Protein Myoglobin Research Articles

Formation of Pentosidine Cross-Linking in Myoglobin by Glyoxal: Detection of Fluorescent Advanced Glycation End Product.

Glyoxal, a reactive α-oxoaldehyde, increases in diabetic condition and reacts with proteins to form advanced glycation end products (AGEs) following Maillard-like reaction. Considering the significance of protein modification by glyoxal-derived AGEs, we investigated the in vitro effect of glyoxal (200μM) on the monomeric heme protein myoglobin (Mb) (100μM) after incubation for one week at 25°C. Glyoxal-treated Mb exhibited increased absorbance around the Soret region, decreased α-helicity and thermal stability compared to control Mb. Intrinsic fluorescence spectrum of the treated Mb showed an additional signal in the 400-500nm region on excitation at 280nm that was absent in control Mb. When excited at 335nm, the glyoxal-treated sample gave a strong fluorescence indicating AGE formation. Mass spectrometric studies revealed formation of glyoxal-derived fluorescent AGE adduct pentosidine between Lys-145 and Arg-139 residues of Mb. Other than pentosidine, additional AGE adducts, namely, carboxymethyllysine at Lys-133, hydroimidazolone at Arg-31 and pyrrolidone-carboxymethyllysine at Lys-145 were also detected. Lys-145 was thus found to contain two different types of AGE adducts, indicating the heterogeneous nature of in vitro glycation reaction. AGE-induced protein modifications might be associated with complications in disease conditions.

Zinc oxide nanorods functionalized paper for protein preconcentration in biodiagnostics

Distinguishing a specific biomarker from a biofluid sample containing a large variety of proteins often requires the selective preconcentration of that particular biomarker to a detectable level for analysis. Low-cost, paper-based device is an emerging opportunity in diagnostics. In the present study, we report a novel Zinc oxide nanorods functionalized paper platform for the preconcentration of Myoglobin, a cardiac biomarker. Zinc oxide nanorods were grown on a Whatman filter paper no. 1 via the standard hydrothermal route. The growth of Zinc oxide nanorods on paper was confirmed by a combination of techniques consisting of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS,) scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) analysis. The Zinc oxide nanorods modified Whatman filter paper (ZnO-NRs/WFP) was further tested for use as a protein preconcentrator. Paper-based ELISA was performed for determination of pre-concentration of cardiac marker protein Myoglobin using the new ZnO-NRs/WFP platform. The ZnO-NRs/WFP could efficiently capture the biomarker even from a very dilute solution (Myoglobin < 50 nM). Our ELISA results show a threefold enhancement in protein capture with ZnO-NRs/WFP compared to unmodified Whatman filter paper, allowing accurate protein analysis and showing the diagnostic concept.

The effects of atmospheric pressure cold plasma treatment on microbiological, physical-chemical and sensory characteristics of vacuum packaged beef loin

Effects on vacuum packaged and non-packaged beef longissimus samples exposed to atmospheric cold plasma (ACP) generated at different powers were studied over a 10day period of vacuum-, and a subsequent 3day period of aerobic storage. Exposure of non-covered beef samples under high power ACP conditions resulted in increased a*, b*, Chroma and Hue values, but ACP treatment of packaged loins did not impact colour (L*, a*, b*, Chroma, Hue), lipid peroxidation, sarcoplasmic protein denaturation, nitrate/nitrite uptake, or myoglobin isoform distribution. Colour values measured after 3days of aerobic storage following unpackaging (i.e. 20days post-mortem) were similar and all compliant with consumer acceptability standards. Exposure to ACP of the polyamide-polyethylene packaging film inoculated with Staphylococcus aureus, Listeria monocytogenes and two Escherichia coli strains resulted in >2 log reduction without affecting the integrity of the packaging matrix. Results indicate that ACP can reduce microbial numbers on surfaces of beef packages without affecting characteristics of the packaged beef.

The expression of VEGF, myoglobin and CRP2 proteins regulating endometrial remodeling in the porcine endometrial tissues during follicular and luteal phase.

Endometrial remodeling is important for successful embryo development and implantation in pigs. Therefore, this study investigated change of proteins regulating endometrial remodeling on follicular and luteal phase in porcine endometrial tissues. The endometrial tissue samples were collected from porcine uterus during follicular and luteal phase, vascular endothelial growth factor (VEGF), myoglobin and cysteine-rich protein 2 (CRP2) proteins were expressed by immnofluorescence, immunoblotting, and determined by 2-DE and MALDI-TOF/MS. We found that VEGF, myoglobin and CRP2 were strongly localized in endometrial tissues during luteal phase, but not follicular phase. The protein levels of VEGF, myoglobin and CRP2 in endometrial tissues were higher than luteal phase (P<0.05). These results may provide understanding of intrauterine environment during estrous cycle in pigs, and will be used in animal reproduction for developing specific biomarkers in the future.

Preparation and characterization of a packed bead immobilized trypsin reactor integrated into a PDMS microfluidic chip for rapid protein digestion

This paper demonstrates the design, efficiency and applicability of a simple, inexpensive and high sample throughput microchip immobilized enzymatic reactor (IMER) for rapid protein digestion. The IMER contains conventional silica particles with covalently immobilized trypsin packed inside of a poly(dimethylsiloxane) (PDMS) microchip channel (10mm×1mm×35µm). The microchip consists of 9 different channels, enabling 9 simultaneous protein digestions. Trypsin was covalently immobilized using carbodiimide activation, the ideal trypsin/silica particle ratio (i.e. measured mass ratio before the immobilization reaction) was determined. The amount of immobilized trypsin was 10–15μg trypsin for 1mg silica particle. Migration times of CZE peptide maps showed good repeatability and reproducibility (RSD%=0.02–0.31%). The IMER maintained its activity for 2 months, in this period it was used effectively for rapid proteolysis. Four proteins (myoglobin, lysozyme, hemoglobin and albumin) in a wide size range (15–70kDa) were digested to demonstrate the applicability of the reactor. Their CZE peptide maps were compared to peptide maps obtained from standard in-solution digestion of the four proteins. The number of peptide peaks correlated well with the theoretically expected peptide number in both cases, the peak patterns of the electropherograms were similar, however, digestion with the microchip IMER requires only <10s, while in-solution digestion takes 16h. LC-MS/MS peptide mapping was also carried out, the four proteins were identified with satisfying sequence coverages (29–50%), trypsin autolysis peptides were not detected. The protein content of human serum was digested with the IMER and with in-solution digestion.

Synthetic food additive dye “Tartrazine” triggers amorphous aggregation in cationic myoglobin

Protein aggregation, a characteristic of several neurodegenerative diseases, displays vast conformational diversity from amorphous to amyloid-like aggregates. In this study, we have explored the interaction of tartrazine with myoglobin protein at two different pHs (7.4 and 2.0). We have utilized various spectroscopic techniques (turbidity, Rayleigh light scattering (RLS), intrinsic fluorescence, Congo Red and far-UV CD) along with microscopy techniques i.e. atomic force microscopy (AFM) and transmission electron microscopy (TEM) to characterize the tartrazine-induced aggregation in myoglobin. The results showed that higher concentrations of tartrazine (2.0–10.0mM) induced amorphous aggregation in myoglobin at pH 2.0 via electrostatic interactions. However, tartrazine was not able to induce aggregation in myoglobin at pH 7.4; because of strong electrostatic repulsion between myoglobin and tartrazine at this pH. The tartrazine-induced amorphous aggregation process is kinetically very fast, and aggregation occurred without the formation of a nucleus. These results proposed that the electrostatic interaction is responsible for tartrazine-induced amorphous aggregation. This study may help in the understanding of mechanistic insight of aggregation by tartrazine.

On-Demand Release of Hydrosoluble Drugs from a Paramagnetic Porous Collagen-Based Scaffold.

The design of a collagen scaffold containing iron oxide nanostructures capped by a TiO2 (anatase) layer is reported. The TiO2 shell is proposed to perform a dual role: 1) as an innovative and biocompatible cross-linker agent, providing binding sites to the protein moiety, through the well-known TiO2 chemical affinity towards carboxyl groups, and 2) as a protective surface layer for the paramagnetic core against oxidation. Simultaneously, the presence of the nanostructures confers to the collagen gel sensitivity to an external stimulus; that is, the application of a magnetic field. The hybrid biomaterial was demonstrated to be nontoxic and is proposed as a smart scaffold for the release of bioactive compounds on demand. The tuneable release of a model protein (myoglobin) upon application of a magnetic field was investigated. Myoglobin was loaded in the microporous material and discharge was induced by consecutive magnet applications, leading to release of the protein with high spatio-temporal and dosage control.

64 EFFECTS OF NANOPURIFIED BOAR SEMEN FOR ARTIFICIAL INSEMINATION ON PROTEIN DETECTION IN SWINE OFFSPRING MUSCLE AND FAT TISSUE

Standard extended semen contains both viable and non-viable spermatozoa. Magnetic nanoparticles have proven to be effective in the purification of boar semen by targeting nonviable spermatozoal cells (Feugang et al. 2015 IVF Reprod. Med. Genet. 3, 2), allowing potentially greater efficiency within the pork production industry. Previous research lacks data regarding the biochemical effects on offspring produced from such nanopurified semen. Here, we aim to determine whether there is a difference in protein expression between offspring produced with standard and nanopurified semen. Myoglobin (MYO) and fatty acid synthase (FAS) were chosen as the protein markers for this study because they are often studied in reference to meat quality. Myoglobin provides meat its red colour, and FAS assembles fatty acids contributing to tenderness and palatability. The results produced here will provide a baseline for further research in the meat quality and the safety of consuming meat produced with this nanopurification method. Six sows maintained on our experimental farm were inseminated with standard (CTRL) and nanopurified (NANO) boar semen, leading to the birth of viable full-term piglets. At weaning, 10 pigs (5 male and 5 female) were randomly selected from each group and allowed to grow to market weight. Samples of longissimus muscle and SC back fat were then collected from each pig and prepared for protein analyses. Western immunoblotting and immunofluorescence of tissue samples were performed using anti-MYO and anti-FAS antibodies. Images were appropriately captured and quantified (ImageJ). Data (mean ± SEM) were analysed (ANOVA/Wilcoxon) with P &lt; 0.05 set as threshold of significance. Western immunoblotting confirmed the specificity of each antibody. Myoglobin and FAS proteins were highly detected in muscle and fat tissues, respectively, and there were no differences between groups for each protein. Compared with the CTRL group, immunofluorescence signals of MYO in fat tissues and FAS in muscle tissues were significantly reduced in NANO group pigs, irrespective of the sex. However, MYO immunofluorescence levels in fat tissues and FAS levels in all tissues were significantly reduced in females of the NANO group compared with their counterparts in the CTRL group. In conclusion, MYO and FAS proteins were confirmed as good markers for muscle and fat tissues, respectively, with similar immunofluorescence levels between CTRL and NANO groups. Current preliminary data also show that sperm nanopurification (1) may decrease FAS protein expression in muscle tissue with the possibility to affect meat quality and (2) mainly affected females in this study. Further studies are needed for confirmation of these early findings.

Iron restriction increases myoglobin gene and protein expression in Soleus muscle of rats.

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.

Study on the interactional behaviour of transition metal ions with myoglobin: A detailed calorimetric, spectroscopic and light scattering analysis

The energetics and the impact on the conformation of heme containing protein myoglobin (Mb) due to the binding of three transition metal ions (Zn2+, Ni2+, and Mn2+) have been investigated using isothermal titration calorimetry (ITC), dynamic light scattering (DLS), UV–vis, and circular dichroism (CD) spectroscopy under physiological conditions. The binding affinity of the order of 104M−1 has been observed for all metal ions from calorimetry as well as from absorption spectroscopy. The binding of these metal ions with Mb is a spontaneous process that exposes the hydrophobic groups away from the protein core as exhibited by the negative Gibbs free energy change (ΔG) and positive heat capacity change (ΔCp) values. Both light scattering and CD results demonstrates that the binding of Zn2+ and Mn2+ ions with Mb results in the folding whereas Ni2+ ion results in the unfolding of the protein. No direct interactions among the transition metal ions and heme moiety of Mb has been observed from absorption study. The results of these studies reveals that Mn2+ ion influences the biological functions of Mb to a larger extent in spite of its lowest affinity followed by Zn2+ and Ni2+ ions.

264 - Myoglobin Regulates the Function of the E3 Ligase Parkin to Modulate Mitochondrial Fusion and Decrease Breast Cancer Tumor Progression

In skeletal and cardiac muscles the monomeric heme protein myoglobin is known to modulate cellular oxygen and nitric oxide gradients to regulate hypoxic mitochondrial respiration. Recently, myoglobin has also been shown to be aberrantly expressed in breast cancer tumors and this expression is associated with better patient prognosis. Even though the underlying protective mechanism of myoglobin in breast cancer cells has not yet been elucidated, regulation of mitochondrial function has been implicated. Mitochondrial dynamics play a role in modulating cell cycle progression with prolonged mitochondrial fusion causing cell cycle arrest. Given that dysregulated and rapid cell proliferation is central to cancer pathogenesis, we hypothesized that myoglobin expression induces mitochondrial fusion to inhibit breast cancer cell proliferation and attenuate tumor growth. In this study, we use MDA-MB231 breast cancer cells to show that stable expression of human myoglobin significantly decreases cellular proliferation. This decreased proliferation is associated with markers of cell cycle arrest and caused by increased expression of mitofusin-1, a major inducer of mitochondrial fusion. In vivo experiments in a murine xenograft model utilizing MDA-MB231 cells expressing myoglobin demonstrate that tumor volume and weight trend lower in myoglobin expressing tumors compared to non-expressing tumors, and this is concomitant with an increase in mitochondrial fusion and cell cycle arrest markers. Ongoing studies are determining the mechanism by which myoglobin regulates the expression of mitofusin-1. The role of myoglobin as a catalyst of reactive oxygen species generation is being explored. Preliminary experiments suggest myoglobin dependent oxidation and decreased expression of the ubiquitin ligase parkin functions to mark mitofusin-1 for proteosomal degradation. These data suggest a novel role for myoglobin as a modulator of mitochondrial dynamics, cell proliferation, and tumor growth.

Monodisperse spherical meso–macroporous silica particles: Synthesis and adsorption of biological macromolecules

Monodispersed spherical silica particles, including large mesopores (over 10 nm) and macropores (up to 100 nm) were obtained by chemical etching in an autoclave. A method for introducing globular protein myoglobin molecules into the pores is developed. The method of filling is based on a high adsorption capacity of the developed internal pore structure of the particles. The structure and adsorption properties of the materials are studied.

P1 Rapid all-optical blood serum assay for heart disease biomarkers

Blood-serum assays for heart-disease biomarkers such as myoglobin (Mb) and heart-type fatty acid binding protein (HFABP) are highly useful for objective cardiac infarct diagnosis and assessment of infarct size. However, current blood-serum immunoassays are extremely time consuming, requiring several hours of highly skilled labour in a biochemical laboratory. We present a novel optical assay method for quantification of heart disease biomarkers in biological solutions (eg blood serum/urine). This method utilises the optical fluorescence properties of Europium III (Eu3+) rare-earth ions: when biomarkers are present in a solution, the fluorescence emission of Eu3+ ions is changed. This change in fluorescence can be easily measured in an automated manner, enabling the rapid quantification of biomarkers in solution. In future, this method may be multiplexed to a “lab on a chip” device to measure multiple biomarkers simultaneously from a single biological sample in ~1 minute or less. This could potentially decrease the diagnosis time for heart disease and improve patient outcomes.

Belugas’ SCUBA tanks better primed at birth

In the icy waters of the Arctic Ocean, a beluga mother gently noses her newborn to the surface for its first breath. These ocean-going mammals are as dependent on air as we are, and must visit the surface regularly throughout their lives. However, many young cetaceans lack the full range of physiological adaptations essential for long duration dives. Adult marine mammals usually have high levels of the oxygen-carrying protein myoglobin in their muscles, which act like a SCUBA tank carrying oxygen that can be released gradually during the course of a dive. In addition, they also have the capacity to neutralise lactic acid released into the muscle when they exhaust their oxygen supply and switch to anaerobic respiration. ‘For bottlenose dolphins it takes up to 3 years for the muscle biochemistry for diving to be fully mature’, says Shawn Noren, from the University of California, Santa Cruz, USA. Yet from an early age, baby belugas must follow their mothers under the sea ice, where air holes are transient and scarce. Could the youngsters develop the essential physical adaptations that would permit them to navigate for lengthy periods beneath the ice at an earlier age than other marine mammals?Intrigued, Noren and Robert Suydam, from the Alaskan Department of Wildlife Management, collected muscle samples from belugas – from a full-term foetus to mature adults – that had died from natural causes and as part of the Point Lay community annual beluga subsistence hunt in the Chukchi Sea. ‘This collaboration allowed us to obtain sufficient samples within one season’, explains Noren.Once all of the samples had been assembled, she measured their myoglobin concentrations. Interestingly, the myoglobin concentration in the muscle of newborn beluga calves [1.56 g (100 g wet muscle)−1] was higher than that of other newborn cetaceans [0.13–1.3 g (100 g wet muscle)−1], making belugas better prepared for diving at birth than other species. However, when Noren turned to the samples collected from older calves, she was astonished to see that their myoglobin levels had rocketed and were similar to those of fully grown adults. ‘During the first year, the amount of myoglobin per 100 g of muscle increased by 452%, and mature levels are achieved by 14 months after birth’, she exclaims. Noren also calculated the amount of oxygen that each animal could carry and then used the value to calculate the maximum dive length and depth that they could sustain. Impressively, both the dive length and depth increased dramatically over the first year of life, from 3.6 min and 216 m at birth to 8.54 min and 512 m – in contrast to fully grown adults (>10 years) that perform dives of up to 14 min and can reach depths of 812 m. However, the youngsters’ ability to neutralise acid produced by anaerobic respiration wasn't much greater than that of other young cetaceans.‘Baby marine mammals are not just small versions of adult marine mammals’, says Noren, who suspects that the rapid maturation of the calves’ diving physiology is driven by the necessity that they accompany their mothers beneath sea ice from an early age. However, she is concerned that the retreat of the sea ice at the North Pole could place these animals under increasing stress. ‘As sea-ice recedes further offshore, cod – which is an important prey of belugas – will follow, because cod prefer living near the ice edge and the belugas may follow. Indeed, there is evidence that when sea-ice cover is low, belugas are further offshore. This range shift may be problematic for immature belugas and females with calves that prefer nearshore habitats and are disadvantaged when competing for resources with larger animals that have greater dive capacities’, Noren explains.

Myofibrillar Protein, Lipid and Myoglobin Oxidation, Antioxidant Profile, Physicochemical and Sensory Properties ofCaprine longissimus thoracisduringPostmortemConditioning

The study examined the impact of refrigerated storage on antioxidant profile, oxidative changes in myoglobin, lipids and myofibrillar proteins and quality attributes of longissimus thoracis (LT) muscle from goats. Analyses were conducted on LT obtained from carcasses of sixteen Boer bucks on 0, 1, 5 and 10 days postmortem. Ageing had no effect on antioxidant enzyme activities. Concentration of tocopherols and total carotenoids decreased over storage. Myoglobin, metmyoglobin reducing activity, redness and shear force decreased while metmyoglobin content and drip loss increased over storage. Free thiol decreased while carbonyls and TBARS increased over storage. The relative density of myosin heavy chain, actin and troponin T and the concentration of n−6 and n−3 fatty acids were stable until day 5 but declined afterward. Tocopherol and carotenoid were correlated (P < 0.05) with oxidative changes. Ageing did not affect consumer preference for juiciness, flavor and overall acceptability. However, preference for tenderness increased over storage. Practical Applications Information on the impact of postmortem ageing on the antioxidant status of chevon in relation to its oxidative changes, physicochemical properties and shelf life is limited. This study demonstrates that although tenderness improved, quality loss during ageing of chevon is inexorable. The tocopherols and carotenoids are the primary drivers of postmortem oxidative stability of chevon. Antioxidant enzymes do not seem to play a significant role in the postmortem oxidative stability of chevon. The oxidative stability of longissimus thoracis in goats could be maintained for 5 days during chill storage. The current findings would provide useful information to consumers, retailers and meat industries on the merits and demerits of postmortem ageing of chevon and the factors to consider when longer ageing periods are desired or necessitated.

"Smart" molecularly imprinted monoliths for the selective capture and easy release of proteins.

A new thermally switchable molecularly imprinted monolith for the selective capture and release of proteins has been designed. First, a generic poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith reacted with ethylenediamine followed by functionalization with 2-bromoisobutyryl bromide to introduce the initiator for atom transfer radical polymerization. Subsequently, a protein-imprinted poly(N-isopropylacrylamide) layer was grafted onto the surface of the monolithic matrix by atom transfer radical polymerization. Scanning electron microscopy and energy-dispersive X-ray spectroscopy of the cross-sections of imprinted monoliths confirmed the formation of dense poly(N-isopropylacrylamide) brushes on the pore surface. The imprinted monolith exhibited high specificity and selectivity toward its template protein myoglobin over competing proteins and a remarkably large maximum adsorption capacity of 1641 mg/g. Moreover, this "smart" imprinted monolith featured thermally responsive characteristics that enabled selective capture and easy release of proteins triggered only by change in temperature with water as the mobile phase and avoided use of stronger organic solvents or change in ionic strength and pH.

Intact Protein Quantitation Using Pseudoisobaric Dimethyl Labeling

Protein structural and functional studies rely on complete qualitative and quantitative information on protein species (proteoforms); thus, it is important to quantify differentially expressed proteins at their molecular level. Here we report our development of universal pseudoisobaric dimethyl labeling (pIDL) of amino groups at both the N-terminal and lysine residues for relative quantitation of intact proteins. Initial proof-of-principle study was conducted on standard protein myoglobin and hepatocellular proteomes (HepG2 vs LO2). The amino groups from both the N-terminal and lysine were dimethylated with HXHO (X = (13)C or C) and NaBY3CN (Y = H or D). At the standard protein level, labeling efficiency, effect of product ion size, and mass resolution on quantitation accuracy were explored; and a good linear quantitation dynamic range up to 50-fold was obtained. For the hepatocellular proteome samples, 33 proteins were quantified with RSD ≤ 10% from one-dimensional reversed phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS) analysis of the 1:1 mixed samples. The method in this study can be extended to quantitation of other intact proteome systems. The universal "one-pot" dimethyl labeling of all the amino groups in a protein without the need of preblocking of those on the lysine residues is made possible by protein identification and quantitation analysis using ProteinGoggle 2.0 with customized databases of both precursor and product ions containing heavy isotopes.

Synthesis of Next-Generation Maleimide Radical Labels

The synthesis and characterization of four new nitroxide-radical-containing next-generation maleimides are presented. Each new label has a single leaving group which is either a phenoxyl or bromide. The linker between the maleimide and the nitroxide-containing framework is either a racemic mixture of a short chain or an achiral longer chain. These molecules have been designed to site-specifically label vicinal cysteines in proteins for magnetic resonance studies. The characterization of the final products includes crystallography and the labeling of sperm whale myoglobin protein.

Coarse-Grained Simulations of Heme Proteins: Validation and Study of Large Conformational Transitions.

Heme proteins are ubiquitous in nature and perform many diverse functions in all kingdoms of life. Many of these functions are related to large-scale conformational transitions and allosteric processes. Sampling of these large conformational changes is computationally very challenging. In this context, coarse-grain simulations emerge as an efficient approach to explore the conformational landscape. In this work, we present a coarse-grained model of the heme group and thoroughly validate this model in different benchmark examples, which include the monomeric heme proteins myoglobin and neuroglobin and the tetrameric human hemoglobin where we evaluated the method's ability to explore conformational changes (as the formation of hexacoordinated species) and allosteric transitions (as the well-known R → T transition). The obtained results are compared with atomistic molecular dynamics simulations. Overall, the results indicate that this approach conserves the essential dynamical information on different allosteric processes.

Blu-ray Technology-Based Quantitative Assays for Cardiac Markers: From Disc Activation to Multiplex Detection.

Acute myocardial infarction (AMI) is the leading cause of mortality and morbidity globally. To reduce the number of mortalities, reliable and rapid point-of-care (POC) diagnosis of AMI is extremely critical. We herein present a Blu-ray technology-based assay platform for multiplex cardiac biomarker detection; not only off-the-shelf Blu-ray discs (BDs) were adapted as substrates to prepare standard immunoassays and DNA aptamer/antibody hybrid assays for the three key cardiac marker proteins (myoglobin, troponin I, and C-creative protein) but also an unmodified optical drive was directly employed to read the assay results digitally. In particular, we have shown that all three cardiac markers can be quantitated in their respective physiological ranges of interest, and the detection limits achieved are comparable with conventional enzyme-linked immunosorbent assay (ELISA) kits. The Blu-ray assay platform was further validated by measuring real-world samples and establishing a linear correlation with the simultaneously obtained ELISA data. Without the need to modify either the hardware (Blu-ray discs and optical drives) or the software driver, this assay-on-a-BD technique promises to be a low-cost user-friendly quantitative tool for on-site chemical analysis and POC medical diagnosis.