Interaction Of Hb Research Articles

Oleic acid prevents erythrocyte death by preserving haemoglobin and erythrocyte membrane proteins.

Haemolysis of erythrocytes upon exposure to haemato-toxic phenylhydrazine (PHZ), makes it an experimental model of anaemia and a partial model of β-thalassaemia, where oxidative stress (OS) was identified as principal causative factor. Oleic acid (OA) was evidenced to ameliorate such stress with antioxidative potential. Erythrocytes were incubated in vitro using 1mM PHZ, 0.06nM OA. Erythrocyte membrane protein densities and haemoglobin (Hb) status were examined. Any interaction of Hb with PHZ/OA was checked by calorimetric and spectroscopic analysis using pure molecules. Occurrence of erythrocyte apoptosis and involvement of free iron in all groups were evaluated. PHZ exposure to erythrocytes results in OS with subsequent apoptosis as evidenced from increased lipid peroxidation and translocation of phosphatidylserine in outer membrane. Preservations of erythrocyte cytoskeletal architecture and membrane bound enzyme activity were found in presence of OA. Moreover, both heme and globin of Hb was examined to be conserved by OA. Presence of OA, impeded apoptosis also, possibly by thwarting Hb breakdown followed by free iron release and consequent free radical generation. Additionally, direct sequential binding of OA with PHZ endorsed another protective mechanism of OA toward erythrocytes. OA affords protection to erythrocytes by conserving its major components and prevents haemolysis which project OA as a haemato-protective agent. Apart from combating PHZ toxicity, anti-apoptotic action of OA strongly suggests its usage in anaemia and β-thalassaemia patients to curb irreversible erythrocyte breakdown. This research strongly recommends OA in pure form or from dietary sources as a therapeutic against haemolytic disorders.

Overview on hydrogen sulfide-mediated suppression of vascular calcification and hemoglobin/heme-mediated vascular damage in atherosclerosis

Vulnerable atherosclerotic plaques with hemorrhage considerably contribute to cardiovascular morbidity and mortality. Calcification is the main characteristic of advanced atherosclerotic lesions and calcified aortic valve disease (CAVD). Lyses of red blood cells and hemoglobin (Hb) release occur in human hemorrhagic complicated lesions. During the interaction of cell-free Hb with plaque constituents, Hb is oxidized to ferric and ferryl states accompanied by oxidative changes of the globin moieties and heme release. Accumulation of both ferryl-Hb and metHb has been observed in atherosclerotic plaques. The oxidation hotspots in the globin chain are the cysteine and tyrosine amino acids associated with the generation of Hb dimers, tetramers and polymers. Moreover, fragmentation of Hb occurs leading to the formation of globin-derived peptides. A series of these pro-atherogenic cellular responses can be suppressed by hydrogen sulfide (H2S). Since H2S has been explored to exhibit a wide range of physiologic functions to maintain vascular homeostasis, it is not surprising that H2S may play beneficial effects in the progression of atherosclerosis. In the present review, we summarize the findings about the effects of H2S on atherosclerosis and CAVD with a special emphasis on the oxidation of Hb/heme in atherosclerotic plaque development and vascular calcification.

Carbon dots and Methylene blue facilitated photometric quantification of Hemoglobin

Early detection and monitoring of any abnormality of Hemoglobin (Hb) concentration in whole blood samples are important as this may be related to anemia, leukemia, dengue, etc. To facilitate quantitative detection and to monitor the hemoglobin level in the blood, we attempt to develop a low-cost, portable point of care (POC) device based on the spectrophotometric principle. Optical sensitivities of carbon quantum dots (CDs) are found to be highly responsive, while there is a selective reaction between Hb and reduced form of Methylene Blue (MBred). The interaction of Hb, MBred, and CDs is delineated using UV–Visible (UV–Vis) spectroscopy. CDs have a characteristic UV–Vis peak at ∼ 347 nm, and it shows a gradual increase in intensity with a slight red shift (∼355 nm) on the progressive increase in Hb concentration. Simultaneously, the colorless MBred is oxidized to its blue oxidized form MBox and its characteristic peak starts reappearing at ∼ 663 nm. These responses are exploited to quantify Hb concentration with a limit of detection (LOD) as low as ∼ 2 g dL–1 in a developed POC device, and the results are validated with the clinical data obtained from a local hospital with reasonably good agreement. This photometric detection approach can be adopted for other quantitative biosensors.

Spectroscopic investigation on molecular aspects and structural and functional effects of tetraethyl pyrophosphate organophosphorus insecticide interaction with adult human hemoglobin

Organophosphates are extremely toxic compounds that use extensively in agriculture and household as insecticides. However, their binding mechanism to bio-macromolecules especially blood proteins is not clearly understood. In this research, various spectroscopic techniques utilized to analyze the effect of Tetraethyl Pyrophosphate (TEPP), as an organophosphorus insecticide, on the structure, function, stability, and aggregation of adult human hemoglobin and also hemolysis potential of the TEPP on red blood cells (RBCs) examined. Molecular docking was used for TEPP binding to human Hemoglobin (Hb), too. The results demonstrated that the TEPP insecticide has the potential for lysing RBCs. UV-Vis experiment indicated that globin part and heme group influenced by TEPP. Oxygen affinity measurements revealed the formation of deoxy-Hb and met-Hb, also decreased in oxygen affinity of Hb upon interaction with TEPP that is due to heme destruction. Fluorescence spectroscopy confirmed the production of heme degradation species after interaction of Hb with TEPP, which is inconsistent with oxygen affinity measurements. Thermal and aggregation studies indicated that TEPP induced aggregation of Hb in a concentration manner and Tm of protein reduced to lower temperatures. Docking's study also showed that TEPP interacts with Hb through hydrophobic interactions, which confirms UV-Vis results. ATR-FTIR study also revealed that TEPP can induce changes in the alpha helix element of Hb’s secondary structure. Totally, Experimental and theoretical results indicate that tetraethyl pyrophosphate has unfavorable effects on hemoglobin structure and function. Communicated by Ramaswamy H. Sarma

Spectroscopic Study of Interaction of Bare, Citrate Capped and BSA Capped Fe3O4 Nanoparticles with Hemoglobin

Background:Fe3O4nanoparticles have great potential in different biomedical applications. The study of the interaction of bare, and capped Fe3O4nanoparticles with common blood proteins is a field of interest for understanding the underlying mechanism and biocompatibility.Objective:This work aims at studying the nature of binding of bare, citrate functionalised and bovine serum albumin coated Fe3O4nanoparticles (Fe3O4NPs, CFe3O4NPs and BFe3O4NPs) with human hemoglobin (Hb), and their instantaneous effect on amino acid group, heme group and secondary structure of Hb.Methods:Nanoparticles were prepared by the chemical route and characterised by TEM, XRD and UV-Visible and FTIR spectroscopy. UV-visible absorbance and fluorescence emission/ excitation spectroscopy and circular dichroism were performed to study the interaction of nanoparticles with Hb.Results:UV-visible absorbance spectroscopy showed no blue or red shift of absorption peaks. Benesi-Hildebrand curves for the amino acid band and soret band of Hb absorbance spectrum were straight lines with positive intercepts; apparent binding constants and Gibbs free energy change were within a moderate level; they were larger for amino acid band in the presence of CFe3O4NPs, and for soret band in the presence of Fe3O4NPs, but noticeably small for both bands in the presence of BFe3O4NPs. Fluorescence emission/excitation spectra showed no noticeable shift of emission/excitation peak position of Hb in the presence of the three nanoparticles. Multiple peak fitting, done for the L-peak of the excitation spectrum of Hb, showed a major increase in the percentage of peak area of Tyr in the presence of CFe3O4NPs. Circular dichroism measurement showed that CFe3O4NPs, Fe3O4NPs and BFe3O4NPs reduced the α-helix content of Hb in decreasing order.Conclusion:Ground state complex formation of human hemoglobin with the studied nanoparticles with 1:1 stoichiometric ratio is suggested. Moreover, it has been observed that CFe3O4NPs may have a stronger interaction with the amino acid group while bare Fe3O4NPs may have a stronger interaction with the heme group of Hb. Hinderance of the energy transfer from tyrosine to tryptophan of Hb in the presence of CFe3O4NPs is also suggested. CFe3O4NPs may also have some effect on the secondary structure of Hb as indicated through reduction of the α-helix content. BFe3O4NPs have shown very weak interaction with Hb in the UV-visible absorbance spectroscopy, fluorescence emission/excitation spectroscopy and circular dichroism experiment.

The Interaction of Hemoglobin With Sodium Dodecyl Sulfate in Presence of Ascorbic Acid

Background: Hemoglobin (Hb), oxygen, carbon dioxide, and electron transporter of the body, may enter to an oxidation process that can convert oxyhemoglobin (oxyHb) to methemoglobin (metHb) and hemichrome. Surfactants can facilitate oxidation process that may accumulate hemichrome in red blood cells. Methods: In the present study, the interaction of purified Hb with sodium dodecyl sulfate (SDS, 0-5 mM) and ascorbic acid (AA, 0-5 mM) was evaluated by UV-Vis spectroscopy and multivariate curve resolution techniques. Results: Reconstructed spectral and concentration profiles showed three forms of Hb name as oxyHb, metHb, and hemichrome with lack of fit values less than 1.85%. AA hindered the oxidation process of Hb. Conclusion: A decrease in critical micelle concentration of SDS in the presence of AA and interaction of AA with hydrogen peroxide, which is produced during the interaction of Hb with SDS, are two reasons for diminution in the oxidation process of Hb when accompanied with AA.

Comparison of nitric oxide levels in patients undergoing surgery in absence and deliverance of blood transfusion in association with hemoglobin

Blood transfusion has an important role in patients undergoing surgery. However, besides providing sufficient amounts of oxygen, blood transfusion should protect the safety of blood recipients too. Hemoglobin (Hb) is the most abundant intra-erythrocytic protein and reacts rapidly with nitic oxide (NO), the endothelium-derived relaxing factor that maintains blood flow and oxygen transport to tissues. The interaction of NO and Hb have been found to have unavoidable consequences. Clinical factors play an important role in the decision of transfusion if otherwise avoidable. Keywords: Blood transfusion, Nitric oxide, Hemoglobin.

Structural analysis of the interaction between free, glycated and fructated hemoglobin with propolis nanoparticles: A spectroscopic study

Non enzymatic Glycation is the main causes of diabetic complications. Propolis is a natural product of different plant exudates and buds which has different biological properties such as anti-hyperglycemia. In attention to better performance of nanoparticles in treatment, we synthesized propolis nanoparticles (PNP) and analyzed their physicochemical properties by dynamic light scattering (DLS), scanning electron microscopy (SEM), Zeta potential and FTIR analyses. Then, the structural changes of human hemoglobin (Hb), in three different forms of free, glycated and fructated Hb upon interaction with PNP at two temperatures of 25 and 37°C were investigated using fluorescence and far-UV circular dichoroism (CD) spectroscopic techniques. The size distribution of PNP was less than 100nm. Fluorescence results indicated that PNP have a strong ability in quenching the intrinsic fluorescence of different forms of Hb. The binding constants, number of binding sites and thermodynamic parameters of these interactions were calculated and compare to each other. The Gibbs free energy values for glycated and fructated Hb with PNP were calculated-1635 and 1065J/mol, respectively at 25°C which indicates that interaction of Hb with PNP is more favorable than interaction of GHb with PNP. CD spectra indicated that PNP lead to no significant changes in the secondary structure of different types of Hb. So, PNP as a natural product, due to antioxidant properties and lack of toxicity, can be used in the drug delivery system.

Human hemoglobin adsorption onto colloidal cerium oxide nanoparticles: a new model based on zeta potential and spectroscopy measurements

The nanoparticle (NP)-induced conformational changes of protein and NP agglomeration have gained a remarkable interest in medical and biotechnological fields. Herein, the effect of human hemoglobin (Hb) on the colloidal stability of cerium oxide NP (CNP) was investigated by dynamic light scattering (DLS), zeta potential, and TEM analysis. In addition, the effect of CNP on the heme degradation and structural changes of Hb was studied using fluorescence, circular dichroism (CD), and UV–visible (UV–vis) spectroscopic methods. DLS and TEM analysis showed that the presence of Hb can increase the mean diameter of CNP. Zeta potential measurements revealed that CNP demonstrated a higher charge distribution relative to CNP/Hb complex. Besides, fluorescence studies indicated that two fluorescent heme degradation products are revealed during the interaction of CNP with Hb. Near UV-CD spectroscopy also showed that the microenvironmental changes of heme groups occur after interaction of Hb with CNP. The result of thermal behavior of Hb confirmed the structural changes of protein, which referred to decrease in the Hb stability in the presence of CNP. Indeed, the finding related to structural and functional changes of Hb induced by CNP may be crucial to obtain information regarding the side effects of NPs. Finally, this data reveal much insight into the effects of the interaction on protein structural changes and NP agglomeration, and can correlate the zeta potential of NP-protein complexes with the nature of the principle NP-protein interaction.

Studying the interaction between three synthesized heterocyclic sulfonamide compounds with hemoglobin by spectroscopy and molecular modeling techniques

The interaction between synthesized heterocyclic benzene sulfonamide compounds, N-(7-benzyl-56-biphenyl-2m-tolyl-7H-pyrrolo[23-d]pyrimidine–4–yl)-benzene sulfonamide (HBS1), N-(7-benzyl-56-biphenyl-2-m-tolyl-7H-pyrrolo[23-d] pyrimidine-4-yl)-4-methyl- benzene sulfonamide (HBS2), and N-(7-benzyl-56-biphenyl-2-m-tolyl-7H-pyrrolo[23-d]pyrimidine-4-yl)-4-chloro-benzene sulfonamide (HBS3) with Hb was studied by fluorescence quenching, zeta potentional, circular dichroism, and molecular modeling techniques. The fluorescence spectroscopy experiments were performed in order to study the conformational changes, possibly due to a discrete reorganization of Trp residues during binding between HBS derivatives and Hb. The variation of the KSV value suggested that hydrophobic and electrostatic interactions were the predominant intermolecular forces stabilizing the complex. The KSV1 ans KSV2 values of HBS derivatives with Hb are .6 × 1013 and 3 × 1013 M−1 for Hb–HBS1, 1 × 1013 and 4 × 1013 M−1 for Hb–HBS2, .9 × 1013, and 6 × 1013 M−1 for Hb–HBS3, respectively. The molecular distances between Hb and HBS derivatives in binary and ternary systems were estimated according to Förster’s theory of dipole–dipole non-radiation energy transfer. The quantitative analysis data of circular dichroism spectra demonstrated that the binding of the three HBS derivatives to Hb induced conformational changes in Hb. Changes in the zeta potential of the Hb–HBS derivatives complexes demonstrated a hydrophobic adsorption of the anionic ligand onto the surface of Hb as well as both electrostatic and hydrophobic adsorption in the case of the complex. The modeling data thus confirmed the experimental results. This study is expected to provide important insight into the interaction of Hb with three HBS derivatives to use in various toxicological and therapeutic processes.

Studies on the interaction between nanodiamond and human hemoglobin by surface tension measurement and spectroscopy methods

In this study, a novel method to probe molecular interactions and binding of human hemoglobin (Hb) with nanodiamond (ND) was introduced based on the surface tension measurement. This method complements conventional techniques, which are basically done by zeta potential and dynamic light scattering (DLS) measurements, near and far circular dichroism (CD) spectroscopy, intrinsic and extrinsic fluorescence spectroscopy. Addition of ND to Hb solution increased the surface tension value of Hb–ND complex relative to those of Hb and ND molecules. The zeta potential values reveled that Hb and ND provide identical charge distribution at pH 7.5. DLS measurements demonstrated that Hb, ND, and ND–Hb complex have hydrodynamic radiuses of 98.37 ± 4.57, 122.07 ± 7.88 nm and 62.27 ± 3.70 at pH of 7.5 respectively. Far and near UV-CD results indicated the loss of α-helix structure and conformational changes of Hb, respectively. Intrinsic fluorescence data demonstrated that the fluorescence quenching of Hb by ND was the result of the static quenching. The hydrophobic interaction plays a pivotal role in the interaction of ND with Hb. Fluorescence intensity changes over time revealed conformational change of Hb continues after the mixing of the components (Hb–ND) till 15 min, which is indicative of the denaturation of the Hb relative to the protein control. Extrinsic fluorescence data showed a considerable enhancement of the ANS fluorescence intensity of Hb–ND system relative to the Hb till 60 nM of ND, likely persuaded by greater exposure of nonpolar residues of Hb hydrophobic pocket. The remarkable decrease in Tm value of Hb in Hb–ND complex exhibits interaction of Hb with ND conducts to conformational changes of Hb. This study offers consequential discrimination into the interaction of ND with proteins, which may be of significance for further appeal of these nanoparticles in biotechnology prosecution.

Impact of Surface Functionalization of AgNPs on Binding and Conformational Change of Hemoglobin (Hb) and Hemolytic Behavior

With increasing application of silver nanoparticles (AgNPs) in biological sensing, detection, enzyme immunoassays, and antimicrobial activity as well as SERS, it has been realized that the toxicity limits their application in biomedicine. However, the interaction of proteins with nanoparticle (NPs) surface possessing different chemical functionalities reduces the potential impact of NPs rendering them biocompatible. Here, we have functionalized the AgNPs with β-hydroxy propyl cyclodextrin (β-HPCD-AgNPs) and studied the conformational changes and thermal stability of hemoglobin (Hb) upon interaction with β-HPCD-AgNPs. Interaction of Hb with borohydride-capped AgNPs (BH4-AgNPs) was also evaluated. Hb remained in native form upon binding with β-HPCD-AgNPs which is unveiled by UV–vis and fluorescence spectroscopic as well as dynamic light scattering (DLS) studies. However, BH4-AgNPs induced unfolding of Hb and reduced the α-helical content following interaction with Hb. Further, the accessibility of tryptopha...

Genetic heterogeneity of hemoglobin AEBart's disease: A large cohort data from a single referral center in northeast Thailand

AEBart's disease is a thalassemia intermedia usually characterized by the interaction of α(0)-thalassemia with either deletional or non-deletional α(+)-thalassemia in Hb E heterozygote. Genotypic and phenotypic features are heterogeneous. We studied the hematologic and molecular characteristics of this disease in a cohort of 173 Thai patients encountered at our center in northeast Thailand. Hemoglobin and DNA analyses identified patients with deletional AEBart's disease (n=84), Hb Constant Spring AEBart's disease (n=81), Hb Paksé-AEBart's disease (n=5), AEBart's disease with codon 30 mutation (n=1) and two hitherto un-described forms of AEBart's disease due to interaction of Hb E heterozygote and α(0)-thalassemia with the -α(16.6)kb deletional α(+)-thalassemia (n=1) and Hb Q-Thailand (n=1). Different phenotypic expression of these AEBart's diseases with low Hb, Hct and MCV and increased RDW values with marked reduction in Hb E levels were observed. It was found that all these forms of AEBart's disease showed similar thalassemia intermedia phenotypes but those with non-deletional forms were relatively more anemic. Our data confirm that in such area with high prevalence of hemoglobinopathies such as Southeast Asia, identification of rare thalassemia alleles in a thalassemia intermedia patient should not be ignored. Careful consideration of different phenotypic expression may help in providing presumptive diagnosis of this disease where access to molecular testing is limited. However, molecular diagnostic is useful for predicting the clinical outcome and improving genetic counseling of these complex hemoglobinopathies.

Direct electrochemistry and electrocatalysis of hemoglobin immobilized on biocompatible poly(styrene-alternative-maleic acid)/functionalized multi-wall carbon nanotubes blends

In this study, we investigate the direct electron-transfer reactivity of immobilized hemoglobin (Hb) on a biocompatible poly(styrene-alternative-maleic acid) (PSMAC) copolymer/multi-walled carbon nanotubes (MWCNTs) blend for biosensor designs. The copolymer possesses good biocompatibility, uniformity, conformability and is ready for protein immobilization. On the other hand, electrochemical measurements show that the presence of MWCNTs provides a unique structure for interaction of Hb and copolymer and facilitate the direct electron transfer between the immobilized Hb and the surface conductivity. The immobilized Hb maintains its bioactivities and displays an excellent electrochemical behavior. The proposed method opens a way to develop biosensors by using nanostructured materials mixed with low electrical conductivity matrixes. The biosensor was used to catalyze the reduction of hydrogen peroxide. The electrocatalytic response showed a linear dependence on the H2O2 concentration ranging widely from 1.0 to 56.0μM with a detection limit of 0.38μM at 3σ.

Theoretical studies of intermolecular interactions of arachno-pentaborane (11) with HF and LiH

Ab initio calculations were used to analyze the interactions of arachno-B5H11 with HF and LiH at the MP2/6-311++g(d,p) computational level. The B5H11 interact with HF and LiH through both its terminal and bridged hydrogens. Interaction of Hb with HF and LiH result to Hb…F hydrogen and Hb…H dihydrogen bonds, respectively. In contrast, Ht…H and Ht…Li bonds were obtained from interactions of Ht of B5H11 with HF and LiH. In the two complexes named as S4 and S6 the B5H11 shows interesting ability for trapping the HF and LiH molecules in host–guest like interactions. The structures obtained have been analyzed using AIM methodology.

Hemoglobin Redox Reactions and Red Blood Cell Aging

The physiological mechanism(s) for recognition and removal of red blood cells (RBCs) from circulation after 120 days of its lifespan is not fully understood. Many of the processes thought to be associated with the removal of RBCs involve oxidative stress. We have focused on hemoglobin (Hb) redox reactions, which is the major source of RBC oxidative stress. The importance of Hb redox reactions have been shown to originate in large parts from the continuous slow autoxidation of Hb producing superoxide and its dramatic increase under hypoxic conditions. In addition, oxidative stress has been shown to be associated with redox reactions that originate from Hb reactions with nitrite and nitric oxide (NO) and the resultant formation of highly toxic peroxynitrite when NO reacts with superoxide released during Hb autoxidation. The interaction of Hb, particularly under hypoxic conditions with band 3 of the RBC membrane is critical for the generating the RBC membrane changes that trigger the removal of cells from circulation. These changes include exposure of antigenic sites, increased calcium leakage into the RBC, and the resultant leakage of potassium out of the RBC causing cell shrinkage and impaired deformability. The need to understand the oxidative damage to specific membrane proteins that result from redox reactions occurring when Hb is bound to the membrane. Proteomic studies that can pinpoint the specific proteins damaged under different conditions will help elucidate the cellular aging processes that result in cells being removed from circulation.

Propylbenzmethylation at Val-1(α) markedly increases the tetramer stability of the PEGylated hemoglobin: A comparison with propylation at Val-1(α)

BackgroundHemoglobin (Hb)-based oxygen carriers (HBOCs) are potential pharmaceutical agents that can be used in surgery or emergency medicine. PEGylation can modulate the vasoactivity of Hb and is a widely used approach to develop HBOCs. However, PEGylation can significantly enhance the tetramer–dimer dissociation of Hb, which may perturb the structure of Hb and increase its observed adverse effect. Thus, it is necessary to increase the tetramer stability of the PEGylated Hb. MethodsPropylbenzmethylation at Val-1(α) of HbA was carried out to stabilize the Hb tetramer. The propylbenzmethylated Hb at Val-1(α) (PrB-Hb) was used as the starting material for site-specific PEGylation at Cys-93(β) of Hb using maleimide PEG. Structural and functional properties, autoxidation rate and thermal stability of the resultant product (PEG-PrB-Hb) were measured. ResultsPropylbenzmethylation at Val-1(α) led to 25-fold and 24-fold decreases in the tetramer–dimer dissociation constant of HbA and PEG-Hb, respectively. The increased tetramer stability is due to the enhanced hydrophobicity of the area around Val-1(α) and the increased polar interaction of Hb upon propylbenzmethylation. Thus, the structural and functional properties of PEG-Hb were improved, and its autoxidation rate and thermal denaturation were decreased. ConclusionPropylbenzmethylation at Val-1(α) showed higher ability than propylation at Val-1(α) to improve the structural and functional properties and decrease the side effect of PEG-Hb. General significanceOur study can facilitate the biotechnological development of stable PEGylated Hb as more advanced HBOC. Our study is also expected to improve the stability of the tetrameric or dimeric proteins (e.g., uric oxidase) by propylbenzmethylation at their N-terminus.

Theoretical study of hydrogen and dihydrogen bond interaction of B6H10 with the HF molecule

Ab initio calculations were used to analyze the interactions of B6H10 with an HF molecule at the MP2/6-311++g(d,p) and B3LYP/6-311++g(d,p) computational levels. B6H10 could interact with HF through both its terminal (Ht) and bridged (Hb) hydrogens. The interaction of Ht and Hb of B6H10 with HF could result in the formation of Ht···H and Hb···F dihydrogen and hydrogen bond complexes, respectively. The obtained structures have been analyzed with the Atoms in Molecules methodology.

Gold nanoparticle induced conformational changes in heme protein

Change of a-helical structure of heme protein (Hb) to a b-sheet and random coil conforma- tion because of the interaction of glycine capped gold nanoparticles (20-60 nm) as observed from attenua- tion total reflectance, absorption, Fourier transform infra red, and Circular Dichroism spectroscopy has been reported in this article. Upon interaction, protein takes a cylindrical shape of length 12 lm and diameter 0.35 lm as revealed from scanning electron micros- copy and transmission electron microscopy. The Selected-Area Electron beam Diffraction pattern shows change of crystalline structure in GNP to amorphous nature with the interaction of Hb.

The air we breathe: three vital respiratory gases and the red blood cell: oxygen, nitric oxide, and carbon dioxide

Three vital respiratory gases-oxygen (O(2)), nitric oxide (NO), and carbon dioxide (CO(2))-intersect at the level of the human red blood cell (RBC). In addition to hemoglobin (Hb)'s central role in O(2) transport, interaction of Hb with the Band 3 metabolon balances RBC energy flow. 2,3-Diphosphoglycerate enhances O(2) transport across the placenta and plays an important role in regulating RBC plasticity. NO is a key mediator of hypoxic vasodilation, but the precise role of RBC Hb remains controversial. In addition to established theories that depend on RBC uptake, delivery, and discharge of NO or its metabolites, an alternative hypothesis based on RBC permeability is suggested. NO depletion by free Hb may account for several clinical features seen during intravascular hemolysis or during deliberate infusion of Hb solutions used as RBC substitutes. CO(2) released by tissues triggers oxygen release through a series of well-coordinated reactions centered on the Band 3 metabolon. While RBC carbonic anhydrase and the Band 3 anion exchanger are central to this process, there is surprisingly little research on the kinetics of CO(2) clearance by transfusion. The three RBC gases are directly related to the three principal gases of Earth's atmosphere. Human fossil fuel consumption dumps 90 million metric tons of carbon into the atmosphere annually. Increasing CO(2) levels are linked to global warming, melting Arctic ice, rising sea levels, and climate instability. Just as individual cells depend on balance of the three vital gases, so too will their balance determine survival of life on Earth.