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Scientific Reports Nov 2018Extant cetaceans, such as sperm whale, acquired the great ability to dive into the ocean depths during the evolution from their terrestrial ancestor that lived about 50...
Extant cetaceans, such as sperm whale, acquired the great ability to dive into the ocean depths during the evolution from their terrestrial ancestor that lived about 50 million years ago. Myoglobin (Mb) is highly concentrated in the myocytes of diving animals, in comparison with those of land animals, and is thought to play a crucial role in their adaptation as the molecular aqualung. Here, we resurrected ancestral whale Mbs, which are from the common ancestor between toothed and baleen whales (Basilosaurus), and from a further common quadrupedal ancestor between whale and hippopotamus (Pakicetus). The experimental and theoretical analyses demonstrated that whale Mb adopted two distinguished strategies to increase the protein concentration in vivo along the evolutionary history of deep sea adaptation; gaining precipitant tolerance in the early phase of the evolution, and increase of folding stability in the late phase.
Topics: Amino Acid Sequence; Animals; Evolution, Molecular; Extinction, Biological; Myoglobin; Oxygen; Phylogeny; Probability; Whales
PubMed: 30442991
DOI: 10.1038/s41598-018-34984-6 -
The Journal of Biological Chemistry Nov 1998Muscle injury (rhabdomyolysis) and subsequent deposition of myoglobin in the kidney causes renal vasoconstriction and renal failure. We tested the hypothesis that...
Muscle injury (rhabdomyolysis) and subsequent deposition of myoglobin in the kidney causes renal vasoconstriction and renal failure. We tested the hypothesis that myoglobin induces oxidant injury to the kidney and the formation of F2-isoprostanes, potent renal vasoconstrictors formed during lipid peroxidation. In low density lipoprotein (LDL), myoglobin induced a 30-fold increase in the formation of F2-isoprostanes by a mechanism involving redox cycling between ferric and ferryl forms of myoglobin. In an animal model of rhabdomyolysis, urinary excretion of F2-isoprostanes increased by 7.3-fold compared with controls. Administration of alkali, a treatment for rhabdomyolysis, improved renal function and significantly reduced the urinary excretion of F2-isoprostanes by approximately 80%. EPR and UV spectroscopy demonstrated that myoglobin was deposited in the kidneys as the redox competent ferric myoglobin and that it's concentration was not decreased by alkalinization. Kinetic studies demonstrated that the reactivity of ferryl myoglobin, which is responsible for inducing lipid peroxidation, is markedly attenuated at alkaline pH. This was further supported by demonstrating that myoglobin-induced oxidation of LDL was inhibited at alkaline pH. These data strongly support a causative role for oxidative injury in the renal failure of rhabdomyolysis and suggest that the protective effect of alkalinization may be attributed to inhibition of myoglobin-induced lipid peroxidation.
Topics: Animals; Bicarbonates; Dinoprost; Disease Models, Animal; Electron Spin Resonance Spectroscopy; Glycerol; Humans; Hydrogen-Ion Concentration; Kidney; Lipoproteins, LDL; Metmyoglobin; Myoglobin; Oxidation-Reduction; Potassium Compounds; Rats; Renal Insufficiency; Rhabdomyolysis; Spectrophotometry; Vasoconstriction
PubMed: 9822635
DOI: 10.1074/jbc.273.48.31731 -
Structure (London, England : 1993) Apr 1995Insufficient sampling of conformational sub-states by current molecular dynamics simulations accounts for deficiencies in representations of the fluctuating interatomic... (Review)
Review
Insufficient sampling of conformational sub-states by current molecular dynamics simulations accounts for deficiencies in representations of the fluctuating interatomic separations in macromolecules.
Topics: Computer Simulation; Crystallography, X-Ray; Macromolecular Substances; Models, Molecular; Molecular Conformation; Motion; Myoglobin; Protein Conformation
PubMed: 7613862
DOI: 10.1016/s0969-2126(01)00163-0 -
Biochemistry. Biokhimiia Feb 2018In this review, we shortly summarize the data of our studies (and also corresponding studies of other authors) on the new mechanism of myoglobin (Mb) deoxygenation in a... (Review)
Review
In this review, we shortly summarize the data of our studies (and also corresponding studies of other authors) on the new mechanism of myoglobin (Mb) deoxygenation in a cell, according to which Mb acts as an oxygen transporter, and its affinity for the ligand, like in other transporting proteins, is regulated by the interaction with the target, in our case, mitochondria (Mch). We firstly found that contrary to previously formulated and commonly accepted concepts, oxymyoglobin (MbO) deoxygenation occurs only via interaction of the protein with respiring mitochondria (low p values are necessary but not sufficient for this process to proceed). Detailed studies of the mechanism of Mb-Mch interaction by various physicochemical methods using natural and artificial bilayer phospholipid membranes showed that: (i) the rate of MbO deoxygenation in the presence of respiring Mch fully coincides with the rate of O2 uptake by mitochondria from a solution irrespectively of their state (native coupled, freshly frozen, or FCCP-uncoupled), i.e. it is determined by the respiratory activity of Mch; (ii) Mb nonspecifically binds to membrane phospholipids of the outer mitochondrial membrane, while any Mb-specific protein or phospholipid sites on it are lacking; (iii) oxygen uptake by Mch from a solution and the uptake of Mb-bound oxygen are two different processes, as their rates are differently affected by proteins (e.g. lysozyme) that compete with MbO for binding to the mitochondrial membrane; (iv) electrostatic forces significantly contribute to the Mb-membrane interactions; the dependence of these interactions on ionic strength is provided by the local electrostatic interactions between anionic groups of phospholipids (the heads) and invariant Lys and Arg residues near the Mb heme pocket; (v) interactions of Mb with phospholipid membranes promote conformational changes in the protein, primarily in its heme pocket, without significant alterations in the protein secondary and tertiary structures; and (vi) Mb-membrane interactions lead to decrease in the affinity of myoglobin for O2, which could be monitored by the increase in the MbO autooxidation rate under aerobic conditions and under anaerobic ones, by the shift in the MbO/Mb(2) equilibrium towards the ligand-free protein. The decrease in the affinity of Mb for the ligand should facilitate O2 dissociation from MbO at physiological p values in cells.
Topics: Animals; Kinetics; Liver; Mitochondria; Mitochondrial Membranes; Models, Molecular; Myoglobin; Oxygen; Rats
PubMed: 29618303
DOI: 10.1134/S0006297918020098 -
BMC Complementary and Alternative... Jan 2018Fructose-mediated protein glycation (fructation) has been linked to an increase in diabetic and cardiovascular complications due to over consumption of high-fructose...
BACKGROUND
Fructose-mediated protein glycation (fructation) has been linked to an increase in diabetic and cardiovascular complications due to over consumption of high-fructose containing diets in recent times. The objective of the present study is to evaluate the protective effect of (R)-α-lipoic acid (ALA) against fructose-induced myoglobin fructation and the formation of advanced glycation end products (AGEs) in vitro.
METHODS
The anti-glycation activity of ALA was determined using the formation of AGEs fluorescence intensity, iron released from the heme moiety of myoglobin and the level of fructosamine. The fructation-induced myoglobin oxidation was examined using the level of protein carbonyl content and thiol group estimation.
RESULTS
The results showed that co-incubation of myoglobin (1 mg/mL), fructose (1 M) and ALA (1, 2 and 4 mM) significantly inhibited the formation of AGEs during the 30 day study period. ALA markedly decreased the levels of fructosamine, which is directly associated with the reduction of AGEs formation. Furthermore, ALA significantly reduced free iron release from myoglobin which is attributed to the protection of myoglobin from fructose-induced glycation. The results also demonstrated a significant protective effect of ALA on myoglobin oxidative damages, as seen from decreased protein carbonyl content and increased protein thiols.
CONCLUSION
These findings provide new insights into the anti-glycation properties of ALA and emphasize that ALA supplementation is beneficial in the prevention of AGEs-mediated diabetic and cardiovascular complications.
Topics: Animals; Fructose; Glycation End Products, Advanced; Glycosylation; Myoglobin; Thioctic Acid
PubMed: 29334926
DOI: 10.1186/s12906-017-2076-6 -
The International Journal of... 2009The globin family, including hemoglobin, myoglobin, neuroglobin and cytoglobin, plays an important role in oxygen storage and delivery. Myoglobin has been shown to be...
The globin family, including hemoglobin, myoglobin, neuroglobin and cytoglobin, plays an important role in oxygen storage and delivery. Myoglobin has been shown to be necessary for cardiac function during development, but no information is currently available on the developmental regulation of myoglobin gene expression during embryogenesis. In this study, we used whole mount in situ hybridization to visualize myoglobin mRNA expression during zebrafish development. Our results show for the first time the spatial and temporal gene expression pattern of myoglobin during embryogenesis. Myoglobin was expressed as a maternal RNA and ubiquitous expression was observed until the end of gastrulation. At later stages of development, we discovered novel expression domains for myoglobin, including several non-muscular ones. Environmental stresses, like low oxygen tension (hypoxia) can lead to a developmental delay in zebrafish embryos. We show here that hypoxic stress induces myoglobin expression in skeletal muscle cells of anterior somites and in the dorsal aorta of zebrafish larvae. Finally, we analyzed the role of myoglobins in development by targeted gene knock-down. Silencing myoglobin in zebrafish embryos with gene-specific morpholinos led to a dose dependent curvature, vascular defects, enlarged pericardia and reduction of the gut. In conclusion, our results indicate that myoglobin plays a crucial role in zebrafish development and is important for angiogenesis and gut development.
Topics: Animals; Embryo, Nonmammalian; Gene Expression Regulation, Developmental; Genome; Humans; Myoglobin; Phylogeny; Zebrafish
PubMed: 19378255
DOI: 10.1387/ijdb.082651dv -
Angewandte Chemie (International Ed. in... Mar 2021The difluoromethyl (CHF ) group has attracted significant attention in drug discovery and development efforts, owing to its ability to serve as fluorinated bioisostere...
The difluoromethyl (CHF ) group has attracted significant attention in drug discovery and development efforts, owing to its ability to serve as fluorinated bioisostere of methyl, hydroxyl, and thiol groups. Herein, we report an efficient biocatalytic method for the highly diastereo- and enantioselective synthesis of CHF -containing trisubstituted cyclopropanes. Using engineered myoglobin catalysts, a broad range of α-difluoromethyl alkenes are cyclopropanated in the presence of ethyl diazoacetate to give CHF -containing cyclopropanes in high yield (up to >99 %, up to 3000 TON) and with excellent stereoselectivity (up to >99 % de and ee). Enantiodivergent selectivity and extension of the method to the stereoselective cyclopropanation of mono- and trifluoromethylated olefins was also achieved. This methodology represents a powerful strategy for the stereoselective synthesis of high-value fluorinated building blocks for medicinal chemistry, as exemplified by the formal total synthesis of a CHF isostere of a TRPV1 inhibitor.
Topics: Biocatalysis; Cyclopropanes; Hydrocarbons, Fluorinated; Molecular Structure; Myoglobin; Stereoisomerism
PubMed: 33337576
DOI: 10.1002/anie.202015895 -
Critical Care (London, England) Jan 2021Rhabdomyolysis is frequently occurring in critically ill patients, resulting in a high risk of acute kidney injury (AKI) and potentially permanent kidney damage due to... (Observational Study)
Observational Study
BACKGROUND
Rhabdomyolysis is frequently occurring in critically ill patients, resulting in a high risk of acute kidney injury (AKI) and potentially permanent kidney damage due to increased myoglobin levels. The extracorporeal elimination of myoglobin might be an approach to prevent AKI, but its molecular weight of 17 kDa complicates an elimination with conventional dialysis membranes. Question of interest is, if myoglobin can be successfully eliminated with the cytokine adsorber Cytosorb® (CS) integrated in a high-flux dialysis system.
METHODS
Patients were included between 10/2014 and 05/2020 in the study population if they had an anuric renal failure with the need of renal replacement therapy, if CS therapy was longer than 90 min and if myoglobin level was > 5.000 ng/ml before treatment. The measurement times of the laboratory values were: d-1 = 24-36 h before CS, d0 = shortly before starting CS and d1 = 12-24 h after starting CS treatment. Statistical analysis were performed with Spearman's correlation coefficient, Wilcoxon test with associated samples and linear regression analysis.
RESULTS
Forty-three patients were included in the evaluation (median age: 56 years, 77% male patients, 32.6% ECMO therapy, median SAPS II: 80 points and in-hospital mortality: 67%). There was a significant equilateral correlation between creatine kinase (CK) and myoglobin at all measurement points. Furthermore, there was a significant reduction of myoglobin (p = 0.03, 95% confidence interval (CI): - 9030, - 908 ng/ml) during CS treatment, with a median relative reduction of 29%. A higher median reduction of 38% was seen in patients without ongoing rhabdomyolysis (CK decreased during CS treatment, n = 21). In contrast, myoglobin levels did not relevantly change in patients with increasing CK and therefore ongoing rhabdomyolysis (n = 22, median relative reduction 4%). Moreover, there was no significant difference in myoglobin elimination in patients with and without ECMO therapy.
CONCLUSION
Blood purification with Cytosorb® during high-flux dialysis led to a significant reduction of myoglobin in patients with severe rhabdomyolysis. The effect might be obscured by sustained rhabdomyolysis, which was seen in patients with rising CK during treatment. Prospective clinical trials would be useful in investigating its benefits in avoiding permanent kidney damage.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Critical Illness; Cytokines; Female; Germany; Humans; Male; Middle Aged; Myoglobin; Prospective Studies; Renal Reabsorption; Renal Replacement Therapy; Retrospective Studies; Rhabdomyolysis
PubMed: 33509234
DOI: 10.1186/s13054-021-03468-x -
Biochemistry and Molecular Biology... 2015We have developed a multiweek laboratory project in which students isolate myoglobin and characterize its structure, function, and redox state. The important laboratory...
We have developed a multiweek laboratory project in which students isolate myoglobin and characterize its structure, function, and redox state. The important laboratory techniques covered in this project include size-exclusion chromatography, electrophoresis, spectrophotometric titration, and FTIR spectroscopy. Regarding protein structure, students work with computer modeling and visualization of myoglobin and its homologues, after which they spectroscopically characterize its thermal denaturation. Students also study protein function (ligand binding equilibrium) and are instructed on topics in data analysis (calibration curves, nonlinear vs. linear regression). This upper division biochemistry laboratory project is a challenging and rewarding one that not only exposes students to a wide variety of important biochemical laboratory techniques but also ties those techniques together to work with a single readily available and easily characterized protein, myoglobin.
Topics: Biochemistry; Humans; Models, Molecular; Myoglobin; Structure-Activity Relationship
PubMed: 25726810
DOI: 10.1002/bmb.20845 -
Anais Da Academia Brasileira de Ciencias 2016Iron is an important trace element for proper cell functioning. It is present in cytochromes, hemoglobin and myoglobin (Mb), where it binds to oxygen. It is also an...
Iron is an important trace element for proper cell functioning. It is present in cytochromes, hemoglobin and myoglobin (Mb), where it binds to oxygen. It is also an electron acceptor in the respiratory chain. Mb is an 18 kDa heme-protein, highly expressed in skeletal muscle and heart. The expression of several genes involved in the metabolism of iron is post-transcriptionally regulated by this element. Iron was shown to interfere with the polyadenylation step, modifying their poly (A) tail length and, as a consequence, their stability and translation rate. The aim of this study was to investigate whether iron supplementation or long and short-term restriction affects Mb gene and protein expression, as well as Mb mRNA poly(A) tail length, in cardiac and skeletal muscles of rats. Long-term iron restriction caused an increase in Mb gene and protein expression in Soleus muscle. No changes were observed in extensor digitorum longus muscle and heart. Short-term iron supplementation after iron deprivation did not alter Mb gene expression and mRNA poly(A) tail length in all tissues studied. These results indicate that Mb gene and protein expression is upregulated in response to iron deprivation, an effect that is tissue-specific and seems to occur at transcriptional level.
Topics: Animals; Gene Expression; Iron; Muscle, Skeletal; Myoglobin; RNA, Messenger; Rats
PubMed: 27991963
DOI: 10.1590/0001-3765201620160173