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1.
Phys Chem Chem Phys ; 26(30): 20483-20489, 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39027987

RESUMO

We investigate the melting transition of non-supercoiled circular DNA of different lengths, employing Brownian dynamics simulations. In the absence of supercoiling, we find that melting of circular DNA is driven by a large bubble, which agrees with the previous predictions of circular DNA melting in the presence of supercoiling. By analyzing sector-wise changes in average base-pair distance, our study reveals that the melting behavior of circular DNA closely resembles that of linear DNA. Additionally, we find a marked difference in the thermal stability of circular DNA over linear DNA at very short length scales, an effect that diminishes as the length of circular DNA increases. The stability of smaller circular DNA is linked to the occurrence of transient small bubbles, characterized by a lower probability of growth.


Assuntos
DNA Circular , Desnaturação de Ácido Nucleico , DNA Circular/química , Conformação de Ácido Nucleico , Simulação de Dinâmica Molecular , Temperatura de Transição , DNA/química , Termodinâmica
2.
Funct Integr Genomics ; 23(1): 51, 2023 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-36707443

RESUMO

Tropical rainforests in Southeast Asia are enriched by multifarious biota dominated by Dipterocarpaceae. In this family, Shorea robusta is an ecologically sensitive and economically important timber species whose genomic diversity and phylogeny remain understudied due to lack of datasets on genetic resources. Smattering availability of molecular markers impedes population genetic studies indicating a necessity to develop genomic databases and species-specific markers in S. robusta. Accordingly, the present study focused on fostering de novo low-depth genome sequencing, identification of reliable microsatellites markers, and their validation in various populations of S. robusta in Uttarakhand Himalayas. With 69.88 million raw reads assembled into 1,97,489 contigs (read mapped to 93.2%) and a genome size of 357.11 Mb (29 × coverage), Illumina paired-end sequencing technology arranged a library of sequence data of ~ 10 gigabases (Gb). From 57,702 microsatellite repeats, a total of 35,049 simple sequence repeat (SSR) primer pairs were developed. Afterward, among randomly selected 60 primer pairs, 50 showed successful amplification and 24 were found as polymorphic. Out of which, nine polymorphic loci were further used for genetic analysis in 16 genotypes each from three different geographical locations of Uttarakhand (India). Prominently, the average number of alleles per locus (Na), observed heterozygosity (Ho), expected heterozygosity (He), and the polymorphism information content (PIC) were recorded as 2.44, 0.324, 0.277 and 0.252, respectively. The accessibility of sequence information and novel SSR markers potentially enriches the current knowledge of the genomic background for S. robusta and to be utilized in various genetic studies in species under tribe Shoreae.


Assuntos
Dipterocarpaceae , Genoma de Planta , Dipterocarpaceae/genética , Repetições de Microssatélites , Polimorfismo Genético
3.
Nucleic Acids Res ; 48(4): 1701-1714, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-31919510

RESUMO

Replication protein A (RPA) plays a critical role in all eukaryotic DNA processing involving single-stranded DNA (ssDNA). Contrary to the notion that RPA provides solely inert protection to transiently formed ssDNA, the RPA-ssDNA complex acts as a dynamic DNA processing unit. Here, we studied the diffusion of RPA along 60 nt ssDNA using a coarse-grained model in which the ssDNA-RPA interface was modeled by both aromatic and electrostatic interactions. Our study provides direct evidence of bulge formation during the diffusion of ssDNA along RPA. Bulges can form at a few sites along the interface and store 1-7 nt of ssDNA whose release, upon bulge dissolution, leads to propagation of ssDNA diffusion. These findings thus support the reptation mechanism, which involves bulge formation linked to the aromatic interactions, whose short range nature reduces cooperativity in ssDNA diffusion. Greater cooperativity and a larger diffusion coefficient for ssDNA diffusion along RPA are observed for RPA variants with weaker aromatic interactions and for interfaces homogenously stabilized by electrostatic interactions. ssDNA propagation in the latter instance is characterized by lower probabilities of bulge formation; thus, it may fit the sliding-without-bulge model better than the reptation model. Thus, the reptation mechanism allows ssDNA mobility despite the extensive and high affinity interface of RPA with ssDNA. The short-range aromatic interactions support bulge formation while the long-range electrostatic interactions support the release of the stored excess ssDNA in the bulge and thus the overall diffusion.


Assuntos
Replicação do DNA/genética , DNA de Cadeia Simples/genética , Proteínas de Ligação a DNA/genética , Proteína de Replicação A/genética , Estruturas Cromossômicas/genética , DNA de Cadeia Simples/química , Proteínas de Ligação a DNA/química , Humanos , Ligação Proteica/genética , Proteína de Replicação A/química
4.
Transfus Apher Sci ; 60(4): 103142, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33962886

RESUMO

BACKGROUND: RhD expression varies with population and ethnicity. Accurate typing of RhD antigen among blood donors is important to prevent development of anti-D among recipients of blood transfusion. We aimed to screen blood donors for variant D phenotypes and accurately characterize them by genotyping. MATERIAL AND METHODS: We have done prospective study on blood donors by performing RhD typing using three different commercial monoclonal anti-D reagents by both column agglutination and conventional tube techniques. Samples that showed ambiguous results were further screened with the Bio-Rad Partial RhD typing kit. Minor phenotyping for C, c, E, e antigens was performed. Multiplex PCR and Sequencing of all RHD exons with Sanger's sequencing was performed for molecular characterization of variant D. RESULTS: A total of 16,974 blood donors were screened during the study period. Among them, 31 (0.18 %) donors were found to have a RhD variant phenotype. The male to female ratio was 10:1. The presence of 'C' antigen was noted among all RhD variant samples. Serological typing identified two samples as DV phenotype and the rest could not be characterized. Molecular genotyping characterized 90.3 % of the samples as Indian specific weak D type 150 variants. Three samples were subjected to Sangers sequencing and showed wild type pattern. CONCLUSION: The present study showed that the most common variant in this population was Weak D type 150. This study highlights that serological methods may serve as a screening tool, however, molecular techniques are essential for characterization of RhD variants.


Assuntos
Doadores de Sangue , Variação Genética , Sistema do Grupo Sanguíneo Rh-Hr/genética , Feminino , Humanos , Índia , Masculino , Estudos Prospectivos , Análise de Sequência de DNA
5.
Transfus Apher Sci ; 60(3): 103109, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33752990

RESUMO

Unusual Rh phenotypes such as Rhnull, D-- and Dc- etc. are rarely encountered in routine blood bank testing. The Rhnull phenotype is characterized by the absence of all Rh antigens, D-- phenotype does not express any RhCcEe antigens whereas Dc- phenotype individual lacks expression of antithetical E /e antigens. These individuals may produce multiple Rh antibodies against missing antigens. An old woman (B RhD positive) from Bangladesh with end-stage renal disease developed severe anaemia. Cross-matching with ABO and RhD compatible blood units showed +3 agglutination reaction. Detailed immunohaematological investigations showed a lack of C, E and e antigens, thus identifying the rare Rh variant as Dc-. Antibodies against C and e antigens were also detected in the patient's serum. PCR-SSP confirmed the absence of the molecular region defining the C, E and e antigens. Copy number analysis by QMPSF revealed the homozygous state of (RHCE-D(4-9)-CE) allele at the RHCE gene locus. This is the first report of the rare Dc- variant individual from the Indian subcontinent.


Assuntos
Sistema do Grupo Sanguíneo Rh-Hr/genética , Feminino , Humanos , Índia , Pessoa de Meia-Idade , Fenótipo
6.
Transfus Med ; 31(5): 383-386, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34121248

RESUMO

BACKGROUND: D antigen is one among the most immunogenic antigens and is the most common cause of Haemolytic Disease of Fetus and Newborn (HDFN). The D-phenotype is a rare Rh variant in which none of the RhCE antigens are expressed on the red cell surface. Individuals having D-phenotype are capable of producing a rare alloantibody named as anti-Rh17(Hr° ) in response to pregnancy or transfusion and has the potential to react with C/c and E/e antigens causing severe haemolytic transfusion reaction (HTR) and haemolytic disease of fetus and newborn (HDFN). CASE REPORT: We have encountered a case of severe HDFN with an accidental discovery of D- phenotype of the mother with anti-Rh-17 antibodies. D- phenotype has been confirmed with molecular typing along with genotyping of all family members. CONCLUSION: Rare phenotypes like D- individuals especially if allo-immunised are of great concern at times of transfusion requirements. Hence, proper identification of these individuals are important to contribute them to the rare donor pool and to adopt adequate patient blood management strategies.


Assuntos
Eritroblastose Fetal , Sistema do Grupo Sanguíneo Rh-Hr , Eritroblastose Fetal/genética , Eritroblastose Fetal/terapia , Eritrócitos , Feminino , Feto , Humanos , Fenótipo , Gravidez , Sistema do Grupo Sanguíneo Rh-Hr/genética
7.
Proc Natl Acad Sci U S A ; 112(16): 5033-8, 2015 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-25855635

RESUMO

ssDNA binding proteins (SSBs) protect ssDNA from chemical and enzymatic assault that can derail DNA processing machinery. Complexes between SSBs and ssDNA are often highly stable, but predicting their structures is challenging, mostly because of the inherent flexibility of ssDNA and the geometric and energetic complexity of the interfaces that it forms. Here, we report a newly developed coarse-grained model to predict the structure of SSB-ssDNA complexes. The model is successfully applied to predict the binding modes of six SSBs with ssDNA strands of lengths of 6-65 nt. In addition to charge-charge interactions (which are often central to governing protein interactions with nucleic acids by means of electrostatic complementarity), an essential energetic term to predict SSB-ssDNA complexes is the interactions between aromatic residues and DNA bases. For some systems, flexibility is required from not only the ssDNA but also, the SSB to allow it to undergo conformational changes and the penetration of the ssDNA into its binding pocket. The association mechanisms can be quite varied, and in several cases, they involve the ssDNA sliding along the protein surface. The binding mechanism suggests that coarse-grained models are appropriate to study the motion of SSBs along ssDNA, which is expected to be central to the function carried out by the SSBs.


Assuntos
DNA de Cadeia Simples/química , DNA de Cadeia Simples/metabolismo , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Modelos Moleculares , Ligação Proteica , Proteína de Replicação A/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Eletricidade Estática , Termodinâmica
8.
Transfus Med Hemother ; 45(3): 173-177, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29928172

RESUMO

BACKGROUND: Molecular bases of blood group systems, including Rh blood group, have been poorly studied in the Indian population so far, while specificities of Europeans, East Asians and Africans have been well known for years. In order to gain insights into the molecular bases of this population, we sought to characterize the RHD allele in D- Indian donors expressing C and/or E antigen(s). METHODS: RHD gene was analyzed in 171 serologically D-, C/E+ samples by standard molecular methods such as quantitative, multiplex PCR of short fluorescent fragments (QMPSF) and direct sequencing when necessary. RESULTS: RHD whole gene deletion at the homozygous state was found to be the most common genotype associated with D- phenotype (118/171, 69.0%). Nonfunctional, negative hybrid genes with reported molecular backgrounds were observed in approximately one-third of the samples, while only four samples carry single-nucleotide variations, including one novel nonsense (RHD(Y243X)), one novel frameshift (RHD(c.701delG)), and two missense (RHD(T148R) and RHD(T148R, T195M)) alleles. CONCLUSION: Overall we report for the first time the molecular bases of D antigen negativity in the D-, C/E+ Indian population, which appears to be qualitatively similar to other populations, but with a population-specific, quantitative distribution of D-- alleles.

10.
Phys Rev E ; 109(2-1): 024409, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38491671

RESUMO

We determine the phase diagram of DNA with inter- and intrastrand native-pair interactions that mimic the compaction of DNA. We show that DNA takes an overall sheetlike structure in the region where an incipient transition to a compact phase would have occurred. The stability of this phase is due to the extra entropy from the folding of the sheet, which is absent in the remaining polymerlike states of the phase diagram.


Assuntos
Dobramento de Proteína , Entropia , Termodinâmica
11.
J Mol Biol ; 436(6): 168491, 2024 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-38360091

RESUMO

Replication Protein A (RPA) is asingle strandedDNA(ssDNA)binding protein that coordinates diverse DNA metabolic processes including DNA replication, repair, and recombination. RPA is a heterotrimeric protein with six functional oligosaccharide/oligonucleotide (OB) domains and flexible linkers. Flexibility enables RPA to adopt multiple configurations andis thought to modulate its function. Here, usingsingle moleculeconfocal fluorescencemicroscopy combinedwith optical tweezers and coarse-grained molecular dynamics simulations, we investigated the diffusional migration of single RPA molecules on ssDNA undertension.The diffusioncoefficientDis the highest (20,000nucleotides2/s) at 3pNtension and in 100 mMKCl and markedly decreases whentensionor salt concentrationincreases. We attribute the tension effect to intersegmental transfer which is hindered by DNA stretching and the salt effect to an increase in binding site size and interaction energy of RPA-ssDNA. Our integrative study allowed us to estimate the size and frequency of intersegmental transfer events that occur through transient bridging of distant sites on DNA by multiple binding sites on RPA. Interestingly, deletion of RPA trimeric core still allowed significant ssDNA binding although the reduced contact area made RPA 15-fold more mobile. Finally, we characterized the effect of RPA crowding on RPA migration. These findings reveal how the high affinity RPA-ssDNA interactions are remodeled to yield access, a key step in several DNA metabolic processes.


Assuntos
DNA de Cadeia Simples , Proteína de Replicação A , Replicação do DNA , DNA de Cadeia Simples/química , DNA de Cadeia Simples/metabolismo , Ligação Proteica/genética , Proteína de Replicação A/química , Proteína de Replicação A/genética , Proteína de Replicação A/metabolismo
12.
Phys Rev Lett ; 110(25): 258102, 2013 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-23829761

RESUMO

A simple model of DNA based on two interacting polymers has been used to study the unzipping of a double stranded DNA subjected to a periodic force. We propose a dynamical transition where, without changing the physiological condition, it is possible to bring DNA from the zipped or unzipped state to a new dynamic (hysteretic) state by varying the frequency of the applied force. Our studies reveal that the area of the hysteresis loop grows with the same exponents as of the isotropic spin systems. These exponents are amenable to verification in the force spectroscopic experiments.


Assuntos
DNA de Cadeia Simples/química , DNA/química , Modelos Químicos , DNA/biossíntese , DNA/fisiologia , Replicação do DNA , DNA de Cadeia Simples/metabolismo , DNA de Cadeia Simples/fisiologia , Concentração de Íons de Hidrogênio , Conformação de Ácido Nucleico , Temperatura , Termodinâmica
13.
J Chem Phys ; 138(24): 244905, 2013 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-23822272

RESUMO

Using Langevin dynamics simulations, we study a simple model of interacting-polymer under a periodic force. The extension curves strongly depend on the magnitude of the amplitude (F) and the frequency (ν) of the applied force. In low frequency limit, the system retraces the thermodynamic path. At higher frequencies, response time is greater than the external time scale for change of force, which restrict the biomolecule to explore a smaller region of phase space that results in hysteresis of different shapes and sizes. We show the existence of dynamical transition, where area of hysteresis loop approaches to a large value from nearly zero value with decreasing frequency. The area of hysteresis loop is found to scale as F(α)ν(ß) for the fixed length. These exponents are found to be the same as of the mean field values for a time dependent hysteretic response to periodic force in case of the isotropic spin.


Assuntos
DNA/química , Simulação de Dinâmica Molecular , Polímeros/química , Termodinâmica
14.
Phys Rev E ; 108(4): L042501, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37978702

RESUMO

Using Langevin dynamic simulations, a simple coarse-grained model of a DNA protein construct is used to study the DNA rupture and the protein unfolding. We identify three distinct states: (i) zipped DNA and collapsed protein, (ii) unzipped DNA and stretched protein, and (iii) unzipped DNA and collapsed protein. Here, we find a phase diagram that shows these states depending on the size of the DNA handle and the protein. For a less stable protein, unfolding is solely governed by the size of the linker DNA, whereas if the protein's stability increases, complete unfolding becomes impossible because the rupture force for DNA has reached a saturation regime influenced by the de Gennes length. We show that unfolding occurs via a few intermediate states by monitoring the force-extension curve of the entire protein. We extend our study to a heterogeneous protein system, where similar intermediate states in two systems can lead to different protein unfolding paths.


Assuntos
Desdobramento de Proteína , Proteínas , DNA
15.
Biol Methods Protoc ; 8(1): bpad039, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38116323

RESUMO

Shorea robusta (Dipterocarpaceae), commonly known as Sal, is an economically and culturally important timber species, known to contain a wide spectrum of polyphenols, polysaccharides, and other secondary metabolites in the tissues, which can interfere with the extraction of high-quality genomic DNA. In order to screen simple sequence repeat (SSR) markers and carry out other DNA-based analyses for this species in our laboratory, a high-throughput DNA extraction methodology was needed. Hence, we have optimized a simple, rapid, safe, and reliable high-throughput protocol for DNA extraction suitable for both fresh and dry leaves. The standardized protocol delivered good DNA yield of ∼1500 µg from 1 g of leaf tissue, with purity indicated by a 260 nm/280 nm absorbance ratio ranging from 1.70 to 1.91, which validated the suitability of extracted DNA and revealed reduced levels of contaminants. Additionally, the protocol that we developed was found to be suitable for polymerase chain reaction (PCR) amplification using microsatellite markers. Genome-wide characterization with SSR markers has been established in S. robusta, which further validates the protocol and its usefulness in DNA-based studies across the genus and/or family.

16.
Front Pharmacol ; 14: 1212742, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37361234

RESUMO

In the current scenario, prolonged consumption of alcohol across the globe is upsurging an appreciable number of patients with the risk of alcohol-associated liver diseases. According to the recent report, the gut-liver axis is crucial in the progression of alcohol-induced liver diseases, including steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Despite several factors associated with alcoholic liver diseases, the complexity of the gut microflora and its great interaction with the liver have become a fascinating area for researchers due to the high exposure of the liver to free radicals, bacterial endotoxins, lipopolysaccharides, inflammatory markers, etc. Undoubtedly, alcohol-induced gut microbiota imbalance stimulates dysbiosis, disrupts the intestinal barrier function, and trigger immune as well as inflammatory responses which further aggravate hepatic injury. Since currently available drugs to mitigate liver disorders have significant side effects, hence, probiotics have been widely researched to alleviate alcohol-associated liver diseases and to improve liver health. A broad range of probiotic bacteria like Lactobacillus, Bifidobacteria, Escherichia coli, Sacchromyces, and Lactococcus are used to reduce or halt the progression of alcohol-associated liver diseases. Several underlying mechanisms, including alteration of the gut microbiome, modulation of intestinal barrier function and immune response, reduction in the level of endotoxins, and bacterial translocation, have been implicated through which probiotics can effectively suppress the occurrence of alcohol-induced liver disorders. This review addresses the therapeutic applications of probiotics in the treatment of alcohol-associated liver diseases. Novel insights into the mechanisms by which probiotics prevent alcohol-associated liver diseases have also been elaborated.

17.
Nat Prod Res ; 36(24): 6259-6266, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35045783

RESUMO

The first synthetic route of naturally occurring (±)-5,7-dihydroxy-8-methyl-3-(2',4'-dihydroxybenzyl)chroman-4-one (1) from Gan Luo Xin pill was successfully accomplished. The synthetic route has been developed retro-synthetically in 9 simple steps with a high yield of ∼80%. The synthetic protocol was developed using readily available starting material phloroglucinol. The key intermediate 2,4,6-trihydroxy-3-methyl acetophenone (4) was synthesized via Vilsmeier-Haack reaction, followed by reduction using sodium cyanoborohydride and acylation reaction. LC-MS, IR, 1H NMR, 13C NMR of 1 have been analyzed to confirm the structure of (±)-5,7-dihydroxy-8-methyl-3-(2',4'-dihydroxybenzyl)chroman-4-one (1) and found in agreement with the natural molecule. The target compound showed 97% and 87% antioxidant activity in DPPH and ABTS assay at 1 mg/ml concentration, respectively. The compound (1) also showed ferric ion reducing activity with the absorbance of 0.18 at 700 nm. The present study could be useful in developing synthetic routes of other potential naturally occurring homoisoflavonoid.


Assuntos
Produtos Biológicos , Medicina Tradicional do Leste Asiático , Antioxidantes/farmacologia
18.
Blood Transfus ; 20(1): 59-65, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-33263520

RESUMO

BACKGROUND: Rh antigens are critical in haemolytic disease of the foetus and newborn (HDFN). The D-- phenotype is a rare blood group characterised by the lack of expression of C, c, E and e antigens at the surface of red blood cells because of mutations in both RHCE alleles inactivating the expression of a "normal" protein. The aim of the study was to determine the molecular basis of D-- individuals of Indian origin. MATERIALS AND METHODS: Ten Rh D-positive postnatal women who had produced antibodies against all Rh antigens, except D, leading to HDFN and foetal loss, were investigated. Extensive serological and molecular (polymerase chain reaction [PCR] using sequence-specific primers), quantitative multiplex PCR of short fluorescent fragments (QMPSF), and Sanger sequencing analyses were carried out. RESULTS: Serological testing with anti-C, anti-c, anti-E, and anti-e reagents showed absence of the four antigens in all ten index cases, as well as in three siblings. Flow cytometry indicated absence of these antigens with a typical exalted expression of the D antigen, thus confirming the rare D-- phenotype. Molecular analysis by QMPSF suggested homozygous CE-D hybrid alleles causing the D-- phenotype: RHCE-D(3-9)-CE (n = 11), RHCE-D(3-8)-CE (n=1), and RHCE-D(2-6)-CE (n=1). DISCUSSION: For the first time, we report the molecular basis of the D-- phenotype in the Indian population. Identification and characterisation of RHCE-null variants by molecular methods can help resolve transfusion-related problems in these individuals. Family studies of index cases helped to identify rare blood donors and offer counselling to females of child-bearing age on the complications involved in such pregnancies.


Assuntos
Antígenos de Grupos Sanguíneos , Eritroblastose Fetal , Alelos , Antígenos de Grupos Sanguíneos/genética , Eritroblastose Fetal/genética , Feminino , Humanos , Fenótipo , Gravidez , Sistema do Grupo Sanguíneo Rh-Hr/genética
19.
J Chem Phys ; 135(3): 035102, 2011 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-21787024

RESUMO

Dynamics of a single stranded DNA, which can form a hairpin have been studied in the constant force ensemble. Using Langevin dynamics simulations, we obtained the force-temperature diagram, which differs from the theoretical prediction based on the lattice model. Probability analysis of the extreme bases of the stem revealed that at high temperature, the hairpin to coil transition is entropy dominated and the loop contributes significantly in its opening. However, at low temperature, the transition is force driven and the hairpin opens from the stem side. It is shown that the elastic energy plays a crucial role at high force. As a result, the force-temperature diagram differs significantly with the theoretical prediction.


Assuntos
DNA/química , Entropia , Simulação de Dinâmica Molecular
20.
Sci Adv ; 6(31): eaaw8331, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32789165

RESUMO

Lyotropic cholesteric liquid crystal phases are ubiquitously observed in biological and synthetic polymer solutions, characterized by a complex interplay between thermal fluctuations and entropic and enthalpic forces. The elucidation of the link between microscopic features and macroscopic chiral structure, and of the relative roles of these competing contributions on phase organization, remains a topical issue. Here, we provide theoretical evidence of a previously unidentified mechanism of chirality amplification in lyotropic liquid crystals, whereby phase chirality is governed by fluctuation-stabilized helical deformations in the conformations of their constituent molecules. Our results compare favorably to recent experimental studies of DNA origami assemblies and demonstrate the influence of intramolecular mechanics on chiral supramolecular order, with potential implications for a broad class of experimentally relevant colloidal systems.


Assuntos
Cristais Líquidos , DNA/química , Cristais Líquidos/química , Conformação Molecular , Polímeros , Termodinâmica
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