Structure Of Bovine Hemoglobin Research Articles

The Effect of Glucose on the Interaction of Bisphenol A and Bovine Hemoglobin Characterized by Spectroscopic and Molecular Docking Techniques.

The interaction mechanism of hemoglobin (Hb) with bisphenol A (BPA) in diabetic patients and the difference with healthy people have been studied using spectroscopic and molecular docking techniques at several glucose (Glc) concentration, with bovine hemoglobin (BHb) instead of Hb. It is found that Glc can interact with BHb-BPA and affect its molecular structure, resulting in an altered microenvironment for tyrosine (Tyr) and tryptophan (Trp) in BHb-BPA. It is also found that Glc can bind to BHb alone, and its effect on the molecular structure of BHb is weaker than that on the structure of BHb in BHb-BPA complex. The results of circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) indicate that Glc causes an increase in the content of the α-helix and a decrease in that of the β-sheet of BHb-BPA by 1.5-1.9% and 3.1%, respectively. The results of molecular docking show that Glc binds to BHb-BPA through hydrogen and hydrophobic bonds, and the position of binding differs from that of Glc binding to BHb alone, which may be attributed to the fact that BPA affects the protein molecular structure of BHb and has an effect on the binding of BHb to Glc. This study provides some theoretical basis for the mechanism of BPA toxicity in vivo for people with different blood glucose levels.

A comprehensive in vitro exploration into the interaction mechanism of coumarin derivatives with bovine hemoglobin: Spectroscopic and computational methods

Biological functioning takes place through the interaction of biomacromolecules with each other or with other small molecules. The molecular recognition of a carrier protein, bovine hemoglobin (BHb), with 7-hydroxycoumarin (7-HC) and 4-methyl-7-hydroxycoumarin (4-Me-7-HC) was investigated using various biophysical and computational techniques. Fluorescence spectroscopy and molecular docking revealed the interaction of 7-HC and 4-Me-7-HC with β2-Trp37 fluorophore, quenching the intrinsic fluorescence of BHb. The mechanism of quenching was determined to be static. The binding constant (Kb) for BHb with 7-HC and 4-Me-7-HC was found to be 6.15 × 104 M−1 and 5.73 × 104 M−1 at 298 K, respectively. This moderate form of protein–ligand association could result in reversible binding to transport and release the ligand in the target tissue. Negative ΔG for both complexes suggested spontaneous binding. Positive ΔH and ΔS for BHb-7-HC indicated hydrophobic forces played a dominant role in binding. However, hydrogen bonding and hydrophobic forces dictated the binding process for BHb-4-Me-7-HC due to obtaining negative ΔH and positive ΔS values. Changes in the microenvironment of the binding site were observed through 3D fluorescence studies. Through Förster resonance energy transfer (FRET), a binding distance of less than 7 nm was measured between BHb and 7-HC/4-Me-7-HC. The interaction of coumarin derivatives with BHb resulted in a loss of α-helical content of the protein, as proven by circular dichroism (CD) and Fourier transform infrared (FTIR) measurements. Molecular dynamic simulations showed the binding of 7-HC supplemented the stability of BHb, whereas 4-Me-7-HC binding resulted in conformational changes in the structure of BHb.

Understanding the structure and conformation of bovine hemoglobin in presence of the drug hydroxyurea: multi-spectroscopic studies supported by docking and molecular dynamics simulation

Binding interaction between the small antitumor drug Hydroxyurea (HU) and Bovine Hemoglobin (BHb) has been explored in details from multi-spectroscopic and computational studies. The formation of ground state complex between BHb and HU has been suggested from the electronic UV–Vis and steady-state fluorescence spectroscopic studies. The quenching in fluorescence of BHb in presence of HU at varied concentrations has been analyzed from the SV plots. Static type of quenching has been suggested from time-resolved fluorescence spectroscopic studies. Binding parameters associated with the BHb-HU complex have also been estimated from the temperature dependent fluorescence spectroscopic studies. Alterations in the micro-environment of the Tyr and Trp residues of BHb in presence of HU have been observed from the synchronous fluorescence measurement. The result obtained from CD spectroscopic measurements signify partial unfolding in the secondary structure of BHb due to binding with HU molecule. The experimental observations are supported by theoretical studies. Molecular docking and molecular dynamics simulations have been performed to investigate the structural stability and compactness of BHb in the binding interaction between BHb and HU. The interaction of BHb with HU is expected to provide fundamental insights towards understanding the therapeutic effectiveness of HU upon interaction with BHb used in chemo-, radio therpeutic procedures and also in the treatment of SCD.

Bovine hemoglobin adsorption onto modified silica nanoparticles: Multi-spectroscopic measurements based on kinetics and protein conformation

Herein, the effects of bovine hemoglobin (BHb) binding to hydrophilic silica nanoparticles (SN1) and hydrophobic silica nanoparticles (SN2) were explored under physiological conditions. SEM and XRD were used to characterize silica nanoparticles (SNs). Zeta potential and DLS confirmed the formation of protein corona (PC), and SN2 showed more increase in their size after PC formation comparing with SN1. The adsorption isotherms were fitted well by the Freundlich model, and the kinetics tended to follow pseudo-second-order kinetics. Then, the second structure of BHb has been analyzed by UV–vis and FT-IR spectroscopy, which implied the impact of SN2 on the secondary structure of BHb was greater than that of SN1 on BHb. Moreover, fluorescence spectroscopy and Raman spectroscopy showed that SNs may induce heme degradation to form fluorescent heme product, resulting in increased fluorescence intensity. This investigation will be significant in exploring the toxicity profile of SNs for their in vivo.

Insights into the binding mechanism of two-dimensional black phosphorus nanosheets-protein associations.

Exploring the protein-nanomaterials interactions is the topic of high relevance for the future applications of new nanomaterials in biological system. Herein, the binding mechanism of bovine serum albumin(BSA) and bovine hemoglobin(BHB) with two-dimensional black phosphorus nanosheets (BP NSs) was reported. Muti-spectral results showed that the combination of BP NPs with protein resulted in the fluorescence quenching of BSA and BHB and induced the extension of the protein peptide chain by van der Waals forces, hydrophobic forces, and electron-transfer forces. Both BSA and BHB retain their structure in α-helix form. The induced circular dichroism (ICD) spectral results showed that the presence of BP NPs partly destroyed the binding domain of BHB with bilirubin and altered the tertiary structure of BHB by BP NPs binding.

Selective separation of bovine hemoglobin using magnetic mesoporous rare-earth silicate microspheres

Selective separation of heme proteins and peptides from complicated biological samples before comprehensive identification and characterization of intact biomolecules which are low stoichiometry is indispensable for ongoing proteomics. Here, three magnetic mesoporous rare-earth silicate (rare-earth = Er, Tm, Yb) microspheres prepared by facile solvothermal method were used as novel adsorbents for the selective isolation of bovine hemoglobin (BHb), and magnetic mesoporous ytterbium silicate showed apparent adsorption efficiency in isolating BHb with a adsorption capacity of 304.4 mg/g after the comparison. The retained BHb could be eluted by using Na2CO3 as stripping reagent. Meanwhile, Circular dichroism spectra illustrated that the microspheres posed no effect on the secondary structure of BHb. The resultant magnetic particles were characterized by transmission electron microscope, scanning electron microscope, x-ray powder diffraction, vibrating sample magnetometer, Fourier transform infrared spectroscopy, N2 adsorption−desorption isotherm and zeta potential. The as-prepared magnetic microspheres showed high specificity for the separation of BHb from bovine plasma as corroborated by SDS-PAGE and MALDI-TOF MS analysis, which would be expected to possess potential application in isolation of other heme proteins in complex biological samples.

Binding interactions of MoS2 quantum dots with hemoglobin and their adsorption isotherms and kinetics in vitro

To elucidate the binding interaction and adsorption isotherms and kinetics of molybdenum disulfides quantum dots (MoS2 QDs) with bovine hemoglobin (BHB) in vitro, it is urgent to investigate their binding mechanism in this work. The experimental results indicated that MoS2 QDs partly induced denaturation and expansion of secondary structure of BHB and the microenvironment changes of heme by the ground state complex formation of BHB with MoS2 QDs. The tertiary structure and the thermal denaturation of BHB on MoS2 QDs surface are not obviously different from only BHB solution. The experimental results were verified correctness with molecular modeling analysis. The Soret band changes indicated that the presence of MoS2 QDs partly protects the oxidation process of BHB by H2O2. In addition, the kinetics of BHB adsorption onto MoS2 QDs follows the pseudo-second-order kinetic model with high adsorption capacity, their adsorption was a fast process. This in vitro study could act as a precedent in understanding the interaction mechanism of biomolecules with MoS2-based nanomaterials.

A biophysical probe on the binding of 2-mercaptothioazoline to bovine hemoglobin.

2-Mercaptothiazoline (MTZ) is broadly present in daily use as an antifungal reagent, a brightening agent, and a corrosion inhibitor. MTZ is potentially harmful for human health. Although the toxic effects of MTZ on experimental animals have been reported, the effects of MTZ on the proteins in the circulatory system at the molecular level have not been identified previously. Here, we explored the interaction of MTZ with bovine hemoglobin (BHb) in vitro using multiple spectroscopic techniques and molecular docking. In this study, the binding capacity, acting force, binding sites, molecular docking simulation, and conformational changes were investigated. MTZ quenched the intrinsic emission of BHb via the static quenching process and could spontaneously bind with BHb mainly through van der Waals forces and hydrogen bond. The computational docking visualized that MTZ bound to the β2 subunit of BHb, which further led to some changes of the skeleton and secondary structure of BHb. This research provides valuable information about the molecular mechanisms on BHb induced by MTZ and is beneficial for clarifying the toxicological actions of MTZ in blood.

Effects of N-acetyl-L-cysteine-capped CdTe quantum dots on bovine serum albumin and bovine hemoglobin: isothermal titration calorimetry and spectroscopic investigations.

The interactions of N-acetyl-L-cysteine-capped CdTe quantum dots (QDs) with bovine serum albumin (BSA) and bovine hemoglobin (BHb) were investigated by isothermal titration calorimetry (ITC), fluorescence, synchronous fluorescence, fluorescence lifetime, ultraviolet-visible absorption, and circular dichroism techniques. Fluorescence data of BSA-QDs and BHb-QDs revealed that the quenching was static in every system. While CdTe QDs changed the microenvironment of tryptophan in BHb, the microenvironment of BSA kept unchanged. Adding CdTe QDs affected the skeleton and secondary structure of the protein (BSA and BHb). The ITC results indicated that the interaction between the protein (BSA and BHb) and QDs-612 was spontaneous and the predominant force was hydrophobic interaction. In addition, the binding constants were determined to be 1.19 × 10(5) L mol(-1) (BSA-QDs) and 2.19 × 10(5) L mol(-1) (BHb-QDs) at 298 K. From these results, we conclude that CdTe QDs have a larger impact on the structure of BHb than BSA.

Interaction of Bisphenol A with Bovine Hemoglobin Using Spectroscopic and Molecular Modeling Methods

The interaction of bisphenol A with bovine hemoglobin (BHb) under physiological conditions was investigated by using fluorescence, ultraviolet-visible (UV-Vis) absorption, circular dichroism (CD), and molecular modeling. The experimental results showed that BPA can bind with BHb to form a complex. The binding constant Ka and the number of binding sites n were calculated to be 1.49 × 10(5) L mol(-1) and 1, respectively. Molecular modeling study revealed that BPA bound into BHb central cavity, and the binding mode of BPA-BHb complex could be hydrogen bonding. The UV-Vis absorption and CD spectra indicated that the secondary structure of BHb was altered, which may affect physiological functions of hemoglobin. This work is helpful for clarifying the molecular toxic mechanism of BPA in vivo.

Fragmentomics of proteins and natural oligopeptides

The substantiation and definition of the term "fragmentomics" are given. Within the framework of this scientific direction, a theoretical structural and functional analysis of all possible fragments of one protein molecule was performed to determine the sites that could be potential sources of the regulatory oligopeptides. For this purpose, the data on the primary structure of bovine hemoglobin, the information of the database EROP-Moscow on the structure and functions of natural oligopeptides, and a special computer program complex were used. As a result, natural nonhemoglobin oligopeptides containing hemoglobin fragments and natural oligopeptides representing the exact structures of hemoglobin fragments were found. Most abundant among them are neuropeptides, antimicrobial oligopeptides, and hormones. It has been shown that bovine tetrapeptide fragments identified in nonhemoglobin oligopeptides possessing the given functions occur in the amino acid sequences of experimentally obtained hemoglobin oligopeptides having the same functions. The method described has allowed one to reveal also potentially active sites of hemoglobin amino acid sequence not yet investigated experimentally. The possibility of the natural formation of regulatory oligopeptides from hemoglobin molecules and other food proteins, the formation of an exogenous oligopeptide pool in the gastrointestinal tract, and the conformity of the results to the ideas about the natural continuum of regulatory oligopeptides is considered.

Encapsulation of hemoglobin in a bicontinuous cubic phase lipid

The effects of encapsulating bovine hemoglobin (BHb) in the bicontinuous cubic phase formed by monooleoylglycerol and water was investigated with Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction. Cubic phase was formed in the presence of 1–10 wt% BHb. Studies using X-ray diffraction reveal that at 0.5–2.5 wt% BHb, the cubic phase structure is characterized by the double diamond lattice ( Pn3m). At 2.5–5 wt% BHb, coexistence of two cubic phase structures, Pn3m and the gyroid lattice ( la3d), was observed while at BHb concentrations higher than 5 wt% the gyroid structure persists. FTIR shows there is an increase in intensity of the free νC = O (1745 cm −1) and a corresponding decrease in the intensity of the hydrogen bonded νC = O (1720 cm −1) cs the BHb concentration is increased. The νC-O-CO peak shifts from 1183 cm −1 to 1181 cm −1 as the concentration of BHb is raised from 2.5 to 10 wt% indicating BHb may induce subtle changes in the interfacial region of cubic phase monoolein. The bandwidth of the ν asCH 2 stretch (2926 cm −1) increased in the presence of 5 wt% BHb compared to samples with 2.5 or 10 wt% BHb. The increase in frequency of the ν sCH 2 stretch (2854 cm −1) induced by increasing temperature 20 to 60°C was dampened when BHb was present compared to samples heated in isotonic buffer. Analysis of the amide I band at 1650 cm −1 showed that the secondary structure of BHb is not affected by encapsulation in monoolein. In vitro release studies showed that 45% of the entrapped BHb was released after 144 h at 37°C. The porous nature of bulk cubic phase was further demonstrated by diffusion of K 2Fe(CN) 6 and conversion of 73% of the oxyhemoglobin to methemoglobin after 1 h. These results suggest that the cubic phase may be useful for encapsulation of Hb as a red cell substitute and for the encapsulation and delivery of other bioactive agents.