Showing papers on "Myoglobin published in 2020"
TL;DR: This review examines how metabolites and mitochondrial activity can influence myoglobin oxygenation and metmyoglobin reducing activity and highlights recent research that has examined myoglobin redox dynamics, sarcoplasmic metabolite changes, and/or postmortem biochemistry.
Abstract: Appearance is an important sensory property that significantly influences consumers' perceptions of fresh meat quality. Failure to meet consumer expectations can lead to rejection of meat products, concomitant loss in value, and potential production of organic waste. Immediately after animal harvest, skeletal muscle metabolism changes from aerobic to anaerobic. However, anoxic post-mortem muscle is biochemically active, and biomolecular interaction between myoglobin, mitochondria, metabolites, and lipid oxidation determines meat color. This review examines how metabolites and mitochondrial activity can influence myoglobin oxygenation and metmyoglobin reducing activity. Further, the review highlights recent research that has examined myoglobin redox dynamics, sarcoplasmic metabolite changes, and/or post-mortem biochemistry.
69 citations
TL;DR: In this article, the authors used spectroscopic and simulation approaches to study the alterations of the myoglobin structure and stability in glycerol presence, and they showed a stability improvement of the complex myoglobin-glycerol.
29 citations
TL;DR: It is indicated that myoglobin was efficiently removed with CytoSorb® following exchange with the conventional high cut-off filter in continuous venovenous haemodialysis in severe traumatic rhabdomyolysis.
Abstract: Rhabdomyolysis, if severe, can lead to acute kidney injury (AKI). Myoglobin is an iron and oxygen-binding protein that is freely filtered by the glomerulus. Precipitation of myoglobin in the nephrons' distal parts is responsible for tubular damage with AKI as a consequence. Extracorporeal clearance of myoglobin is conventionally attempted by the use of continuous renal replacement therapy (CRRT) with high cut-off dialysis membranes to limit the extent of the damage. We describe a case of a 56-year-old man with traumatic crush injury and a persistent source of muscle ischaemia unresponsive to high dose CRRT with EMiC-2 filter. Due to therapy failure, he was subsequently treated with the addition of a haemoadsorber (CytoSorb®) to the circuit. This reduced myoglobin and creatine kinase levels successfully despite ongoing tissue ischaemia. However, CytoSorb® was not enough to maintain microcirculatory perfusion, resulting in the eventual demise of the patient due to severity of the injury. Our report indicates that myoglobin was efficiently removed with CytoSorb® following exchange with the conventional high cut-off filter in continuous venovenous haemodialysis in severe traumatic rhabdomyolysis.
24 citations
TL;DR: It is concluded that CORM-401 produced most reliable CO-specific results for the modulation of typical CO targets in biological test systems and address susceptible heme proteins.
24 citations
TL;DR: Overall, magnetic field promoted exposed active groups as the preferred oxidation target, thus decreasing the oxidation rate of central iron atoms and promoting Mb stability by redistributing particle size and increasing zeta potential.
21 citations
23 Mar 2020
TL;DR: Observing the effects of macromolecular crowding on its stability by chemical-induced denaturation of the protein showed that the degree of destabilization of myoglobin was greater due to ficoll 70 as compared to that of dextran 70 so it can be understood that the nature of the crowder or the shape of the Crowder has an important role towards the stability of proteins.
Abstract: Generally, in vivo function and structural changes are studied by probing proteins in a dilute solution under in vitro conditions, which is believed to be mimicking proteins in intracellular milieu. Earlier, thermal-induced denaturation of myoglobin, in the milieu of crowder molecule showed destabilization of the metal protein. Destabilization of protein by thermal-induced denaturation involves a large extrapolation, so, the reliability is questionable. This led us to measure the effects of macromolecular crowding on its stability by chemical-induced denaturation of the protein using probes like circular dichroism and absorption spectroscopy in the presence of dextran 70 and ficoll 70 at various pHs (acidic: 6.0, almost neutral:7.0 and basic: 8.0). Observations showed that the degree of destabilization of myoglobin was greater due to ficoll 70 as compared to that of dextran 70 so it can be understood that the nature of the crowder or the shape of the crowder has an important role towards the stability of proteins. Additionally, the degree of destabilization was observed as pH dependent, however the pH dependence is different for different crowders. Furthermore, isothermal titration calorimetry and molecular docking studies confirmed that both the crowders (ficoll and dextran) bind to heme moiety of myoglobin and a single binding site was observed for each.
21 citations
02 Jun 2020
TL;DR: Molecular docking study showed that EG interacts with side chains of amino acid residues of Mb through van der Waals interactions and hydrogen bonding, which decreases the thermal stability of the protein, which increases with increasing concentration of EG.
Abstract: Investigation of changes in thermal stabilities and structures of proteins in the presence of different co-solutes (ligands) is an integral part in the basic research, discovery, and development of drugs. Ethylene glycol (EG) is known to be toxic and causes teratogenic, inducing primarily skeletal and external malformations and other diseases. The effect of EG on the structure and thermal stability of myoglobin (Mb) was studied using various spectroscopic techniques at pH 7.0 and two different temperatures. As revealed by circular dichroism, Trp fluorescence, nano-DSF, and absorption (UV and visible) measurements, EG (i) has no significant effect on secondary and tertiary structures of Mb at 25 °C, and (ii) it decreases the thermal stability of the protein, which increases with increasing concentration of EG. As revealed by ANS (8-anilino-1-naphthalene sulfonic acid) fluorescence measurements, heat-induced denatured protein has newly exposed hydrophobic patches that bind to ANS. Isothermal titration calorimetry revealed that the interaction between EG and Mb is temperature dependent; the preferential interaction of EG is entropy driven at low temperature, 298 K (25 °C), and it is enthalpy driven at higher temperature, 343 K (70 °C). Molecular docking study showed that EG interacts with side chains of amino acid residues of Mb through van der Waals interactions and hydrogen bonding.
19 citations
TL;DR: Hydropersulfides are found to react with oxymyoglobin similarly to other reducing species leading to a fleeting ferric myoglobin which is rapidly reduced to the ferrous form also by hydropersolfide.
18 citations
10 Jun 2020
TL;DR: Myoglobin exhibited low digestibility during pepsin and pancreatin digestion and only four hydrogen bonds existed in the myoglobin-pepsin complex, indicating more changes occurred in structure and digestibility for pancreatin digestibility.
Abstract: Myoglobin, a critical protein responsible for meat color, has been shown insusceptible to digestion. The underlying mechanism is not clear. The present study aimed to evaluate whether the structural properties of myoglobin are associated with its insusceptibility to digestion using spectroscopic and computational techniques. Myoglobin was degraded by only 7.03% by pepsin and 33.00% by pancreatin. The structure of myoglobin still maintained α-helix after the two-step digestion, with the exposure of some aromatic residues. In addition, molecular dynamics modeling suggested that hydrophobic amino acid residues (Phe 111, Leu 10, Ala 115, Pro 116) in pepsin and polar amino acid residues (Tyr 146, Thr 95) in myoglobin were found in the proximity of binding sites, which could result in the low digestibility of myoglobin. Our findings provide a new insight into the underlying mechanisms on the difficulty in digestion of myoglobin.
16 citations
TL;DR: Human myoglobin is successfully produced in the leaves of Nicotiana benthamiana by transient expression using a viral vector delivered by Agrobacterium tumefaciens, confirming that heme was incorporated and the protein was functional, with observed properties consistent with those of native myoglobins.
Abstract: Myoglobin is a heme-protein in the muscle of vertebrates with important functions in the oxygenation of tissues and as a regulator in nitric oxide signaling. Myoglobin from many species is also an important nutritional source of bioavailable iron. In this study, we have successfully produced human myoglobin in the leaves of Nicotiana benthamiana by transient expression using a viral vector delivered by Agrobacterium tumefaciens. Analyses confirmed that heme was incorporated and the protein was functional, with observed properties consistent with those of native myoglobins. A relatively high degree of purity could be achieved with low cost methods. The results show the high potential of plants as a production platform for heme proteins, a group of proteins of interest for iron nutrition applications and possible future pharmaceutical development.
14 citations
TL;DR: The role of the proteasome in the degradation of glycated proteins is highly dependent on the level of glycation and consequent protein unfolding.
TL;DR: Vibrational energy flow in myoglobin was examined using picosecond time-resolved anti-Stokes ultraviolet resonance Raman (UVRR) spectroscopy and it is found that energy flow through proteins is analogous to collisional exchange processes in solutions.
Abstract: Heme proteins are ideal systems to investigate vibrational energy flow at the atomic level. Upon photoexcitation, a large amount of excess vibrational energy is selectively deposited on heme due to extremely fast internal conversion. This excess energy is redistributed to the surrounding protein moiety and then to water. Vibrational energy flow in myoglobin (Mb) was examined using picosecond time-resolved anti-Stokes ultraviolet resonance Raman (UVRR) spectroscopy. We used the Trp residue directly contacting the heme group as a selective probe for vibrationally excited populations. Trp residues were placed at different position close to the heme by site-directed mutagenesis. This technique allows us to monitor the excess energy on residue-to-residue basis. Anti-Stokes UVRR measurements for Mb mutants suggest that the dominant channel for energy transfer in Mb is the pathway through atomic contacts between heme and nearby amino acid residues as well as that between the protein and solvent water. It is found that energy flow through proteins is analogous to collisional exchange processes in solutions.
TL;DR: The results highlighted the mechanistic aspects by which water soluble globular proteins interact with amphiphilic molecules of different functionalities and thus, helped to predict the interactions of both hemoglobin and myoglobin with the complex biological molecules possessing similar functionalities.
01 Jan 2020
TL;DR: This chapter will provide an overview of the factors involved in meat color by examining the biochemical processes that can influence the valance state and the ligand attached to myoglobin.
Abstract: Myoglobin is the primary sarcoplasmic protein that imparts meat color. Metmyoglobin reducing activity (MRA) and oxygen consumption (OC) are important biochemical processes that can influence the valance state and the ligand attached to myoglobin. Mitochondria remain active in postmortem muscle and can affect MRA and OC. Hence understanding the molecular basis of color depends on the biochemical changes in postmortem muscle. Further, lipid oxidation and postmortem aging time can decrease the activity of the enzymes and substrates required for MRA and OC. This chapter will provide an overview of the factors involved in meat color.
TL;DR: It is shown that nonbonded atomic contacts play an essential role in driving the displacement of a helix in picosecond-timescale primary structural changes following the dissociation of carbon monoxide from the heme group in myoglobin.
Abstract: The association and dissociation of small ligands regulate the functions of proteins through structural changes in the protein. Such structural changes propagate long distances, and this allostery plays a key role in molecular functions. However, the mechanism by which structural changes are transmitted is poorly understood. Here we show that nonbonded atomic contacts play an essential role in driving the displacement of a helix in picosecond time scale primary structural changes following the dissociation of carbon monoxide from the heme group in myoglobin. The present time-resolved ultraviolet resonance Raman study revealed that the amplitude of this helix displacement was reduced upon substitution of Val68, which contacts the heme in wild-type myoglobin, with a less bulky side chain (Ala). Our findings provided the first direct evidence that structural changes are transmitted not only by covalent bonds, salt bridges and hydrogen bonds but also by nonbonded atomic contacts in the primary protein response upon ligand dissociation. Furthermore, the present results indicate the importance of dense atomic packing in a protein structure for responding to the association and dissociation of small molecules. The high compactness of protein structures makes possible the propagation of structural changes, providing useful clues to the design of molecular machines.
TL;DR: Electrostatic forces show a critical function in stabilizing of this complex, which is in conforming to spectroscopic results, and Thermodynamics, molecular dynamics, and docking and the use of other spectroscopy procedures are employed.
Abstract: Spermine as polyamines can have interaction with the myoglobin (Mb). The intent of this pondering to evaluate the impact of spermine on Mb properties, for example, the structure and thermal stabili...
TL;DR: A novel clearance mechanism for muscle proteins by muscle cells is described, which could possibly be the dominant clearance mechanisms for cTn, myoglobin and other muscle damage biomarkers released by Muscle cells.
TL;DR: It is shown that both myoglobin and mitochondrial complex I expression are required for nitrite-dependent attenuation of cell death after anoxia/reoxygenation, expanding the understanding of myoglobin's role both as a nitrite reductase to a mediator of S-nitrosation and as a regulator of mitochondrial function.
TL;DR: It is confirmed that the experimental data are adequately reflected for acidic pH values by the non-linear PB model where the nominal molecule charge was calculated from the H++ model, and under physiological conditions prevailing, e.g. in skeletal muscles, the effective charge of the myoglobin molecule should practically vanish.
Abstract: All atom molecular dynamic modeling was applied in order to determine water molecule and electrolyte ion concentration profiles around and inside the myoglobin molecule at various pH values. Significant penetration of counter ions into the molecule was confirmed. The electric potential distribution within and outside the molecule was quantitatively described using the non-linear Poisson-Boltzmann (PB) approach. Using this model, calculations were performed, yielding the surface and zeta potential for various physicochemical parameters, comprising pH, the electric permittivity, the ion penetration depth and the protein volume fraction (crowding effect). The theoretical results were used for the interpretation of experimental data acquired under different ionic strengths and temperatures by electrophoretic mobility measurements. It is confirmed that the experimental data are adequately reflected for acidic pH values by the non-linear PB model where the nominal molecule charge was calculated from the H++ model. The deviations occurring for larger pH values were accounted for by considering additional non-electrostatic interactions stemming from the van der Waals and ion-induced dipole forces. In this way, it is both experimentally and theoretically confirmed that the effective charge of the myoglobin molecule in electrolyte solutions is considerably smaller than the nominal, structure-based, predicted charge. As a result, under physiological conditions prevailing, e.g. in skeletal muscles, the effective charge of the myoglobin molecule should practically vanish. One can expect that the approach developed in this work can be applied for predicting charging mechanisms of other protein molecules characterized by an analogous charge vs. pH characteristic, e.g., the SARS-CoV-2 virus spike proteins, and for soft particles with pH responsive characteristics.
TL;DR: It is confirmed that myoglobin produces HNO via the peroxidation of hydroxylamine with a great catalytic capacity and the mechanistic study allows us to state that the Mb ferryl state is the most likely intermediate that reacts with hydroXYlamine, yielding important evidence for endogenous HNO generation.
Abstract: Azanone (HNO, nitroxyl) is a highly reactive molecule that, in the past few years, has drawn significant interest because of its pharmacological properties. However, the understanding of how, when,...
TL;DR: In this paper, carbon nano-tubes as well as nano-composite consisting of carbon tubes and nano-gold particles after modification of aromatic substituent were proposed as carriers to immobilize myoglobin molecules for preparation of Myoglobin based electrodes.
20 Jun 2020
TL;DR: This study suggests that patients with T2DM had early limitation of oxygen extraction and lower capacity of oxygenated myoglobin dissociation in the VL muscle.
Abstract: PURPOSE It is clinically important to elucidate the precise mechanism of exercise intolerance in patients with type 2 diabetes (T2DM). The aim of this study was to examine whether there is a difference in the time course change of the oxygenation in the vastus lateralis (VL) muscle during submaximal incremental cycling exercise between patients with T2DM and age-matched healthy subjects. METHODS Nine elderly men with T2DM and 10 age-matched healthy men (CON) participated in this study. All participants performed an incremental cycling exercise.Total, deoxygenated and oxygenated hemoglobin/myoglobin in the VL muscle were assessed using near-infrared spectroscopy, and cardiorespiratory response was also evaluated during the exercise. RESULTS There were no significant differences in the time course changes of deoxygenated hemoglobin/myoglobin between groups ( p > 0.05). However, the oxygenated hemoglobin/myoglobin in T2DM was significantly higher than that in CON at an intensity above ventilatory threshold during the incremental cycling exercise ( p< 0.05). CONCLUSION This study suggests that patients with T2DM had early limitation of oxygen extraction and lower capacity of oxygenated myoglobin dissociation in the VL muscle. The fact that patients with T2DM showed different oxygen kinetics in a peripheral tissue from healthy subjects may partly explain the potential mechanisms of exercise intolerance in T2DM.
TL;DR: In this paper, the effects of free excited tryptophan on redox reaction of myoglobin were monitored by laser flash photolysis, and the possible photo induced reaction mechanisms of DeoxyMb, MbO2, MetMb with and without free tryphophan were also proposed.
Abstract: Despite being one of the most studied proteins in biology, the photolysis mechanism of myoglobin heme affected by endogenous substances free amino acids is still in controversy. The transient absorption and kinetic processes of photo-excited myoglobin in three forms and the effects of free excited tryptophan on redox reaction of myoglobin were monitored by laser flash photolysis. With dual energy superposition of direct light irradiation and indirect energy transferred from the free excited tryptophan, the variation value in optical density (ΔOD) of MetMb increased by 66.7%, from 0.9 to 1.5. The ΔOD value of MbO2 in ferrous form increased from 0.9 to 1.25, while the ΔOD value of DeoxyMb increased from 0.75 to 1.2. The decay time of excited DeoxyMb was prolonged obviously with the excited tryptophan, while the decay time of excited MbO2 and MetMb was shortened significantly. The excited tryptophan could promote laser induced reaction processes of myoglobin in different forms by intermolecular energy transfer to one final similar photo reaction state. The possible photo induced reaction mechanisms of DeoxyMb, MbO2, MetMb with and without free tryptophan were also proposed.
TL;DR: A gas-phase resonance Raman spectroscopy combined with IR-laser ablation of a droplet beam was developed, which allowed it to elucidate local structures around chromophores in gas- phase proteins and DNAs.
Abstract: Gas phase spectroscopy is a powerful tool for examining fundamental chemical structures and properties free from solvent molecules. We developed a gas-phase resonance Raman spectroscopy combined with IR-laser ablation of a droplet beam, which allowed us to elucidate local structures around chromophores in gas-phase proteins and DNAs. To demonstrate the potential of this approach, we applied this method to myoglobin, one of the heme proteins, and elucidated its structures in the gas phase and in aqueous solution. The experimental spectra are compared with calculated spectra of stable heme structures for the structural determination. These results show the oxidation/spin states of the Fe atom in myoglobin in the gas phase and were compared with the aqueous solution from the obtained resonant Raman spectra. The present method gives an important tool to investigate the gas-phase structure of large biomolecules.
TL;DR: This work reports the first crystal structure of a wild-type heme protein adduct of any amphetamine metabolite and provides a framework for further studies of AmphNHOH/AmphNO interactions with Hb and Mb as viable processes that potentially contribute to the overall biological inorganic chemistry of amphetamine drugs.
TL;DR: The glycation of myoglobin (Mb) by physico-chemical techniques and the resulting immunogenicity by ELISA techniques is studied and the level of free lysine and arginine determined was found to be significantly decreased indicating the establishment of the glycation reaction.
TL;DR: AUC and DLS data agree with SDS-PAGE in showing that the apo-HbGp undergoes dissociation into the d and abc subunits, and two populations are present in solution: one with a diameter around 6.0 nm, identified with the dissociated species, and a second one with diameter 100–180 nm, due to aggregated protein.
Abstract: The structural study of small heme-containing proteins, such as myoglobin, in the apo-form lacking heme has been extensively described, but the characterization and stability of the giant Glossoscolex paulistus hemoglobin (HbGp), in the absence of heme groups, has not been studied. Spectroscopic data show efficient extraction of the heme groups from the hemoglobin, with relatively small secondary and tertiary structural changes in apo-HbGp noticed compared to oxy-HbGp. Electrophoresis shows a partial precipitation of the trimer abc (significantly lower intensity of the corresponding band in the gel), due to extraction of heme groups, and the predominance of the intense monomeric d band, as well as of two linker bands. AUC and DLS data agree with SDS-PAGE in showing that the apo-HbGp undergoes dissociation into the d and abc subunits. Subunits d and abc are characterized by sedimentation coefficients and percentage contributions of 2.0 and 3.0 S and 76 and 24%, respectively. DLS data suggest that the apo-HbGp is unstable, and two populations are present in solution: one with a diameter around 6.0 nm, identified with the dissociated species, and a second one with diameter 100–180 nm, due to aggregated protein. Finally, the presence of urea promotes the exposure of the fluorescent probes, extrinsic ANS and intrinsic protein tryptophans to the aqueous solvent due to the unfolding process. An understanding of the effect of heme extraction on the stability of hemoproteins is important for biotechnological approaches such as the introduction of non-native prosthetic groups and development of artificial enzymes with designed properties.
01 Jan 2020
TL;DR: In this chapter, an overview is given about basic mechanisms on how energy metabolism can be disturbed, protective systems are presented, and links are provided to diseases associated with deficits in energy supply.
Abstract: In animals and humans, dioxygen and glucose are the main substrates used for generation of universal energy equivalents in form of adenosine triphosphate. Uptake, transport, and utilization of dioxygen are highly regulated as these processes might be disturbed by the release of O2-binding proteins from red blood and muscle cells and the formation of highly cytotoxic metabolites such as methemoglobin, free hemoglobin, free myoglobin, and free ferric protoporphyrin IX, shortly known as free heme. In healthy individuals, glucose metabolism is also well controlled because of numerous chemical side reactions of glucose, which affect most of all the metabolism of insulin-independent cells under hyperglycemic conditions. Moreover, mitochondria can be a source for reactive species and damaging reactions. In this chapter, an overview is given about basic mechanisms on how energy metabolism can be disturbed, protective systems are presented, and links are provided to diseases associated with deficits in energy supply.
TL;DR: Myoglobin immunohistochemistry of renal tissues, serum creatine kinase, urine myoglobin analysis and muscle histopathology are the laboratory tests that should be considered at autopsy where rhabdomyolysis is suspected.
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TL;DR: The structural dynamics and vibrational spectroscopy of S-nitrosylation in the condensed phase are investigated for the methyl-capped cysteine model system and for myoglobin and the finding of stable cis- and trans-MbSNO agrees with experimental findings on other proteins.
Abstract: S-nitrosylation, the covalent addition of NO to the thiol side chain of cysteine, is an important post-transitional modification that can alter the function of various proteins. The structural dynamics and vibrational spectroscopy of S-nitrosylation in the condensed phase is investigated for the methyl-capped cysteine model system and for myoglobin. Using conventional point charge and physically more realistic multipolar force fields for the -SNO group it is found that the SN- and NO-stretch and the SNO-bend vibrations can be located and distinguished from the other protein modes for simulations of MbSNO at 50 K. The finding of stable cis- and trans-MbSNO is consistent with experiments on other proteins as is the observation of buried -SNO. For MbSNO the observed relocation of the EF loop in the simulations by $\sim 3$ A\/ is consistent with the available X-ray structure and the conformations adopted by the -SNO label are in good overall agreement with the X-ray structure. Despite the larger size of the -SNO group, MbSNO is found to recruit more water molecules within 10 A\/ of the modification site than WT Mb due to the stronger electrostatics. Similarly, when comparing the hydration between the A- and H-helices they differ by up to 30 \% between WT and MbSNO. This suggests that local hydration can also be significantly modulated through nitrosylation.