic-Isotope Effects of Magnesium and Zinc in Enzymatic ATP Hydrolysis Driven by Molecular Motors. Biophysics (Nagoya-shi) 2020. [DOI: 10.1134/s0006350920030094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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9
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Questions of Mirror Symmetry at the Photoexcited and Ground States of Non-Rigid Luminophores Raised by Circularly Polarized Luminescence and Circular Dichroism Spectroscopy. Part 2: Perylenes, BODIPYs, Molecular Scintillators, Coumarins, Rhodamine B, and DCM. Symmetry (Basel) 2019. [DOI: 10.3390/sym11030363] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We investigated whether semi-rigid and non-rigid π-conjugated fluorophores in the photoexcited (S1) and ground (S0) states exhibited mirror symmetry by circularly polarized luminescence (CPL) and circular dichroism (CD) spectroscopy using a range of compounds dissolved in achiral liquids. The fluorophores tested were six perylenes, six scintillators, 11 coumarins, two pyrromethene difluoroborates (BODIPYs), rhodamine B (RhB), and 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM). All the fluorophores showed negative-sign CPL signals in the ultraviolet (UV)–visible region, suggesting energetically non-equivalent and non-mirror image structures in the S1 state. The dissymmetry ratio of the CPL (glum) increased discontinuously from approximately −0.2 × 10−3 to −2.0 × 10−3, as the viscosity of the liquids increased. Among these liquids, C2-symmetrical stilbene 420 showed glum ≈ −0.5 × 10−3 at 408 nm in H2O and D2O, while, in a viscous alkanediol, the signal was amplified to glum ≈ −2.0 × 10−3. Moreover, BODIPYs, RhB, and DCM in the S0 states revealed weak (−)-sign CD signals with dissymmetry ratios (gabs) ≈ −1.4 × 10−5 at λmax/λext. The origin of the (−)-sign CPL and the (−)-sign CD signals may arise from an electroweak charge at the polyatomic level. Our CPL and CD spectral analysis could be a possible answer to the molecular parity violation hypothesis based on a weak neutral current of Z0 boson origin that could connect to the origin of biomolecular handedness.
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10
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Dupuy FG, Pagano I, Andenoro K, Peralta MF, Elhady Y, Heinrich F, Tristram-Nagle S. Selective Interaction of Colistin with Lipid Model Membranes. Biophys J 2019; 114:919-928. [PMID: 29490251 DOI: 10.1016/j.bpj.2017.12.027] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/19/2017] [Accepted: 12/21/2017] [Indexed: 11/24/2022] Open
Abstract
Although colistin's clinical use is limited due to its nephrotoxicity, colistin is considered to be an antibiotic of last resort because it is used to treat patients infected with multidrug-resistant bacteria. In an effort to provide molecular details about colistin's ability to kill Gram-negative (G(-)) but not Gram-positive (G(+)) bacteria, we investigated the biophysics of the interaction between colistin and lipid mixtures mimicking the cytoplasmic membrane of G(+), G(-) bacteria as well as eukaryotic cells. Two different models of the G(-) outer membrane (OM) were assayed: lipid A with two deoxy-manno-octulosonyl sugar residues, and Escherichia coli lipopolysaccharide mixed with dilaurylphosphatidylglycerol. We used circular dichroism and x-ray diffuse scattering at low and wide angle in stacked multilayered samples, and neutron reflectivity of single, tethered bilayers mixed with colistin. We found no differences in secondary structure when colistin was bound to G(-) versus G(+) membrane mimics, ruling out a protein conformational change as the cause of this difference. However, bending modulus KC perturbation was quite irregular for the G(-) inner membrane, where colistin produced a softening of the membranes at an intermediate lipid/peptide molar ratio but stiffening at lower and higher peptide concentrations, whereas in G(+) and eukaryotic mimics there was only a slight softening. Acyl chain order in G(-) was perturbed similarly to KC. In G(+), there was only a slight softening and disordering effect, whereas in OM mimics, there was a slight stiffening and ordering of both membranes with increasing colistin. X-ray and neutron reflectivity structural results reveal colistin partitions deepest to reach the hydrocarbon interior in G(-) membranes, but remains in the headgroup region in G(+), OM, and eukaryotic mimics. It is possible that domain formation is responsible for the erratic response of G(-) inner membranes to colistin and for its deeper penetration, which could increase membrane permeability.
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Affiliation(s)
- Fernando G Dupuy
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania; Instituto Superior de Investigaciones Biológicas (INSIBIO) CONICET-UNT and Instituto de Química Biológica "Dr Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT, San Miguel de Tucumán, Argentina
| | - Isabella Pagano
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Kathryn Andenoro
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Maria F Peralta
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania; Instituto de Investigación Médica M y M Ferreyra, CONICET-National University of Córdoba, Córdoba, Argentina
| | - Yasmene Elhady
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Frank Heinrich
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania; National Institute of Standards and Technology Center for Neutron Research, Gaithersburg, Maryland
| | - Stephanie Tristram-Nagle
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania.
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11
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Fujiki M, Koe JR, Mori T, Kimura Y. Questions of Mirror Symmetry at the Photoexcited and Ground States of Non-Rigid Luminophores Raised by Circularly Polarized Luminescence and Circular Dichroism Spectroscopy: Part 1. Oligofluorenes, Oligophenylenes, Binaphthyls and Fused Aromatics. Molecules 2018; 23:E2606. [PMID: 30314330 PMCID: PMC6222818 DOI: 10.3390/molecules23102606] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/01/2018] [Accepted: 10/06/2018] [Indexed: 11/17/2022] Open
Abstract
We report experimental tests of whether non-rigid, π-conjugated luminophores in the photoexcited (S₁) and ground (S₀) states dissolved in achiral liquids are mirror symmetrical by means of circularly polarized luminescence (CPL) and circular dichroism (CD) spectroscopy. Herein, we chose ten oligofluorenes, eleven linear/cyclic oligo-p-arylenes, three binaphthyls and five fused aromatics, substituted with alkyl, alkoxy, phenyl and phenylethynyl groups and also with no substituents. Without exception, all these non-rigid luminophores showed negative-sign CPL signals in the UV-visible region, suggesting temporal generation of energetically non-equivalent non-mirror image structures as far-from equilibrium open-flow systems at the S₁ state. For comparison, unsubstituted naphthalene, anthracene, tetracene and pyrene, which are achiral, rigid, planar luminophores, did not obviously show CPL/CD signals. However, camphor, which is a rigid chiral luminophore, showed mirror-image CPL/CD signals. The dissymmetry ratio of CPL (glum) for the oligofluorenes increased discontinuously, ranging from ≈ -(0.2 to 2.0) × 10-3, when the viscosity of the liquids increased. When the fluorene ring number increased, the glum value extrapolated at [η] = 0 reached -0.8 × 10-3 at 420 nm, leading to (⁻)-CPL signals predicted in the vacuum state. Our comprehensive CPL and CD study should provide a possible answer to the molecular parity violation hypothesis arising due to the weak neutral current mediated by the Z⁰-boson.
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Affiliation(s)
- Michiya Fujiki
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0036, Japan.
| | - Julian R Koe
- Department of Natural Sciences, International Christian University (ICU), 3-10-2 Mitaka, Tokyo, 181-8585, Japan.
| | - Takashi Mori
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0036, Japan.
| | - Yoshihiro Kimura
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0036, Japan.
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12
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Elia V, Oliva R, Napoli E, Germano R, Pinto G, Lista L, Niccoli M, Toso D, Vitiello G, Trifuoggi M, Giarra A, Yinnon TA. Experimental study of physicochemical changes in water by iterative contact with hydrophilic polymers: A comparison between Cellulose and Nafion. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.07.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Childers MC, Towse CL, Daggett V. Molecular dynamics-derived rotamer libraries for d-amino acids within homochiral and heterochiral polypeptides. Protein Eng Des Sel 2018; 31:191-204. [PMID: 29992252 PMCID: PMC6205366 DOI: 10.1093/protein/gzy016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 06/15/2018] [Indexed: 01/06/2023] Open
Abstract
Computational resources have contributed to the design and engineering of novel proteins by integrating genomic, structural and dynamic aspects of proteins. Non-canonical amino acids, such as d-amino acids, expand the available sequence space for designing and engineering proteins; however, the rotamer libraries for d-amino acids are usually constructed as the mirror images of l-amino acid rotamer libraries, an assumption that has not been tested. To this end, we have performed molecular dynamics (MD) simulations of model host-guest peptide systems containing d-amino acids. Our simulations systematically address the applicability of the mirror image convention as well as the effects of neighboring residue chirality. Rotamer libraries derived from these systems provide realistic rotamer distributions suitable for use in both rational and computational design workflows. Our simulations also address the impact of chirality on the intrinsic conformational preferences of amino acids, providing fundamental insights into the relationship between chirality and biomolecular dynamics. While d-amino acids are rare in naturally occurring proteins, they are used in designed proteins to stabilize a desired conformation, increase bioavailability or confer favorable biochemical and physical attributes. Here, we present d-amino acid rotamer libraries derived from MD simulations of alanine-based host-guest pentapeptides and show how certain residues can deviate from mirror image symmetry. Our simulations directly model d-amino acids as guest residues within the chiral l-Ala and d-Ala pentapeptide series to explicitly incorporate any contributions resulting from the chiralities of neighboring residues.
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Affiliation(s)
| | - Clare-Louise Towse
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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14
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Affiliation(s)
- Liora Werber
- Department of Chemistry and the Institute of Nanotechnology; Bar-Ilan University; Ramat Gan Israel
| | - Yitzhak Mastai
- Department of Chemistry and the Institute of Nanotechnology; Bar-Ilan University; Ramat Gan Israel
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15
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Koltover VK. Nuclear spin catalysis: From physics of liquid matter to medical physics. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2016.11.083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Koltover VK, Labyntseva RD, Karandashev VK, Kosterin SO. Magnetic isotope of magnesium accelerates ATP hydrolysis catalyzed by myosin. Biophysics (Nagoya-shi) 2016. [DOI: 10.1134/s0006350916020068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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17
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Fujiki M, Donguri Y, Zhao Y, Nakao A, Suzuki N, Yoshida K, Zhang W. Photon magic: chiroptical polarisation, depolarisation, inversion, retention and switching of non-photochromic light-emitting polymers in optofluidic medium. Polym Chem 2015. [DOI: 10.1039/c4py01337a] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A circularly polarised photon hand, l- and r-, was not a deterministic factor for the induced chiroptical sign of π-conjugated polymer aggregates. This anomaly originates from circular dichroism inversion characteristics between shorter and longer π–π* bands.
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Affiliation(s)
- Michiya Fujiki
- Graduate School of Materials Science
- Nara Institute of Science and Technology
- Ikoma
- Japan
| | - Yuri Donguri
- Graduate School of Materials Science
- Nara Institute of Science and Technology
- Ikoma
- Japan
| | - Yin Zhao
- Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
| | - Ayako Nakao
- Graduate School of Materials Science
- Nara Institute of Science and Technology
- Ikoma
- Japan
| | - Nozomu Suzuki
- Graduate School of Materials Science
- Nara Institute of Science and Technology
- Ikoma
- Japan
| | - Kana Yoshida
- Graduate School of Materials Science
- Nara Institute of Science and Technology
- Ikoma
- Japan
| | - Wei Zhang
- Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
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18
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Supramolecular Chirality: Solvent Chirality Transfer in Molecular Chemistry and Polymer Chemistry. Symmetry (Basel) 2014. [DOI: 10.3390/sym6030677] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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19
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Park MJ, General T, Lee SP. Physicochemical Properties of Roasted Soybean Flour Bioconverted by Solid-State Fermentation Using Bacillus subtilis and Lactobacillus plantarum. Prev Nutr Food Sci 2014; 17:36-45. [PMID: 24471061 PMCID: PMC3866766 DOI: 10.3746/pnf.2012.17.1.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 02/09/2012] [Indexed: 11/06/2022] Open
Abstract
To produce novel cheese-like fermented soybean, the solid-state fermentation of roasted soybean flour (RSF) was performed using 1.0% inoculum Bacillus subtilis HA and Lactobacillus plantarum, with the initial 60% substrate moisture for 10 hr at 42°C, resulting in pH 6.5, 0.82% acidity, 3.5% mucilage, 14.3 unit/g protease activity, 7.6 unit/g fibrinolytic activity, 216 mg% tyrosine content and 1.7×1010 CFU/g of viable cell counts. After the second lactic acid fermentation with 10∼30% skim milk powder, the fermented RSF resulted in an increase in acidity with 1.64∼1.99%, tyrosine content with 246∼308 mg% and protease activity in the range of 5.2∼17.5 unit/g and 0.966 water activity. Viable cell counts as probiotics indicated 1.6×108 CFU/g of B. subtilis and 7.3×1010 CFU/g of L. plantarum. The firmness of the first fermented RSF with 2,491 g·ømm−1 greatly decreased to 1,533 g·ømm−1 in the second fermented RSF, although firmness was slightly increased by adding a higher content of skim milk. The consistency of the second fermented RSF also decreased greatly from 55,640 to 3,264∼3,998 in the presence of 10∼30% skim milk. The effective hydrolysis of soy protein and skim milk protein in the fermented RSF was confirmed. Thus, the second fermented RSF with a sour taste and flavor showed similar textural properties to commercial soft cheese.
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Affiliation(s)
- Min-Ju Park
- Department of Food Science and Technology, Keimyung University, Daegu 704-701, Korea
| | - Thiyam General
- Department of Bio-chemical Engineering, Dongseo University, Busan 617-716, Korea
| | - Sam-Pin Lee
- Department of Food Science and Technology, Keimyung University, Daegu 704-701, Korea
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20
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Fujiki M, Kawagoe Y, Nakano Y, Nakao A. Mirror-symmetry-breaking in poly[(9,9-di-n-octylfluorenyl- 2,7-diyl)-alt-biphenyl] (PF8P2) is susceptible to terpene chirality, achiral solvents, and mechanical stirring. Molecules 2013; 18:7035-57. [PMID: 23774943 PMCID: PMC6269764 DOI: 10.3390/molecules18067035] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/03/2013] [Accepted: 06/03/2013] [Indexed: 12/04/2022] Open
Abstract
Solvent chirality transfer of (S)-/(R)-limonenes allows the instant generation of optically active PF8P2 aggregates with distinct circular dichroism (CD)/circularly polarized luminescence (CPL) amplitudes with a high quantum yield of 16-20%. The present paper also reports subtle mirror-symmetry-breaking effects in CD-/CPL-amplitude and sign, CD/UV-vis spectral wavelengths, and photodynamics of the aggregates, though the reasons for the anomaly are unsolved. However, these photophysical properties depend on (i) the chemical natures of chiral and achiral molecules when used in solvent quantity, (ii) clockwise and counterclockwise stirring operations, and (iii) the order of addition of limonene and methanol to the chloroform solution.
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Affiliation(s)
- Michiya Fujiki
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan; E-Mails: (Y.K.); (A.N.)
| | - Yoshifumi Kawagoe
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan; E-Mails: (Y.K.); (A.N.)
| | - Yoko Nakano
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan; E-Mails: (Y.K.); (A.N.)
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720-1760, USA; E-Mail:
| | - Ayako Nakao
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan; E-Mails: (Y.K.); (A.N.)
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21
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Shinitzky M. Space asymmetry as a possible global feature. Chirality 2013; 25:308-11. [PMID: 23580358 DOI: 10.1002/chir.22152] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 11/22/2012] [Accepted: 12/10/2012] [Indexed: 11/11/2022]
Abstract
A series of reports in the literature indicated symmetry breaking in assemblies of chiral molecules of opposite handedness. These unexpected observations could be accounted for as being generated by the "parity violation" of the nuclear weak force, combined with an autocatalytic amplification process. However, in many such cases, in particular of chiral fluids, this putative mechanism is far from providing a reasonable explanation for such discrimination. In this article it is suggested that space may have deviated a priori from absolute symmetry, a possibility which complies with observations in atoms and molecules and may even be implicated in the asymmetrical configuration of spiral galaxies. Space asymmetry can be extrapolated to a difference between the relative statistical weights of the "right" versus the "left" directions with respect to Euclidian coordinates or, analogously, to a difference between the clockwise and anticlockwise orientations in polar coordinates. The difference in weights of these directions in space is estimated to be around 1%, based on the differences observed in density values of chiral fluids and chiral crystals of NaClO3. The implied asymmetry of time, as the conjugated fourth dimension, suggests a similar difference in magnitude of the time coordinate in a right-handed versus left-handed space, which is feasible for experimental verification.
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Affiliation(s)
- Meir Shinitzky
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel.
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22
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Cogan U, Shpigelman A, Portnaya I, Rutenberg A, Scolnik Y, Shinitzky M. Intermolecular chiral assemblies in R(-) and S(+) 2-butanol detected by microcalorimetry measurements. Chirality 2012; 24:500-5. [PMID: 22570171 DOI: 10.1002/chir.22033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2011] [Accepted: 02/03/2012] [Indexed: 11/06/2022]
Abstract
Supramolecular chiral assemblies of R(-) and S(+) 2-butanol, in their neat form or when dissolved in their nonchiral isomer isobutanol, were evaluated by isothermal titration calorimetry (ITC) ensuing mixing. Dilution of 0.5 M solution of R(-) 2-butanol in isobutanol into the latter liberated heat of several calories per mole, which was approximately double than that obtained in parallel dilutions of S(+) 2-butanol in isobutanol. The ITC dilution profiles indicated an estimate of about 100 isobutanol solvent molecules surrounding each of the 2-butanol enantiomers, presumably arranged in chiral configurations, with different adopted order between the isomers. Mixings of neat R and S 2-butanol were followed by endothermic ITC profiles, indicating that, in racemic 2-butanol, both the supramolecular order and the intermolecular binding energies are lower than in each of the neat chiral isomers. The diversion from symmetrical ITC patterns in these mixings indicated again a subtle difference in molecular organization between the neat enantiomers. It should be noted that the presence of impurities, α-pinene and teterhydrofuran, at a level totaling 0.5%, did not influence the ITC heat flow profiles. The findings of this study demonstrate for the first time that chiral solutes in organic solvents are expected to acquire asymmetric solvent envelopes that may be different between the enantiomers, thus broadening this phenomenon beyond the previously demonstrated cases in aqueous solutions.
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Affiliation(s)
- Uri Cogan
- Department of Biotechnology and Food Engineering, Technion, Haifa, 32000, Israel
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23
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Liang H, Hu X, Fang G, Shao S, Guo A, Guo Z. Pairwise interaction enthalpies of enantiomers of β-amino alcohols in DMSO + H2O mixtures at 298.15 K. Chirality 2012; 24:374-85. [DOI: 10.1002/chir.22021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Accepted: 11/02/2011] [Indexed: 11/10/2022]
Affiliation(s)
- Hongyu Liang
- College of Chemistry and Materials Engineering; Wenzhou University; Wenzhou; 325035; China
| | - Xingen Hu
- College of Chemistry and Materials Engineering; Wenzhou University; Wenzhou; 325035; China
| | - Guoyong Fang
- College of Chemistry and Materials Engineering; Wenzhou University; Wenzhou; 325035; China
| | - Shuang Shao
- Department of Chemistry; Zhejiang International Studies University; Hangzhou; 310012; China
| | - Aidi Guo
- College of Chemistry and Materials Engineering; Wenzhou University; Wenzhou; 325035; China
| | - Zheng Guo
- College of Chemistry and Materials Engineering; Wenzhou University; Wenzhou; 325035; China
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24
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Lo Nostro P, Ninham BW. Hofmeister phenomena: an update on ion specificity in biology. Chem Rev 2012; 112:2286-322. [PMID: 22251403 DOI: 10.1021/cr200271j] [Citation(s) in RCA: 671] [Impact Index Per Article: 55.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Pierandrea Lo Nostro
- Department of Chemistry and CSGI, University of Florence, 50019 Sesto Fiorentino (Firenze), Italy.
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25
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Antunes JC, Pereira CL, Molinos M, Ferreira-da-Silva F, Dessı̀ M, Gloria A, Ambrosio L, Gonçalves RM, Barbosa MA. Layer-by-Layer Self-Assembly of Chitosan and Poly(γ-glutamic acid) into Polyelectrolyte Complexes. Biomacromolecules 2011; 12:4183-95. [DOI: 10.1021/bm2008235] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | | | | | | | - Mariagemiliana Dessı̀
- Institute of Composite and Biomedical Materials, National Research Council,
P.le Tecchio 80, 80125 Naples, Italy
| | - Antonio Gloria
- Institute of Composite and Biomedical Materials, National Research Council,
P.le Tecchio 80, 80125 Naples, Italy
| | - Luigi Ambrosio
- Institute of Composite and Biomedical Materials, National Research Council,
P.le Tecchio 80, 80125 Naples, Italy
| | | | - Mário A. Barbosa
- Institute of Composite and Biomedical Materials, National Research Council,
P.le Tecchio 80, 80125 Naples, Italy
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26
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Bargueño P, Miret-Artés S, Gonzalo I. Quantum stochastic resonance in parity violating chiral molecules. Phys Chem Chem Phys 2011; 13:850-3. [PMID: 21063621 DOI: 10.1039/c0cp01319f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In order to explore parity violating effects in chiral molecules, of interest in some models of evolution towards homochirality, quantum stochastic resonance (QSR) is studied for the population difference between the two enantiomers of a chiral molecule (hence for the optical activity of the sample), under low viscous friction and in the deep quantum regime. The molecule is described by a two-state model in an asymmetric double well potential where the asymmetry is given by the known predicted parity violating energy difference (PVED) between enantiomers. In the linear response to an external driving field that lowers and rises alternatively each one of the minima of the well, a signal of QSR is predicted only in the case that the PVED is different from zero, the resonance condition being independent on tunneling between the two enantiomers. It is shown that, at resonance, the fluctuations of the first order contribution to the internal energy are zero. Due to the small value of the PVED, the resonance would occur in the ultracold regime. Some proposals concerning the external driving field are suggested.
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Affiliation(s)
- Pedro Bargueño
- Instituto de Física Fundamental (CSIC), Serrano 123, 28006 Madrid, Spain.
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27
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Information Storage in Liquids with Ordered Molecular Assemblies. ENTROPY 2010. [DOI: 10.3390/e13010001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Mirror Symmetry Breaking in Helical Polysilanes: Preference between Left and Right of Chemical and Physical Origin. Symmetry (Basel) 2010. [DOI: 10.3390/sym2031625] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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29
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Enantiodifferent proton exchange in alanine and asparagine in the presence of H(2)(17)O. J Mol Evol 2010; 71:23-33. [PMID: 20593168 DOI: 10.1007/s00239-010-9361-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2009] [Accepted: 05/26/2010] [Indexed: 10/19/2022]
Abstract
Using Time Domain (1)H Nuclear Magnetic Resonance with H (2) (17) O (H (2) (17) O-TD-(1)HNMR), we found [H (2) (17) O]- and pH-controlled chiral differences in proton exchange properties in alanine (Ala) and asparagine (Asn). To minimize and equalize chemical impurities, Asn enantiomers were purified by crystallization from racemic solution. At <0.1 M H (2) (17) O, a shift in isoelectric pH (pI) occurred, approximately 1.14 kJ mol(-1) L: -D: -Asn DeltaDeltaG (o)' in the 5.91-6.42 pH range. One potential source for this asymmetry is the enantio-different magnetic moments (L: mu upward arrow not equal D: mu downward arrow) produced by neutral ring currents in the chiral center, leading to enantio-different nuclear spin organization and charge distribution in the amino group. At >or=pI, dissimilar interactions may occur in the hydration of the amino group with H (2) (17) O (NH(2)/H (2) (17) O not equal NH(2)/H (2) (16) O; NH(3) (+)/H (2) (17) O not equal NH(2)/H (2) (17) O; L: -*C-NH(2)/H (2) (17) O not equal D: -*C-NH(2)/H (2) (17) O). As L: mu upward arrow not equal D: mu downward arrow, the L: -*C-amino and the D: -*C-amino groups are diastereo spin-isomers. The nuclear spin of (17)O may be parallel or antiparallel with the ortho-(1)H(1)H pair; hence two ortho-H (2) (17) O molecules exist, also diastereo spin-isomers. As the pK of H (2) (17) O is different from H (2) (16) O, dissimilarities between L: -*C- and D: -*C-amino groups are converted into proton exchange differences. During H (2) (17) O-TD-(1)HNMR, the H (2) (17) O molecule is a "probe" of the state of the amino group. Regarding prebiotic evolution: prebiotic chirality may not require stochastic symmetry breaking or preexisting chiral conditions; chemical chiral effects due to L: mu upward arrow not equal D: mu downward arrow are small and need chiral amplification to generate an enantiomeric excess significant for prebiotic evolution; and prebiotic symmetry breaking was homochiral because the effect of L: mu upward arrow and D: mu downward arrow on the amino group should be similar in all alpha amino acids.
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30
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Fujiki M. Mirror symmetry breaking of silicon polymersâfrom weak bosons to artificial helix. CHEM REC 2009; 9:271-98. [DOI: 10.1002/tcr.200900018] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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31
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Nickel Complexes of Alanine Having a Preference for One Chiral Form over Another upon Crystallization. B KOREAN CHEM SOC 2009. [DOI: 10.5012/bkcs.2009.30.9.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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32
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Figgen D, Schwerdtfeger P. Structures, inversion barriers, and parity violation effects in chiral SeOXY molecules (X,Y=H, F, Cl, Br, or I). J Chem Phys 2009; 130:054306. [DOI: 10.1063/1.3072370] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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33
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Seo JH, Kim CS, Lee SP. Physicochemical Properties of Poly-γ-glutamic Acid Produced by a Novel Bacillus subtilis HA Isolated from Cheonggukjang. Prev Nutr Food Sci 2008. [DOI: 10.3746/jfn.2008.13.4.354] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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34
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Shinitzky M, Deamer D. Comments in a discussion: differential rates of D- and L-tyrosine crystallization. ORIGINS LIFE EVOL B 2008; 38:271-5. [PMID: 18351439 DOI: 10.1007/s11084-008-9129-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 02/09/2008] [Indexed: 11/26/2022]
Abstract
We earlier reported that we had observed quantifiable differences in crystallization rates of D and L tyrosine. It has been suggested that these results were due to the presence of impurities. Here we argue that it is premature to conclude that impurities entirely explain the results. More generally, there is an accumulating weight of evidence that D and L enantiomers display unexpected differences in their physical properties and behavior. These should be taken into account as we attempt to understand the origin of biochirality.
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Affiliation(s)
- Meir Shinitzky
- Department of Biochemistry, Weizmann Institute, Rehovot, Israel
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35
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Goldberg SI. Experimental evidence leading to an alternative explanation of why D-tyrosine sometimes crystallizes faster than its L-enantiomer. ORIGINS LIFE EVOL B 2008; 38:149-53. [PMID: 18219586 DOI: 10.1007/s11084-008-9123-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Accepted: 12/13/2007] [Indexed: 11/30/2022]
Abstract
On the occasions when D-tyrosine is observed to crystallize faster than its L-enantiomer, it is the result of a diastereomeric interaction between an airborne, non-racemic, chiral influence--probably a fungal spore--and the tyrosine enantiomers, enhancing the degree of crystal nucleation of D-tyrosine over L-tyrosine. This explanation, supported by experimental evidence, is presented as a more plausible alternative to the Shinitzky-Deamer hypothesis (Shinitzky et al., Progress in biological chirality, Elsevier, Amsterdam, pp. 329-337, 2004; Deamer et al., Chirality, 19:751-763, 2007) which relies on the parity violation energy difference between enantiomers, a femtojoule to picojoule per mole theoretical energy range.
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Affiliation(s)
- Stanley I Goldberg
- Department of Chemistry, University of New Orleans, 2000 Lakeshore Drive, New Orleans, LA 70148, USA.
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36
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Kodona EK, Alexopoulos C, Panou-Pomonis E, Pomonis PJ. Chirality and helix stability of polyglutamic acid enantiomers. J Colloid Interface Sci 2008; 319:72-80. [DOI: 10.1016/j.jcis.2007.10.063] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 10/30/2007] [Accepted: 10/30/2007] [Indexed: 11/24/2022]
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37
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Okhrimenko O, Jelesarov I. A survey of the year 2006 literature on applications of isothermal titration calorimetry. J Mol Recognit 2008; 21:1-19. [DOI: 10.1002/jmr.859] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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38
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Helix Generation, Amplification, Switching, and Memory of Chromophoric Polymers. Top Curr Chem (Cham) 2007. [DOI: 10.1007/128_2007_8] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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39
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Shinitzky M, Shvalb A, Elitzur AC, Mastai Y. Entrapped Energy in Chiral Solutions: Quantification and Information Capacity. J Phys Chem B 2007; 111:11004-8. [PMID: 17718467 DOI: 10.1021/jp072395f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A homogeneous solution of a chiral substance stores a residual chemical potential, related to its overall anisotropy. Therefore, by mixing solutions of opposite enantiomers, heat release may take place, corresponding to the mutual anisotropy annulment. In the following study we present proofs for this fundamental, yet unexplored, prediction by measuring the heat released upon mixing of aqueous solutions of D-proline with L-proline, as well as D-alanine with L-alanine, using isothermal titration calorimetry. Heat release in the range of 0.6-6 cal/mol was detected in these intermolecular racemizations at 30 degrees C. Its magnitude varied linearly with the apparent optical rotation, which complied with the possibility that the hydration envelope coating the chiral molecule is of a long-range condensed and asymmetrical configuration that can expand by integration with adjacent hydration envelopes. The ordered water in such hydration layers constitutes regions of "negative entropy", a basic medium for information storage. On the basis of our findings, a fundamental expression which combines entropy, information capacity, and thermal energy is proposed.
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Affiliation(s)
- Meir Shinitzky
- Department of Biological Chemistry, the Weizmann Institute of Science, Rehovot, 76100, Israel.
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40
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Shinitzky M, Elitzur AC. Ortho-para spin isomers of the protons in the methylene group--possible implications for protein structure. Chirality 2007; 18:754-6. [PMID: 16856167 DOI: 10.1002/chir.20319] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The two hydrogen atoms attached to the carbon in the methylene group are of two different spin configurations, similar to those in the case of water: ortho, where the two proton spins are parallel to each other, and para, where they are antiparallel. The ortho configuration has three degenerate states, while the para configuration is singular, leading to a statistical ratio of these isomers 3:1 ortho/para. Such spin isomers are present in glycine and most chiral amino acids where they may induce broadening of structural zones, a possibility which remains to be assessed. The implications of this neglected possibility could be far-reaching, in particular with respect to protein structure and the origins of biochirality.
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Affiliation(s)
- Meir Shinitzky
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel.
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41
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Deamer DW, Dick R, Thiemann W, Shinitzky M. Intrinsic asymmetries of amino acid enantiomers and their peptides: A possible role in the origin of biochirality. Chirality 2007; 19:751-63. [PMID: 17597118 DOI: 10.1002/chir.20434] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
L-amino acids and D-carbohydrates were incorporated into the first forms of life over 3.5 billion years ago, presumably from racemic mixtures of organic solutes produced by abiotic synthetic pathways. The process by which this choice occurred has not been established, but a consensus view is that it was a chance event, such that life could equally well have used D-amino acids and L sugars. In this review we will explore a second, less plausible alternative that minute differences in the physical properties of certain enantiomers made it more likely that L-amino acids and D-carbohydrates would be incorporated into early life. By all classical criteria, chiral isomers are perfect mirror image structures and, therefore, are expected to be identical in their macroscopic properties. However, scattered reports in the literature suggest that there may be slight differences in the physical properties of L- and D-amino acids and their polymers, which could lead to a preferred incorporation of L-amino acids into primitive forms of life. Here we present a literature survey of this issue and discuss its possible role in the origin of biochirality.
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Affiliation(s)
- David W Deamer
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA.
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42
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Reiner C, Nicholson GJ, Nagel U, Schurig V. Evaluation of enantioselective gas chromatography for the determination of minute deviations from racemic composition of α-amino acids with emphasis on tyrosine: Accuracy and precision of the method. Chirality 2007; 19:401-14. [PMID: 17385662 DOI: 10.1002/chir.20390] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Whereas the determination of high enantiomeric fractions (EF) of chiral compounds is very well established, the accurate determination of small deviations from racemic compositions has not yet received much attention despite its relevance to studies dealing with the origin of homochirality, where only small initial enantiomeric bias is expected. Racemic samples of representative alpha-amino acids were derivatized as N-(O,S)-trifluoroacetyl/ethylesters and analyzed by enantioselective gas chromatography (GC) on fused silica capillaries coated with the chiral stationary phases (CSPs) Chirasil-D-Val, Chirasil-L-Val, and Lipodex E with GC/FID and GC/MS detection. The validation (accuracy and precision) of the determination of the enantiomeric fraction EF of the D-enantiomer in racemic or near-racemic compositions for 10 DL-alpha-amino acids obtained from commercial sources has been carried out. Emphasis is given to DL-tyrosine, the enantiomers of which have recently been claimed to show different crystallization properties. Values of EF obtained from GC measurements using CSPs were compared with those from CE using chiral mobile phase additives. While the precision of the GC method is generally better than 0.08% for all DL-alpha-amino acids studied, accuracy (trueness) of determination of amino acids with polar side chains is poorer than expected from the precision as a result of systematic errors. The accuracy determined relied on measurements on two oppositely configurated CSPs.
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Affiliation(s)
- Clarissa Reiner
- Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen, Germany
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43
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Chandrasekhar S. Molecular homochirality and the parity-violating energy difference. A critique with new proposals. Chirality 2007; 20:84-95. [DOI: 10.1002/chir.20502] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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44
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Lahav M, Weissbuch I, Shavit E, Reiner C, Nicholson GJ, Schurig V. Parity violating energetic difference and enantiomorphous crystalsp-caveats; reinvestigation of tyrosine crystallization. ORIGINS LIFE EVOL B 2006; 36:151-70. [PMID: 16670821 DOI: 10.1007/s11084-005-9000-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Accepted: 09/07/2005] [Indexed: 11/28/2022]
Abstract
The present article challenges reports claiming to have demonstrated the Parity Violating Energetic Difference (PVED) between enantiomorphous D- and L-crystals. Apart from PVED, the presence of minute quantities and differing profiles of impurities incorporated during their different history of preparation will affect the physical properties of D- and L-crystals. These impurities are anticipated to play a much greater role in affecting crystallization behavior than PVED. The effect of impurities on the growth and dissolution of enantiomorphous crystals is illustrated with some representative examples. Shinitzky et al. (2002) reported recently dramatic differences in the growth and dissolution properties of the D- and L-crystals of tyrosine. We have repeated these experiments using commercial samples from different sources and employing a validated enantioselective gas chromatographic technique. We attribute Shinitzky's findings either to the use of inappropriate analytical techniques for the determination of enantiomeric composition and/or to the presence of unidentified contaminants in the commercial tyrosine samples. Related caveats hold also for the recently published claims by Shinitzky (2006) and Scolnik et al. (2006) to have observed experimentally PVED between enantiomeric helices of poly-glutamic acid composed of 24 repeating units.
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Affiliation(s)
- Meir Lahav
- Department of Materials and Interfaces, Weizmann Institute of Science, 76100 Rehovot, Israel.
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