Probing the interaction behavior of Nano-Resveratrol with α-lactalbumin in the presence of ß-lactoglobulin and ß-casein: spectroscopy and molecular simulation studies.

The main purpose of this research was to evaluate the role of α-lactalbumin (α-LA), ß-lactoglobulin (ß-LG), and ß-Caseins (ß-CN) in the binding interaction between Nano Resveratrol (Nano Res), as binary and ternary systems. This investigation was fulfilled through the application of multi-spectroscopic, transmission electron microscopy (TEM), field emission scanning electron microscope (FE-SEM), conductometry, isothermal titration calorimetry (ITC), and molecular dynamics (MD) simulation techniques. Fluorescence spectroscopy observations illustrated the effectiveness of Nano Res throughout the quenching of α-LA, (α-LA-ß-LG), and (α-LA-ß-CN) complexes, confirming the occurrence of interaction through the combination of static and dynamic mechanisms. An enhancement in the temperature of all three complexes caused a decrease in their Ksv and Kb values, which indicates the static and dynamic behavior of their interactions. The obtained thermodynamic parameters proved the dominance of electrostatic interaction as the binding force of both binary and ternary systems. The observed properties of Tyr or Trp residues in proteins through the data of synchronous spectroscopy at Δλ = 15 and 60 nm, respectively, demonstrated the closer positioning of (α-LA-ß-CN) complex to the proximity of Trp residues when compared to the two other cases. According to the resonance light scattering (RLS) measurements, the detection of a much greater RLS intensity in (α-LA-ß-CN) Nano Res complex suggested the production of a larger complex. Furthermore, the conductometry outcomes displayed an increase in molar conductivity and therefore approved the occurrence of interaction between Nano Res and proteins in both binary and ternary systems. The spherical shape of Nano Res was confirmed through the results of FE-SEM and TEM analyses. The conformational changes of proteins throughout the binding of Nano Res was evaluated by circular dichroism (CD) technique, while molecular docking and MD simulations affirmed the binding of Nano Res to α-LA, (α-LA-ß-LG), and (α-LA-ß-CN) complexes as binary and ternary systems. These In Silico study data confirm the results of in vitro assessments. The occurrence of changes in the secondary structure of ß-galactosidase was implied through the increased enzyme catalytic activity induced by the interaction of different lactose concentrations.Communicated by Ramaswamy H. Sarma.

New Perspective on the Interaction Behavior Between Riboflavin and ß Lactoglobulin-ß Casein Complex by Biophysical Techniques.

Riboflavin (RF) is a vitamin that only exists in plants and microorganisms and must be procured externally by humans. On the other hand, there are two major allergic factors in cow's milk, including ß-lactoglobulin (ßLG) and ß-casein (ßCN), while their allergic properties can be eliminated by binding to micronutrients. In this regard, we examined the binding process of RF to ßLG and ßCN in the binary and ternary systems by different spectroscopies such as zeta potential, electric conductivity, and molecular modeling. According to the result of the fluorescence spectrum regarding the interaction of RF with ßLG and ßCN in binary and ternary systems, an increase in RF concentration declined the fluorescence intensity of three systems and also caused the quenching of proteins. Static quenching plays a pivotal role in the formation of stable interactions. The obtained thermodynamic parameters by Van't Hoff equation ascertained the predominance of hydrogen bonds and van der Waals interaction in all the systems. Considering how the negative value of ΔH0 resulted in the negative value of ΔG0, the systems were assumed to be enthalpy driven. The outcomes of circular dichroism (CD) disclosed that the attachment of RF to the targets of systems increased their a-helix content, which particularly included the binding of RF to ßLG that led to the conversion of ß-sheet to α-helix content. As indicated by the results of zeta potential, the low concentration of RF contained the dominance of hydrophobic forces in the interactions, whereas the enlargement of this concentration prevailed electrostatic forces. Moreover, conductometry measurements showed an extension in the rate of ionizable groups due to the addition of RF to the systems, which may increase the probability of an interaction between RF, ßCN, and ßLG in binary and ternary systems. In consistency with the outcomes of molecular dynamics simulation, the data of molecular docking approved the capability of RF in forming strong and stable interactions with ßCN and ßLG.

Structure, Function, and Physicochemical Properties of Pore-forming Antimicrobial Peptides.

Antimicrobial peptides (AMPs), a class of antimicrobial agents, possess considerable potential to treat various microbial ailments. The broad range of activity and rare complete bacterial resistance to AMPs make them ideal candidates for commercial development. These peptides with widely varying compositions and sources share recurrent structural and functional features in mechanisms of action. Studying the mechanisms of AMP activity against bacteria may lead to the development of new antimicrobial agents that are more potent. Generally, AMPs are effective against bacteria by forming pores or disrupting membrane barriers. The important structural aspects of cytoplasmic membranes of pathogens and host cells will also be outlined to understand the selective antimicrobial actions. The antimicrobial activities of AMPs are related to multiple physicochemical properties, such as length, sequence, helicity, charge, hydrophobicity, amphipathicity, polar angle, and also self-association. These parameters are interrelated and need to be considered in combination. So, gathering the most relevant available information will help to design and choose the most effective AMPs.

Exploring the binding behavior mechanism of vitamin B12 to α-Casein and ß-Casein: multi-spectroscopy and molecular dynamic approaches.

The aim of this study was to investigate the behavior interaction of α-Casein-B12 and ß-Casein-B12 complexes as binary systems through the methods of multiple spectroscopic, zeta potential, calorimetric, and molecular dynamics (MD) simulation. Fluorescence spectroscopy denoted the role ofB12as a quencher in both cases of α-Casein and ß-Casein fluorescence intensities, which also verifies the existence of interactions. The quenching constants of α-Casein-B12 and ß-Casein-B12 complexes at 298 K in the first set of binding sites were 2.89 × 104 and 4.41 × 104 M-1, while the constants of second set of binding sites were 8.56 × 104 and 1.58 × 105 M-1, respectively. The data of synchronized fluorescence spectroscopy at Δλ = 60 nm were indicative of the closer location of ß-Casein-B12 complex to the Tyr residues. Additionally, the binding distance between B12 and the Trp residues of α-Casein and ß-Casein were obtained in accordance to the Förster's theory of nonradioactive energy transfer to be 1.95 nm and 1.85 nm, respectively. Relatively, the RLS results demonstrated the production of larger particles in both systems, while the outcomes of zeta potential confirmed the formation of α-Casein-B12 and ß-Casein-B12 complexes and approved the existence of electrostatic interactions. We also evaluated the thermodynamic parameters by considering the fluorescence data at three varying temperatures. According to the nonlinear Stern-Volmer plots of α-Casein and ß-Casein in the presence of B12 in binary systems, the two sets of binding sites indicated the detection of two types of interaction behaviors. Time-resolved fluorescence results revealed that the fluorescence quenching of complexes are static mechanism. Furthermore, the outcomes of circular dichroism (CD) represented the occurrence of conformational changes in α-Casein and ß-Casein upon their binding to B12 as the binary system. The experimental results that were obtained throughout the binding of α-Casein-B12 and ß-Casein-B12 complexes were confirmed by molecular modeling.Communicated by Ramaswamy H. Sarma.

Amino acid-mPEGs: Promising excipients to stabilize human growth hormone against aggregation.

Objectives: Today, the non-covalent PEGylation methods of protein pharmaceuticals attract more attention and possess several advantages over the covalent approach. In the present study, Amino Acid-mPEGs (aa-mPEGs) were synthesized, and the human Growth Hormone (hGH) stability profile was assessed in their presence and absence. Materials and Methods: aa-mPEGs were synthesized with different amino acids (Trp, Glu, Arg, Cys, and Leu) and molecular weights of polymers (2 and 5 KDa). The aa-mPEGs were analyzed with different methods. The physical and structural stabilities of hGH were analyzed by SEC and CD spectroscopy methods. Physical stability was assayed at different temperatures within certain intervals. Molecular dynamics (MD) simulation was used to realize the possible mode of interaction between protein and aa-mPEGs. The cell-based method was used to evaluate the cytotoxicity. Results: HNMR and FTIR spectroscopy indicated that aa-mPEGs were successfully synthesized. hGH as a control group is known to be stable at 4 °C; a pronounced change in monomer degradation is observed when stored at 25 °C and 37 °C. hGH:Glu-mPEG 2 kDa with a molar ratio of 1:1 to the protein solution can significantly increase the physical stability. The CD spectroscopy method showed that the secondary structure of the protein was preserved during storage. aa-mPEGs did not show any cytotoxicity activities. The results of MD simulations were in line with experimental results. Conclusion: This paper showed that aa-mPEGs are potent excipients in decreasing the aggregation of hGH. Glu-mPEG exhibited the best-stabilizing properties in a harsh environment among other aa-mPEGs.

Discovery of New Ligand with Quinoline Scaffold as Potent Allosteric Inhibitor of HIV-1 and Its Copper Complexes as a Powerful Catalyst for the Synthesis of Chiral Benzimidazole Derivatives, and in Silico Anti-HIV-1 Studies.

In this paper, the novel Schiff base ligand containing quinoline moiety and its novel copper chelate complexes were successfully prepared. The catalytic activity of the final complex in the organic reaction such as synthesis of chiral benzimidazoles and anti-HIV-1 activity of Schiff base ligand and the products of this reaction were investigated. In addition, green chemistry reactions using microwaves, powerful catalyst synthesis, green recovery and reusability, and separation of products with economic, safe, and clean methods (green chemistry) are among the advantages of this protocol. The potency of these compounds as anti-HIV-1 agents was investigated using molecular docking into integrase (IN) enzyme with code 1QS4 and the GROMACS software for molecular dynamics simulation. The final steps were evaluated in case of RMSD, RMSF, and Rg. The results revealed that the compound VII exhibit a good binding affinity to integrase (Δg = -10.99 kcal/mol) during 100 ns simulation time, and the analysis of RMSD suggested that compound VII was stable in the binding site of integrase.

Anti-quorum sensing and antibiofilm activity of coumarin derivatives against Pseudomonas aeruginosa PAO1: Insights from in vitro and in silico studies.

Objectives: Biofilm-associated infections are challenging to manage or treat since the biofilm matrix is impenetrable to most antibiotics. Therefore, the best approach to deal with biofilm infections is to interrupt the construction during the initial levels. Biofilm formation has been regulated through the quorum sensing (QS) network, making it an attractive target for any antibacterial therapy. Materials and Methods: Here, some coumarin members, including umbelliprenin, 4-farnesyloxycoumarin, gummosin, samarcandin, farnesifrol A, B, C, and auraptan, have been assessed as QS inhibitors in silico and in vitro. Their potential inhibitory effects on biofilm formation and virulence factor production of Pseudomonas aeruginosa PAO1 were evaluated. Results: First, the interaction of these compounds was investigated against one of the major transcriptional regulator proteins, PqsR, using molecular docking and structural analysis methodology. After that, in vitro evaluations indicated that 4-farnesyloxycoumarin and farnesifrol B showed considerable reduction in biofilm formation (62% and 56%, respectively), virulence factor production, and synergistic effects with tobramycin. Moreover, 4-farnesyloxycoumarin significantly (99.5%) reduced PqsR gene expression. Conclusion: The biofilm formation test, virulence factors production assays, gene expression analysis, and molecular dynamic simulations data demonstrated that coumarin derivatives are a potential anti-QS family through PqsR inhibition.

Multi spectroscopic and molecular simulation studies of propyl acridone binding to calf thymus DNA in the presence of electromagnetic force.

Introduction: Here, the interaction behavior between propyl acridones (PA) and calf thymus DNA (ct-DNA) has been investigated to attain the features of the binding behavior of PA with ct-DNA, which includes specific binding sites, modes, and constants. Furthermore, the effects of PA on the conformation of ct-DNA seem to be quite significant for comprehending the medicine's mechanism of action and pharmacokinetics. Methods: The project was accomplished through means of absorbance studies, fluorescence spectroscopy, circular dichroism, viscosity measurement, thermal melting, and molecular modeling techniques. Results: The intercalation of PA has been suggested by fluorescence quenching and viscosity measurements results while the thermal melting and circular dichroism studies have confirmed the thermal stabilization and conformational changes that seem to be associated with the binding. The binding constants of ct-DNA-PA complex, in the absence and presence of EMF, have been evaluated to be 6.19 × 104 M-1 and 2.95 × 104 M-1 at 298 K, respectively. In the absence of EMF, the ∆H0 and ∆S0 values that occur in the interaction process of PA with ct-DNA have been measured to be -11.81 kJ.mol-1 and 51.01 J.mol-1K-1, while in the presence of EMF they were observed to be -23.34 kJ.mol-1 and 7.49 J.mol-1K-1, respectively. These numbers indicate the involvement of multiple non-covalent interactions in the binding procedure. In a parallel study, DNA-PA interactions have been monitored by molecular dynamics simulations; their results have demonstrated DNA stability with increasing concentrations of PA, as well as calculated bindings of theoretical ΔG0. Conclusion: The complex formation between PA and ct-DNA has been investigated in the presence and absence of EMF through the multi spectroscopic techniques and MD simulation. These findings have been observed to be parallel to the results of KI and NaCl quenching studies, as well as the competitive displacement with EB and AO. According to thermodynamic parameters, electrostatic interactions stand as the main energy that binds PA to ct-DNA. Regarding the cases that involve the Tm of ct-DNA, EMF has proved to increase the stability of binding between PA and ct-DNA.

Molecular Dynamics and Multi-Spectroscopic of the Interaction Behavior between Bladder Cancer Cells and Calf Thymus DNA with Rebeccamycin: Apoptosis through the Down Regulation of PI3K/AKT Signaling Pathway.

The interaction of Rebeccamycin with calf thymus (ctDNA) in the absence and presence of H1 was investigated by molecular dynamics, multi-spectroscopic, and cellular techniques. According to fluorescence and circular dichroism spectroscopies, Rebeccamycin interacted with ctDNA in the absence of H1 through intercalator or binding modes, while the presence of H1 resulted in revealing theintercalator, as the dominant role, and groove binding modes of ctDNA-Rebeccamycin complex. The binding constants, which were calculated to be 1.22 × 104 M-1 and 7.92 × 105 M-1 in the absence and presence of H1, respectively, denoted the strong binding of Rebeccamycin with ctDNA. The binding constants of Rebeccamycin with ct DNA in the absence and presence of H1 were calculated at 298, 303 and 308 K. Considering the thermodynamic parameters (ΔH0 and ΔS0), both vander waals forces and hydrogen bonds played predominant roles throughout the binding of Rebeccamycin to ctDNA in the absence and presence of H1. The outcomes of circular dichroism suggested the lack of any major conformational changes in ctDNA upon interacting with Rebeccamycin, except some perturbations in native B-DNA at local level. Additionally, the effect of NaCl and KI on ctDNA-Rebeccamycin complex provided further evidence for the reliance of their interaction modes on substituted groups. The observed increase in the relative viscosity of ctDNA caused by the enhancement of Rebeccamycin confirmed their intercalation and groove binding modes in the absence and presence of H1. Moreover, the assessments of molecular docking simulation corroborated these experimental results and also elucidated the effectiveness of Rebeccamycinin inhibiting and proliferating T24 and 5637 cells. Meanwhile, the ability of Rebeccamycin in inhibiting cell proliferation and tumor growth through the induction of apoptosis by down regulating the PI3K/AKT signaling pathway were provided.

Understanding the binding behavior of Malathion with calf thymus DNA by spectroscopic, cell viability and molecular dynamics simulation techniques: binary and ternary systems comparison.

The interaction between calf thymus DNA (ctDNA) and Malathion in the absence and presence of Histone 1 has been enquired by the means of spectroscopic, viscometry, molecular modeling, and cell viability assay techniques. Malathion is capable of quenching the fluorescence of ct DNA in the absence and presence of H1. The binding constants of Malathion-ctDNA complex in the absence of H1 have been calculated to be 6.62 × 104, 4.31 × 104 and 1.93 × 104 M-1 at 298, 303, and 308 K, respectively that revealed static quenching in complex formation. The observed negative values of enthalpy and entropy changes indicate that the main binding interaction forces were van der Waals force and hydrogen bonding. The binding constant between Malathion and single-stranded ctDNA (ss ctDNA) seemed to be much weaker than that of Malathion and double-stranded ctDNA (ds ctDNA). Furthermore, Malathion can induce detectable alterations in the CD spectrum of ctDNA, along with changes in its viscosity. In the presence of H1, fluorescence quenching of ctDNA-Malathion complex displays dynamic behavior and binding constants were perceived to be 1.66 × 104, 2.93 × 104 and 5.77 × 104 M-1 at 298, 303, and 308 K, respectively. The different of interaction behavior between ctDNA and Malathion in the absence and presence of H1 clearly revealed H1 role in the complex formation and forces change between ctDNA and Malathion. The positive values of enthalpy and entropy changes have suggested that binding process is primarily driven by hydrophobic interactions. The tendency to interact with ss ctDNA, reduced viscosity have designated that the Malathion bound to ctDNA in the presence of H1 is groove binding. The results of molecular docking and molecular dynamics simulation also confirmed potent interactions between Malathion and the macromolecules in the binary and ternary systems.Communicated by Ramaswamy H. Sarma.

1,2,3,4,6-Pentagalloyl glucose of Pistacia lentiscus can inhibit the replication and transcription processes and viral pathogenesis of SARS-COV-2.

SARS-COV-2 stands as the source of the most catastrophic pandemic of this century, known as COVID-19. In this regard, we explored the effects of five Pistacia sp. active ingredients on the most crucial targets of SARS-COV-2, including 3CLpro, PLpro, RdRp, helicase, NSP15, and E protein. The results of molecular docking determined 1,2,3,4,6-pentagalloyl glucose (PG) as the most effective compound of Pistacia sp, which also confirmed its excellent binding affinities and stable interactions with helicase (-10.76 kcal/mol), RdRp (-10.19 kcal/mol), E protein (-9.51 kcal/mol), and 3CLpro (-9.47 kcal/mol). Furthermore, MD simulation was conducted to investigate the stability of all complexes throughout a 100 ns. In contrast to PLpro and NSP15, the analyses of Lennard-Jones potential, RMSDas, PCA, and SASA verified the ability of PG in forming stable and adequate interactions with RdRp, helicase, 3CLpro, and E protein due to standing as an effective inhibitor among the six targets, these data proposed the capability of PG, the most important compound of Pistacia sp., in inducing antiviral, anti-inflammatory, and antioxidant impacts on RdRp, helicase, 3CLpro, and E protein. Therefore, the possibility of inhibiting the replication and transcription processes and viral pathogenesis of SARS-COV-2 may be facilitated through the application of PG.

A novel vision into the binding behavior of curcumin with human serum albumin-holo transferrin complex: molecular dynamic simulation and multi-spectroscopic perspectives.

In this work, we investigated the simultaneous binding of curcumin (CUR) to human serum albumin (HSA) and human-holo transferrin (HTF) in the roles of binary and ternary systems. The binding affinity and binding site of protein-protein interaction were studied by the methods of multiple spectroscopic and molecular dynamics (MD) simulation. According to the results, the measurements for binding constant of HSA-CUR, HTF-CUR and (HSA-HTF) CUR complexes were observed to be 1.51 × 105, 7.93 × 104 and 1.44 × 105 M-1 respectively. Thermodynamic parameters were considered to be set at three varying temperatures including 298, 303, and 308 K. In conformity to the negative values of ΔH0 and ΔS0 the significant roles of hydrogen binding and van der-Waals forces in the formation of complexes are quiet evident. The binding distance between Trp residues of HSA, HTF and HSA-HTF upon interaction with CUR, were acquired by applying the Förster's theory of non-radioactive energy transfer and reported to be 2.04 nm, 1.78 nm, and 1.86 nm, respectively. In accordance with the conductometry and Resonance light scattering (RLS) results, there were different interaction behaviors among the HSA-HTF complex and CUR in ternary system when being compared to the outcomes of binary system. The secondary structure of all three cases increased as the CUR concentration was intensified, which confirmed the inducement of proteins conformational changes through the application of circular dichroism (CD) technique. The experimental results that were acquired throughout the binding of HSA-CUR, HTF-CUR, and (HSA-HTF) CUR complexes were approved by molecular modeling.Communicated by Ramaswamy H. Sarma.

Evaluation of the binding effect and cytotoxicity assay of 2-Ethyl-5-(4-methylphenyl) pyramido pyrazole ophthalazine trione on calf thymus DNA: spectroscopic, calorimetric, and molecular dynamics approaches.

With advances in new drug therapies, it is essential to understand the interactions between drugs and target molecules. In this study, we applied multiple spectroscopic techniques including absorbance, fluorescence, circular dichroism spectroscopy, viscosity, thermal melting, calorimetric, and molecular dynamics (MD) simulation to study the interaction between 2-Ethyl-5-(4-methylphenyl) pyramido pyrazole ophthalazine trione (PPF) and calf thymus DNA (ct DNA) in the absence or presence of histone H1. PPF exhibits a high binding affinity towards ct DNA in binary and ternary systems. In addition, the result for the binding constant was observed within the range 104 M-1 achieved through fluorescence quenching data, while the values for enthalpy and entropy changes for ct DNA-PPF and (ct DNA-H1) PPF complexes were measured to be -72.54 kJ.mol-1 , -161.14 J.mol-1  K-1 , -85.34 kJ.mol-1 , and -19.023 J.mol-1  K-1 , respectively. Furthermore, in accordance with circular dichroism spectra, the inducement of ct DNA structural changes was observed during binding of PPF and H1 in binary and ternary system forms. The essential roles of hydrogen bonding and van der Waals forces throughout the interaction were suggested using thermodynamic parameters. According to the obtained data, the interaction mode of ct DNA-PPF and (ct DNA-H1) PPF complexes was intercalation binding. Suggested by the MD simulation study, the ct DNA-H1 complex caused a reduction in the stability of the DNA structure in the presence or absence of ligand, which demonstrated that PPF as an intercalating agent can further distort the structure. The information achieved from this study will be very helpful in understanding the effects of PPF on the conformational state of ct DNA in the absence or presence of the H1 molecule, which seems to be quite significant for clarifying the mechanisms of action and its pharmacokinetics.

Determining the Interaction Behavior of Calf Thymus DNA with Anastrozole in the Presence of Histone H1: Spectroscopies and Cell Viability of MCF-7 Cell Line Investigations.

The interaction of calf thymus DNA (ct DNA) with anastrozole, which is acknowledged as an antineoplastic drug, has been enquired into in the absence and presence of histone H1, through the means of absorbance, fluorescence, circular dichroism spectroscopy, viscosity, thermal melting, and molecular modeling techniques. In addition, the effects of anastrozole on MCF 7 cell line have been thoroughly investigated. Fluorescence spectroscopy results have indicated that quenching mechanism of ct DNA-anastrozole are known as static quenching procedures, since the Stern-Volmer quenching constant (KSV) seems to face a decrease as the temperature is enhanced; this is a significant evidence for intercalative binding mode of anastrozole with ct DNA. Regarding the ternary system in the presence of H1, the constant of Stern-Volmer quenching was increased as the temperature was heightened. The thermodynamic parameters suggested that the binding could be characterized as exothermic by negative and positive enthalpy and entropy changes in both binary and ternary systems, respectively. It is vital to mention that hydrogen bonds and hydrophobic contributions play significant roles in anastrozole association to ct DNA in the absence and presence of H1. In accordance to the absorption spectroscopy and melting temperature curve outcomes, the binding mode of anastrozole with ct DNA in absence and presence of H1 was indicative of intercalative and nonintercalative bindings, respectively. The viscosity results as binary and ternary systems, which have been elucidated from a sensitive viscometer, have confirmed the fluorescence spectroscopy determinations. The intercalation of anastrozole to ct DNA seemed to be significantly related to an induced reduction in MCF-7 cell proliferation. The molecular modeling results have suggested that anastrozole could bind to H1 in ct DNA-H1 complex in ternary systems, which supports the conclusions that have been obtained from experimental data.

Description of the calf thymus DNA-malathion complex behavior by multi-spectroscopic and molecular modeling techniques: EMF at low and high frequency approaches.

OBJECTIVES: Small molecules can bind to DNA via covalent or non-covalent interactions, which results in altering or inhibiting the function of DNA. Thus, understanding the interaction patterns of medicines or other small molecules can be very crucial. In this study, the interaction between malathion and calf thymus DNA (ctDNA), in the absence and presence of electromagnetic field (EMF) at low and high frequencies, was investigated through various spectroscopies and viscosity measurements. MATERIALS AND METHODS: The interaction studies were performed by means of absorbance, circular dichroism, fluorescence spectroscopy, viscosity, thermal melting, and molecular modeling techniques. RESULTS: The fluorescence intensity of the ctDNA-malathion complex in the presence of EMF, has revealed quenching of fluorescence emission curves. The dynamic interaction and RLS studies have implied the changes in ctDNA-malathion complex throughout the presence of EMF which suggested that hydrophobic forces play the main role in the binding. Studies have revealed that malathion does not have any effect on binding ethidium bromide to ctDNA, which signifies the groove binding. The viscosity of ctDNA increased as the malathion concentration was enlarged. The circular dichroism technique suggested that the ellipticity values of the ctDNA-malathion complex have not increased with enhancing the malathion concentration. Molecular docking and dynamics studies have indicated a potent electrostatic interaction between ctDNA and malathion in the groove binding site. CONCLUSION: The results of spectroscopic studies reinforced a potent interaction between malathion and ctDNA in the absence and presence of EMF which can help us for further pharmaceutical drug discoveries.

Characterizing the Binding of Angiotensin Converting Enzyme I Inhibitory Peptide to Human Hemoglobin: Influence of Electromagnetic Fields.

BACKGROUND: Drug-protein complexes is one of the crucial factors when analyzing the pharmacokinetics and pharmacodynamics of a drug because they can affect the excretion, distribution, metabolism and interaction with target tissues. OBJECTIVES: The aim of this study was to investigate the interaction of human hemoglobin (Hb) and angiotensin I converting enzyme inhibitory peptide (ACEIP) in the absence and presence of different- frequency electromagnetic fields (EMF). METHODS: Various spectroscopic methods like fluorescence spectroscopy, ultraviolet, circular dichroism and conductometry techniques were applied to investigate Hb-ACEIP interaction in the absence and presence of EMF. RESULT: The presented spectroscopic studies indicated that EMF changed the interaction between Hb and ACEIP. The a-helix content of Hb decreased upon binding to ACEIP and conductivity of the solution enhanced upon binding. Based on Stern-Volmer equations, it could be stated that the Hb-ACEIP affinity was higher in the presence of EMF. CONCLUSION: It can be concluded that for patients who use the drug to control blood pressure, a low-frequency electromagnetic field would have a positive effect on the uptake of the drug.

Determining the interaction behavior of calf thymus DNA with berberine hydrochloride in the presence of linker histone: a biophysical study.

The binding of small molecules with histone-DNA complexes can cause an interference in vital cellular processes such as cell division and the growth of cancerous cells that results in apoptosis. It is significant to study the interaction of small molecules with histone-DNA complex for the purpose of better understanding their mechanism of action, as well as designing novel and more effective drug compounds. The fluorescence quenching of ct-DNA upon interaction with Berberine has determined the binding of Berberine to ct-DNA with Ksv = 9.46 × 107 M-1. Ksv value of ct-DNA-Berberine in the presence of H1 has been observed to be 3.10 × 107 M-1, indicating that the H1 has caused a reduction in the binding affinity of Berberine to ct-DNA. In the competitive emission spectrum, ethidium bromide (EB) and acridine orange (AO) have been examined as intercalators through the addition of Berberine to ct-DNA complexes, which includes ctDNA-EB and ctDNA-AO. Although in the presence of histone H1 , we have observed signs of competition through the induced changes within the emission spectra, yet there has been apparently no competition between the ligands and probes. The viscosity results have confirmed the different behaviors of interaction between ctDNA and Berberine throughout the binary and ternary systems. We have figured out the IC50 and viability percent values at three different time durations of interaction between Berberine and MCF7 cell line. The molecular experiments have been completed by achieving the results of MTT assay, which have been confirmed to be in good agreement with molecular modeling studies.Communicated by Ramaswamy H. Sarma.

A novel view of the separate and simultaneous binding effects of docetaxel and anastrozole with calf thymus DNA: Experimental and in silico approaches.

DNA stands as the primary purpose of many anticancer drugs and according to the performed research on this field, some certain changes contain crucial functionalities in the regulated transcription of DNA. Therefore, the interaction between anticancer drugs and DNA play an important role in understanding their function and also provide a better groundwork for producing more efficient and newer drugs. Here, the interaction between Docetaxel (DO) and calf thymus DNA (ct DNA), in the presence and absence of Anastrozole (AN), has been examined through the usage of different methods that include isothermal titration calorimetry, multi-spectroscopic, viscometry, and molecular docking techniques. Interaction studies have been performed by preparing different molar ratios of DO with the constant ct DNA and AN concentration at pH = 6.8. The binding constants have been calculated to be 7.93 × 104 M-1 and 6.27 × 104 M-1, which indicate the strong binding of DO with ct DNA double helix in the absence and presence of AN, respectively. Thermodynamic parameters, which were obtained from fluorescence spectroscopy and isothermal titration calorimetry, have suggested that the binding of DO and AN to ct DNA as binary and ternary systems have been mainly driven by the electrostatic interactions. The relative viscosity of ct DNA has increased upon the addition of DO and AN, which confirms the interaction mode. A competitive binding study has reported that the enhanced emission intensity of ethidium bromide (EB) and acridine orange (AO), in the presence of ct DNA, have been quenched through the addition of DO and Anastrozole as binary and ternary systems. As it is indicated by these findings, DO is capable of displacing EB and AO from their binding site in ct DNA; hence, it can be concluded that DO and AN are able to intercalate into the base pairs of ct DNA in binary and ternary systems. Molecular docking studies have corroborated the mentioned experimental results.

The immunotoxin activity of exotoxin A is sensitive to domain modifications.

Immunotoxins are a class of recombinant proteins which consist of an antibody and a part of a bacterial or herbal toxin. Immunotoxins containing Pseudomonas aeruginosa exotoxin A (PEA) have been found to be very applicable in clinical trials. Many obstacles such as solubility and absorbency reduce their usability in solid tumors. The current study aims to overcome the mentioned barriers by addition and removal of functional and non-functional domains with a structural approach. In the experimental section, we took advantage of molecular dynamics simulations to predict the functionality of candidate immunotoxins which target human HER2 receptors and confirmed our findings with in vitro experiments. We found out when no changes were made to domain II of PEA, addition of solubilizing domains to immunotoxins would not reduce their targeting and anti-tumor activity, while increasing the yield of expression and stability. On the other side, when we replaced domain II with eleven amino acids of furin cleavage site (FCS), the activity of the immunotoxin was mainly affected by the FCS neighboring domains and linkers. A combination of seven beneficial point mutations in domain III was also assessed and reconfirmed that the toxicity of the immunotoxin would be reduced dramatically. The obtained results indicate that the addition or removal of domains cannot depict the activity of immunotoxins and the matter should be assessed structurally in advance.

Design, Synthesis, and In Vitro Evaluation of Low Molecular Weight Protamine (LMWP)-Based Amphiphilic Conjugates as Gene Delivery Carriers.

Development of efficient non-viral carriers is one of the major challenges of gene delivery. In the current study, we designed, synthesized, and evaluated the in vitro gene delivery efficiency of novel amphiphilic constructs composed of cholesterol and low molecular weight protamine (LMWP: VSRRRRRRGGRRRR) peptide. Vectors having both hydrophobic and hydrophilic moieties were evaluated in terms of particle size and charge, DNA condensation ability, cytotoxicity, and gene transfection efficiency. The prepared vectors spontaneity self-assembled into the liposome-like particles with a high local positive density. The nano-vehicle A (H5-LMWP-Cholestrol) and nano-vehicle B (LMWP-Cholesterol) could form micelles at concentrations above 50 µg/mL and 65 µg/mL, respectively. The gel retardation assay showed that nano-vehicles A and B could condense pDNA more efficiently than the corresponding unconjugated peptides. The mean of size and zeta potential of complexed nano-vehicle A at N/P ratios of 5, 15, and 30 were 151 nm and 23 mv, and those of nano-vehicle B were 224 nm and 19 mv, respectively. In terms of transfection efficiency, the designed nano-vehicles showed almost two-fold higher gene expression level compared to PEI 25 kDa at optimal N/P ratios, and also exhibited negligible cytotoxicity on a model cancer cell, Neuro 2a. The findings of the present study revealed that these cationic micelles can be promising candidates as non-viral gene delivery vehicles.