Showing papers on "Myoglobin published in 1986"
TL;DR: The structure of carbon-monoxy (Fe II) myoglobin at 260 K has been solved at a resolution of 1.5 A byX-ray diffraction and a model refined against the X-ray data by restrained least-squares, suggesting a mechanism for ligand entry.
466 citations
TL;DR: The stability of the structure of sperm whale metmyoglobin has been studied in various solutions by scanning microcalorimetry, light absorption, circular dichroism, nuclear magnetic resonance spectroscopy and viscosimetry and it has been shown that in 10 mM-sodium acetate solutions the protein molecule undergoes a reversible conformational transition into a non-compact disordered state.
381 citations
TL;DR: The water of hydration in myoglobin crystals and solutions was studied at subzero temperatures by calorimetry and infrared spectroscopy and a hydrogen bond network model is proposed to explain these features.
213 citations
TL;DR: The overall quantum yield of the ligand complex is determined primarily by the competition between the rate of iron-ligand bond formation from the initial photoproduct, kB----MbX, and the rate-limiting step in the overall association reaction starting from ligand in solution is the formation of state B.
133 citations
TL;DR: Simulation of the interaction of xenon atoms with the interior of the myoglobin molecule indicates that insertion of the first xenon atom causes a perturbation of the protein conformation that facilitates insertion of one or more additional xenona.
Abstract: The interaction of xenon atoms with the interior of the myoglobin molecule has been simulated by molecular dynamics calculations. The standard free energy of binding has been computed from a simulation in which a forcing potential was applied; computed and experimental values differ by only 2 kJ/mole. In agreement with experimental evidence, the simulations indicate that insertion of the first xenon atom causes a perturbation of the protein conformation that facilitates insertion of one or more additional xenona.
109 citations
TL;DR: The molecular characterization of the two structural forms indicates that acids disorganize the 80-146 molecular domain identified in the myoglobin molecule to a great extent with respect to that induced by low guanidine concentration, whereas the structure of the 1-79 domain appears to be quite similar in the two molecular forms.
91 citations
TL;DR: In this paper, the authors used resonance Raman spectroscopy and isotopic labeling techniques to unambiguously assign the dioxygen stretching frequency (vo-o) in the substrate-bound oxygenated complex of cytochrome P-450cam.
82 citations
TL;DR: Comparison of the structures of various peroxidase and myoglobin compounds points out systematic differences that may explain the catalytic activity of the pi cation radical as well as some of the differences between globins and heme enzymes.
Abstract: X-ray absorption studies of myoglobin peroxide show that although it is not identical with compound I or II of horseradish peroxidase [Chance, B., Powers, L., Ching, Y., Poulos, T., Yamazaki, I., & Paul, K. G. (1984) Arch. Biochem. Biophys. 235, 596-611], it has some structural features in common with both. As seen in compound I, the Fe-O distance is short, but the iron-pyrrole nitrogen distance is contracted with a longer iron-histidine distance like compound II. The iron has a higher oxidation state than Fe3+, suggesting an oxyferryl ion type species. Comparison of the structures of various peroxidase and myoglobin compounds points out systematic differences that may explain the catalytic activity of the pi cation radical as well as some of the differences between globins and heme enzymes.
77 citations
TL;DR: The discovery that a leucine residue which is facing inwards in the crystal structure is critical for the binding of antibody to the peptide suggests that binding between native antigen and antibody can require a restructuring of the native antigen.
68 citations
01 Jan 1986
TL;DR: Raman spectroscopy and isotopic labeling techniques are used to unambiguously assign the dioxygen stretching frequency (vo-o) in the substrate-bound oxygenated complex of cytochrome P-450cam, and it is noted that the effect of the "extra" electron in the nitrogen base Co(II) oxy complexes, in some ways, parallels theeffect of the lone pair electrons of thiolate in the oxy-P- 450cam complex.
Abstract: in the P-450,, system (1140 cm") is in remarkable agreement with recent studies of thiolate heme model compounds. The general features of the oxy-P-450,, Raman spectra are tabulated and comparisons are made with the oxy complexes of hemoglobin, myoglobin, and various model compounds. Most of the results are qualitatively explained by consideration of electron donation into the r,*(O,)/&(M) orbitals of the oxygenated complex (M
63 citations
TL;DR: The approximate constancy of the width of the hydration shell for two molecules as dissimilar in size as LDL and myoglobin confirms that the proportion of water existing as water of hydration in a biological solution depends critically on the size of the macromolecules as well as on their concentration.
Abstract: The dielectric behavior of the aqueous solutions of three widely differing macromolecules has been investigated: myoglobin, polyvinylpyrrolidone (PVP), and human serum low-density lipoprotein (LDL). It was not possible to interpret unambiguously the dielectric properties of the PVP solution in terms of water structure. The best interpretation of the dielectric data on the myoglobin and LDL solutions was that, in both cases, the macromolecule attracts a layer of water of hydration one or two water molecules in width. For LDL, this corresponds to a hydration factor of only 0.05 g/g, whereas for myoglobin the figure is nearer 0.6 g/g. With myoglobin, part of the water of hydration exhibits its dispersion at frequencies of a few GHz, and the rest disperses at lower frequencies, perhaps as low as 10-12 MHz. The approximate constancy of the width of the hydration shell for two molecules as dissimilar in size as LDL and myoglobin confirms that the proportion of water existing as water of hydration in a biological solution depends critically on the size of the macromolecules as well as on their concentration.
TL;DR: A theoretical two-dimensional model is used to investigate oxygen gradients in a red skeletal muscle fiber and predicts that maximal oxygen consumption can proceed with a relatively flat oxygen tension drop from fiber periphery to core over a large range for diffusion coefficients.
TL;DR: The complete amino acid sequence of the myoglobin from Dolabella auricularia, a common gastropodic mollusc on the Japanese coast, has been determined and shows strong homology with those of Aplysia myoglobins.
TL;DR: The fluorescence intensity measurements permit an estimation of the increase in the TRY-heme distance in the high pressure state, which indicates that several high pressure states occur.
Journal Article•
TL;DR: In the total group of patients, absolute values of the laboratory indices did not correlate well with strength except in the case of serum myoglobin, where there was a significant inverse relationship.
Abstract: Strength of the quadriceps and hamstring groups was biomechanically assessed in terms of isometric torque production in 14 patients with inflammatory myopathy. Eleven had polymyositis and 3, dermatomyositis. Determinations of serum creatine kinase, lactate dehydrogenase, transaminase, and myoglobin were simultaneously obtained over an average period of observation of 1.8 years. In certain individual patients, there were significant correlations between laboratory indices and strength during the entire course of illness. In others, this was not the case. In the total group of patients, absolute values of the laboratory indices did not correlate well with strength except in the case of serum myoglobin, where there a significant inverse relationship. Logarithmic transformations of the laboratory data increased the inverse correlations. High strength and low myoglobin were related to high prednisone dose. Since laboratory guides are not always related to disease activity, quantitative assessment of muscle strength is necessary.
TL;DR: The photoproduct of carbon monoxide myoglobin generated at 4 K and lower has a resonance Raman spectrum characteristic of a high-spin heme but in which the high-frequency core size-sensitive lines are at lower frequency than those in the deoxy preparation, and the core size exceeds that in deoxymyoglobin.
Abstract: The photoproduct of carbon monoxide myoglobin generated at 4 K and lower has a resonance Raman spectrum characteristic of a high-spin heme but in which the high-frequency core size-sensitive lines are at lower frequency than those in the deoxy preparation. Such differences are not detected in the photoproduct generated at higher temperatures (50 K) or in that generated at room temperature with 10-nsec pulses. The data indicate that at the low temperature (4 K), the heme in the photoproduct is not fully relaxed, and from the data we conclude that the photoproduct has an expanded porphyrin core. We infer that the core size exceeds that in deoxymyoglobin because the rigid protein prevents the highspin iron atom from moving to its full out-of-plane displacement at the very low temperatures.
TL;DR: It is shown that myoglobin gene transcription and the appearance of myoglobin occur very early in myogenesis, in both humans and mice, and both rat and mouse embryonic myoblasts accumulate myoglobin mRNA on fusion and differentiation in vitro.
Abstract: We showed that myoglobin gene transcription and the appearance of myoglobin occur very early in myogenesis, in both humans and mice. In contrast to the contractile protein genes, there is a subsequent increase of 50- to 100-fold in myoglobin mRNA and protein levels during later muscle development. Myoglobin and myoglobin mRNA are present at elevated levels in fetal heart and are also detectable at low levels in adult smooth muscle. The absolute level of myoglobin mRNA in highly myoglobinized seal muscle is very high [2.8% of the total population of poly(A)+ RNAs]. Levels of myoglobin in seal skeletal muscle and in various human muscle types appear to be determined by the size of the myoglobin mRNA pool. In contrast, low levels of myoglobin in mouse skeletal muscle are not apparently correlated with low levels of myoglobin mRNA. As expected from the early appearance of myoglobin mRNA in embryonic skeletal muscle, both rat and mouse embryonic myoblasts accumulate myoglobin mRNA on fusion and differentiation in vitro.
01 Jan 1986
TL;DR: This article showed that myoglobin gene transcription and the appearance of myoglobin occur very early in myogenesis, in both humans and mice, and there is a subsequent increase of 50-to100-fold in myoglobin mRNA and protein levels during later muscle development.
Abstract: We showedthatmyoglobin gene transcription andtheappearanceofmyoglobin occur very earlyin myogenesis, inbothhumansandmice. Incontrast tothecontractile protein genes,there isa subsequent increase of50-to100-fold inmyoglobin mRNA andprotein levels during later muscle development. Myoglobin andmyoglobin mRNA arepresent atelevated levels infetal heart andarealso detectable atlowlevels inadult smooth muscle. Theabsolute level ofmyoglobin mRNA inhighly myoglobinized seal muscle isveryhigh[2.8% ofthetotal population ofpoly(A)+ RNAs]. Levels ofmyoglobin inseal skeletal muscle andinvarious human muscle types appeartobedetermined bythesize ofthemyoglobin mRNA pool. Incontrast, lowlevels of myoglobin inmouse skeletal muscle arenotapparently correlated withlowlevels ofmyoglobin mRNA.As expected fromtheearly appearanceofmyoglobin mRNA inembryonic skeletal muscle, bothratandmouse embryonic myoblasts accumulate myoglobin mRNA on fusion anddifferentiation invitro. Theexpression ofthemuscle contractile protein genesis an attractive systemforthestudyoftheinduction of tissue-specific genesincellular differentiation, andcan be modeledinculture bydifferentiation ofskeletal muscle myoblasts toformmultinucleate contractile myotubes. Manystudies haveshownthatcontractile protein genesare activated after myoblast fusion (seereference 9).These include skeletal andcardiac muscle ca-actins (5), myosin light andheavychains (42), andtroponins andtropomyosins (15). Mostoftheseproteins areencodedbymultigene families (23, 46), individual membersofwhichexhibit tissue-specific anddevelopmentally regulated expression. Forexample, fetal- andneonatal-specific isoforms havebeenfoundfor myosinheavychain (42), andthere areintotal atleast 10 isoforms ofthis protein expressed inmammalian tissues (10). Incontrast tothemuscle-specific contractile protein genes,muchlessisknownabouttheexpression ofother muscle-specific genes during myogenesis. An example of sucha protein ismyoglobin, theprincipal hemoprotein of vertebrate muscle, whichservestofacilitate diffusion of oxygentothemuscle mitochondria (43). Elevated levels of myoglobin arefoundinskeletal muscle ofdiving mammals andbirds andinsome mammalsadapted tohypoxic subterraneanorhigh-altitude environments (11, 26,34). Levels in some aquatic species arehighenough toactas a significant oxygenstoreduring diving (44) andtherefore represent an evolutionary adaptation toadiving physiology. Thereisalso a correlation between muscle typeandmyoglobin content, suchthatslow(orred)muscles contain a higher concentrationofmyoglobin thanfast(white) muscles (36). Little is knownabouttheregulation ofmyoglobin synthesis during muscledevelopment. Inhumansandsheep, myoglobin accumulates incardiac muscleearly infetal development, butwas notthought toappearinskeletal muscle until later in gestation (27, 38). Myoglobin genesaredistant membersoftheglobin gene superfamily, theduplication eventleading tothedivergence
TL;DR: In this paper, the Kubelka-Munk theory was applied to determine relative concentrations of muscle pigments in packaged refrigerated beef using reflectance spectrophotometry, and the effects of storage temperatures and gaseous film permeabilities on myoglobin oxygenation and oxidation rates were analyzed in unsterile beef tissue.
Abstract: Equations derived from Kubelka-Munk theory were applied to determine relative concentrations of muscle pigments in packaged refrigerated beef using reflectance spectrophotometry. Effects of storage temperatures and gaseous film permeabilities on myoglobin oxygenation and oxidation rates were analyzed in unsterile beef tissue. Kinetic constants for metmyoglobin accumulation during aerobic storage were measured assuming a first order reaction with respect to unoxidized myoglobin; values were in the range of autoxidation rate constants reported for solutions. Myoglobin oxygenation was described as a first order reversible reaction. The influence of vacuum aging time on kinetic constants was determined considering microbial growth and losses of enzymatic activity during previous storage.
TL;DR: It is concluded that facilitation of O2 diffusion by cardiac myoglobin plays a significant role in O2 delivery to the mitochondria at low O2 tensions.
TL;DR: The results suggest that myoglobin is expressed as a function of differentiation and that intracellular heme exerts a regulatory effect on myoglobin levels.
TL;DR: In this article, the authors report dynamic simulations of the process by which a dioxygen molecule enters or leaves the heme pocket region of myoglobin along a path between the distal histidine (E7) and valine (E11).
Abstract: We report dynamic simulations of the process by which a dioxygen molecule enters or leaves the heme pocket region of myoglobin along a path between the distal histidine (E7) and valine (E11). Our reaction coordinate measures the distance of the ligand from a "dividing plane" defined by three protein atoms. The equilibrium probability distribution as a function of this coordinate is determined by a series of molecular-dynamic simulations with overlapping "umbrella" constraining potentials; the resulting potential of mean force has a barrier of about 7 kcal/mol for exit from the heme pocket. A comparison of this free energy profile with the corresponding potential energy profile suggests that entropy effects dominate the kinetic barrier. Reactive trajectories are generated from dynamic simulations beginning at the top of the potential of mean force; only a small fraction of these recross the dividing surface, indicating that transition state theory may be a good approximation for this process.
TL;DR: It is concluded that the myoglobin facilitated diffusion of oxygen plays a role in maintaining the mechanical function of mammalian cardiac muscle under normal conditions and the maximal rate of relaxation of cardiac muscle is a sensitive indicator of the presence of hypoxia.
Abstract: Myoglobin, an intracellular iron containing protein that binds oxygen reversibly, has been shown in model systems to facilitate the diffusion of oxygen and thereby maintain the mechanical function of exercising canine skeletal muscle and of hypoxic benthic fish hearts. Since no such role has yet been established for mammalian cardiac muscle small diameter (less than or equal to 0.70 mm) isolated kitten papillary muscles were stimulated at 24 X min-1 under isometric conditions in a physiological bath maintained at 30 degrees C with an oxygen tension of approximately equal to 450 mm Hg (59.8 kPa) to obtain a level of oxygenation just adequate to meet the metabolic needs of the muscles, as confirmed experimentally. Myoglobin was inactivated by adding 2 X 10(-3) mol X litre-1 sodium nitrite to the bath to abolish the facilitated diffusion of oxygen in the presence or absence of glycolytic blockade by 10(-4) mol X litre-1 sodium iodoacetate. This resulted in a 22(8)% (with blockade) or 10(3)% (without blockade) decrease (p less than 0.05) in the maximal rate of relaxation (-dT/dtmax) of the papillary muscles. Since the depression in mechanical function was reversible by increasing the bath oxygen tension to approximately equal to 600 mm Hg (79.8 kPa) it is concluded that the myoglobin facilitated diffusion of oxygen plays a role in maintaining the mechanical function of mammalian cardiac muscle under normal conditions. Furthermore, the maximal rate of relaxation of cardiac muscle is a sensitive indicator of the presence of hypoxia.
TL;DR: Low temperature relaxation pathways for both hemoglobin and myoglobin are proposed, based on the findings reported here, and the heme relaxation of these proteins at room temperature with 10-ns pulses can be explained.
TL;DR: These experiments provide for the first time direct evidence for the presence of a structural and functional domain closely corresponding to the segment encoded by the central exon of the myoglobin gene, which contains the information for binding the natural heme and for maintaining the native folding typical of a respiratory protein.
TL;DR: The observed increase in myoglobin in plasma after massage indicates a leak of myoglobin from the muscle fibres in 21 patients, whose myofascial pain seem to be linked with a muscle fibre disease.
Abstract: The plasma myoglobin concentration was measured before and after massage of 26 patients with myofascial pain. Twenty-one patients had a successful treatment and a significant increase was observed in the plasma myoglobin concentration (median 125 micrograms/l, range 35-439) within a maximum of 2 hours after the first massage treatment (p less than 0.0001). A positive correlation was found between the degree of muscle tension and pain, and the increase in plasma myoglobin concentration. After repeated massage treatment a gradual decline in the increase in plasma myoglobin concentration could be demonstrated parallel to a reduction in the muscle tension and pain. Five patients did not benefit from massage treatment and no significant increase in the myoglobin in plasma was measured. These patients were in pain and had a high degree of muscle tension. The observed increase in myoglobin in plasma after massage indicates a leak of myoglobin from the muscle fibres in 21 patients, whose myofascial pain seem to be linked with a muscle fibre disease. It is suggested that 5 patients with the same muscle symptoms have another, still unknown muscle disease.
TL;DR: The results indicated considerable individual differences with regard to muscle protein leakage during exercise, not simply related to the individual's apparent physical fitness but probably also to constitutional factors, such as age and metabolic capacity of the muscle cells.
Abstract: Muscle protein release was studied during and after prolonged exercise by means of serum myoglobin determinations. Increased serum myoglobin levels were regularly found after performance of long-term exercise. The correlations (P less than 0.001) to muscle enzymes indicated nonselective release from muscle cells. Myoglobin measured after completed exercise was correlated to the finishing time in a ski race, i.e., the fast skiers showed lower myoglobin levels than slow skiers. Inexperienced skiers and also skiers older than 49 years of age were found to have higher myoglobin levels than the others although the mean finishing times were similar. Myoglobin measured during and after 5 h of bicycle exercise showed large differences even though the relative work load was identical. Myoglobin started to rise 1.2 h (median) after the commencement of the bicycle exercise. The time at which myoglobin started to rise correlated (P less than 0.01) with the myoglobin levels after completed exercise and was not related to the physical fitness of the individuals. The results indicated considerable individual differences with regard to muscle protein leakage during exercise. The leakage is not simply related to the individual's apparent physical fitness but probably also to constitutional factors, such as age and metabolic capacity of the muscle cells.
TL;DR: The results suggest that the autoxidation reaction is more dependent on ligand accessibility than on the dynamic stability of the myoglobin, despite substantial differences in their dynamic stabilities.
TL;DR: The ordinary and dark muscles of albacore, yellowfin and skipjack tunas were examined for protein composition, along with the contents of myoglobin (Mb), and ATP and related compounds.
Abstract: The ordinary and dark muscles of albacore, yellowfin and skipjack tunas were examined for protein composition, along with the contents of myoglobin (Mb), and ATP and related compounds. The stroma protein and Mb contents were around 5 and 10-40 times, respectively, higher in the dark than in the ordinary muscle in the three fishes. The K value, a parameter of freshness, of the dark muscle was 3-14 times higher than that of the ordinary muscle in every analyzed specimen. The proportions of collagen to elastin in connective tissues were fairly constant regardless of the species and the part of the muscle, 88-98:2-12.