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Kidney360 Nov 2022Heme proteins, the stuff of life, represent an ingenious biologic strategy that capitalizes on the biochemical versatility of heme, and yet is one that avoids the... (Review)
Review
Heme proteins, the stuff of life, represent an ingenious biologic strategy that capitalizes on the biochemical versatility of heme, and yet is one that avoids the inherent risks to cellular vitality posed by unfettered and promiscuously reactive heme. Heme proteins, however, may be a double-edged sword because they can damage the kidney in certain settings. Although such injury is often viewed mainly within the context of rhabdomyolysis and the nephrotoxicity of myoglobin, an increasing literature now attests to the fact that involvement of heme proteins in renal injury ranges well beyond the confines of this single disease (and its analog, hemolysis); indeed, through the release of the defining heme motif, destabilization of intracellular heme proteins may be a common pathway for acute kidney injury, in general, and irrespective of the underlying insult. This brief review outlines current understanding regarding processes underlying such heme protein-induced acute kidney injury (AKI) and chronic kidney disease (CKD). Topics covered include, among others, the basis for renal injury after the exposure of the kidney to and its incorporation of myoglobin and hemoglobin; auto-oxidation of myoglobin and hemoglobin; destabilization of heme proteins and the release of heme; heme/iron/oxidant pathways of renal injury; generation of reactive oxygen species and reactive nitrogen species by NOX, iNOS, and myeloperoxidase; and the role of circulating cell-free hemoglobin in AKI and CKD. Also covered are the characteristics of the kidney that render this organ uniquely vulnerable to injury after myolysis and hemolysis, and pathobiologic effects emanating from free, labile heme. Mechanisms that defend against the toxicity of heme proteins are discussed, and the review concludes by outlining the therapeutic strategies that have arisen from current understanding of mechanisms of renal injury caused by heme proteins and how such mechanisms may be interrupted.
Topics: Humans; Myoglobin; Hemolysis; Rhabdomyolysis; Kidney; Acute Kidney Injury; Heme; Hemoglobins; Renal Insufficiency, Chronic
PubMed: 36514409
DOI: 10.34067/KID.0005442022 -
Journal of the American Chemical Society Feb 2022The implementation of a reliable, rapid, inexpensive, and simple method for whole-proteome identification would greatly benefit cell biology research and clinical...
The implementation of a reliable, rapid, inexpensive, and simple method for whole-proteome identification would greatly benefit cell biology research and clinical medicine. Proteins are currently identified by cleaving them with proteases, detecting the polypeptide fragments with mass spectrometry, and mapping the latter to sequences in genomic/proteomic databases. Here, we demonstrate that the polypeptide fragments can instead be detected and classified at the single-molecule limit using a nanometer-scale pore formed by the protein aerolysin. Specifically, three different water-soluble proteins treated with the same protease, trypsin, produce different polypeptide fragments defined by the degree by which the latter reduce the nanopore's ionic current. The fragments identified with the aerolysin nanopore are consistent with the predicted fragments that trypsin could produce.
Topics: Aeromonas hydrophila; Bacterial Toxins; Cytochromes c; Hemolysin Proteins; Muramidase; Myoglobin; Nanopores; Peptide Fragments; Pore Forming Cytotoxic Proteins; Proteolysis; Proteomics; Trypsin
PubMed: 35120294
DOI: 10.1021/jacs.1c11758 -
Molecular Aspects of Medicine Apr 2022
Topics: Hemoglobins; Humans; Myoglobin
PubMed: 34210522
DOI: 10.1016/j.mam.2021.100989 -
Physiological Reviews Apr 2022Globin proteins exist in every cell type of the vasculature, from erythrocytes to endothelial cells, vascular smooth muscle cells, and peripheral nerve cells. Many... (Review)
Review
Globin proteins exist in every cell type of the vasculature, from erythrocytes to endothelial cells, vascular smooth muscle cells, and peripheral nerve cells. Many globin subtypes are also expressed in muscle tissues (including cardiac and skeletal muscle), in other organ-specific cell types, and in cells of the central nervous system (CNS). The ability of each of these globins to interact with molecular oxygen (O) and nitric oxide (NO) is preserved across these contexts. Endothelial α-globin is an example of extraerythrocytic globin expression. Other globins, including myoglobin, cytoglobin, and neuroglobin, are observed in other vascular tissues. Myoglobin is observed primarily in skeletal muscle and smooth muscle cells surrounding the aorta or other large arteries. Cytoglobin is found in vascular smooth muscle but can also be expressed in nonvascular cell types, especially in oxidative stress conditions after ischemic insult. Neuroglobin was first observed in neuronal cells, and its expression appears to be restricted mainly to the CNS and the peripheral nervous system. Brain and CNS neurons expressing neuroglobin are positioned close to many arteries within the brain parenchyma and can control smooth muscle contraction and thus tissue perfusion and vascular reactivity. Overall, reactions between NO and globin heme iron contribute to vascular homeostasis by regulating vasodilatory NO signals and scavenging reactive species in cells of the mammalian vascular system. Here, we discuss how globin proteins affect vascular physiology, with a focus on NO biology, and offer perspectives for future study of these functions.
Topics: Animals; Cardiovascular Physiological Phenomena; Cytoglobin; Endothelial Cells; Globins; Humans; Myoglobin; Neuroglobin
PubMed: 34486392
DOI: 10.1152/physrev.00037.2020 -
Nature Oct 2022Directed evolution is a powerful tool for improving existing properties and imparting completely new functionalities to proteins. Nonetheless, its potential in even...
Directed evolution is a powerful tool for improving existing properties and imparting completely new functionalities to proteins. Nonetheless, its potential in even small proteins is inherently limited by the astronomical number of possible amino acid sequences. Sampling the complete sequence space of a 100-residue protein would require testing of 20 combinations, which is beyond any existing experimental approach. In practice, selective modification of relatively few residues is sufficient for efficient improvement, functional enhancement and repurposing of existing proteins. Moreover, computational methods have been developed to predict the locations and, in certain cases, identities of potentially productive mutations. Importantly, all current approaches for prediction of hot spots and productive mutations rely heavily on structural information and/or bioinformatics, which is not always available for proteins of interest. Moreover, they offer a limited ability to identify beneficial mutations far from the active site, even though such changes may markedly improve the catalytic properties of an enzyme. Machine learning methods have recently showed promise in predicting productive mutations, but they frequently require large, high-quality training datasets, which are difficult to obtain in directed evolution experiments. Here we show that mutagenic hot spots in enzymes can be identified using NMR spectroscopy. In a proof-of-concept study, we converted myoglobin, a non-enzymatic oxygen storage protein, into a highly efficient Kemp eliminase using only three mutations. The observed levels of catalytic efficiency exceed those of proteins designed using current approaches and are similar with those of natural enzymes for the reactions that they are evolved to catalyse. Given the simplicity of this experimental approach, which requires no a priori structural or bioinformatic knowledge, we expect it to be widely applicable and to enable the full potential of directed enzyme evolution.
Topics: Biocatalysis; Catalytic Domain; Directed Molecular Evolution; Magnetic Resonance Spectroscopy; Mutation; Myoglobin; Oxygen
PubMed: 36198791
DOI: 10.1038/s41586-022-05278-9 -
Biochemistry Feb 2022In the past, many intensive attempts failed to capture or underestimated the copopulated intermediate conformers from the protein folding/unfolding reaction. We report a...
In the past, many intensive attempts failed to capture or underestimated the copopulated intermediate conformers from the protein folding/unfolding reaction. We report a promising approach to kinetically trap, resolve, and quantify protein conformers that evolve during unfolding in solution. We conducted acid-induced unfolding of three model proteins (cytochrome , myoglobin, and lysozyme), and the corresponding reaction aliquots upon decreasing the pH were electrosprayed for high field asymmetric waveform ion mobility spectrometry (FAIMS) measurements. The copopulated conformers were resolved, visualized, and quantified by a two-dimensional mapping of the FAIMS output. Contrary to expectations, all the above proteins appeared metamorphic (multiple-folded conformations) at the physiological pH, and cytochrome exhibited an unusual "conformational shuttling" before forming the molten globule state. Thus, in contrast to many previous studies, a wide variety of thermodynamically stable intermediate conformers, including compact, molten globule, and partially unfolded forms, was trapped from solution, probing the unfolding mechanism in detail.
Topics: Cytochromes c; Hydrogen-Ion Concentration; Ion Mobility Spectrometry; Kinetics; Muramidase; Myoglobin; Protein Conformation; Protein Denaturation; Protein Folding; Thermodynamics
PubMed: 35085435
DOI: 10.1021/acs.biochem.1c00743 -
Journal of the American College of... Apr 2023Peripheral arterial disease (PAD) causes leg muscle damage due to inadequate perfusion and increases cardiovascular events and mortality 2- to 3-fold. It is unclear if...
BACKGROUND
Peripheral arterial disease (PAD) causes leg muscle damage due to inadequate perfusion and increases cardiovascular events and mortality 2- to 3-fold. It is unclear if PAD is a biomarker for high-risk cardiovascular disease or if skeletal muscle injury harms arterial health. The objective of this work is to test if serum myoglobin levels (myoglobinemia) are a marker of PAD, and if so, whether myoglobin impairs vascular health.
STUDY DESIGN
Patient blood samples were collected from PAD and control (no PAD) patients and interrogated for myoglobin concentrations and nitric oxide bioavailability. Patient mortality over time was captured from the medical record. Myoglobin activity was tested on endothelial cells and arterial function.
RESULTS
Myoglobin is a biomarker for symptomatic PAD and was inversely related to nitric oxide bioavailability; 200 ng/mL myoglobin in vitro increased endothelial cell permeability in vitro and decreased nitrate bioavailability. Ex vivo, 100 ng/mL myoglobin increased vascular tone in naive murine aortas approximately 1.5 times, impairing absolute vessel relaxation. In vivo, we demonstrated that myoglobinemia caused impaired flow-mediated dilation in a porcine model. Patients presenting with myoglobin levels of 100 ng/mL or greater had significantly more deaths than those with myoglobin levels of less than 100 ng/mL.
CONCLUSIONS
Using a combination of patient data, in vitro, ex vivo, and in vivo testing, we found that myoglobin is a biomarker for symptomatic PAD and a potent regulator of arterial health that can increase vascular tone, increase vascular permeability, and cause endothelial dysfunction, all of which may contribute to the vulnerability of PAD patients to cardiovascular events and death.
Topics: Animals; Mice; Swine; Endothelial Cells; Nitric Oxide; Myoglobin; Peripheral Arterial Disease; Biomarkers
PubMed: 36656266
DOI: 10.1097/XCS.0000000000000554 -
Molecular Diversity Oct 2022The chemistry of nitrogen-containing heterocyclic compound pyrrole and pyrrolidine has been a versatile field of study for a long time for its diverse biological and... (Review)
Review
The chemistry of nitrogen-containing heterocyclic compound pyrrole and pyrrolidine has been a versatile field of study for a long time for its diverse biological and medicinal importance. Biomolecules such as chlorophyll, hemoglobin, myoglobin, and cytochrome are naturally occurring metal complexes of pyrrole. These metal complexes play a vital role in a living system like photosynthesis, oxygen carrier, as well storage, and redox cycling reactions. Apart from this, many medicinal drugs are derived from either pyrrole, pyrrolidine, or by its fused analogs. This review mainly focuses on the therapeutic potential of pyrrole, pyrrolidine, and its fused analogs, more specifically anticancer, anti-inflammatory, antiviral, and antituberculosis. Further, this review summarizes more recent reports on the pyrrole, pyrrolidine analogs, and their biological potential.
Topics: Anti-Inflammatory Agents; Antiviral Agents; Chlorophyll; Coordination Complexes; Cytochromes; Heterocyclic Compounds; Myoglobin; Nitrogen; Oxygen; Pyrroles; Pyrrolidines
PubMed: 35079946
DOI: 10.1007/s11030-022-10387-8 -
Journal of Inorganic Biochemistry Jul 2020Proteins containing heme groups perform a variety of important functions in living organisms. The heme groups are involved in catalyzing oxidation/reduction reactions,... (Review)
Review
Proteins containing heme groups perform a variety of important functions in living organisms. The heme groups are involved in catalyzing oxidation/reduction reactions, in electron transfer, and in binding small molecules, like oxygen or nitric oxide. Flavonoids, low molecular weight plant polyphenols, are ubiquitous components of human diet. They are also components of many plant extracts used in herbal medicine as well as of food supplements. Due to their relatively low reduction potential, flavonoids are prone to oxidation. This paper provides a review of redox reactions of various heme proteins, including catalase, some peroxidases, cytochrome P450, cytochrome c, myoglobin, and hemoglobin with flavonoids. Potential biological significance of these reactions is discussed, in particular when flavonoids are delivered to the body at pharmacological doses.
Topics: Animals; Catalase; Cytochrome P-450 Enzyme System; Cytochromes c; Flavonoids; Hemoglobins; Humans; Myoglobin; Oxidation-Reduction
PubMed: 32442763
DOI: 10.1016/j.jinorgbio.2020.111095 -
Journal of Proteomics Jun 2023Color of retail fresh beef is the most important quality influencing the consumers' purchase decisions at the point of sale. Discolored fresh beef cuts are either... (Review)
Review
Color of retail fresh beef is the most important quality influencing the consumers' purchase decisions at the point of sale. Discolored fresh beef cuts are either discarded or converted to low-value products, before the microbial quality is compromised, resulting in huge economic loss to meat industry. The interinfluential interactions between myoglobin, small biomolecules, proteome, and cellular components in postmortem skeletal muscles govern the color stability of fresh beef. This review examines the novel applications of high-throughput tools in mass spectrometry and proteomics to elucidate the fundamental basis of these interactions and to explain the underpinning mechanisms of fresh beef color. Advanced proteomic research indicates that a multitude of factors endogenous to skeletal muscles critically influence the biochemistry of myoglobin and color stability in fresh beef. Additionally, this review highlights the potential of muscle proteome components and myoglobin modifications as novel biomarkers for fresh beef color. SIGNIFICANCE: This review highlights the important role of muscle proteome in fresh beef color, which is the major trait impacting consumers' purchase decisions. In recent years, innovative approaches in proteomics have been exploited for an in-depth understanding of the biochemical mechanisms influencing color development and color stability in fresh beef. The review suggests that a wide range of factors, including endogenous skeletal muscle components, can affect myoglobin biochemistry and color stability in beef. Furthermore, the potential use of muscle proteome components and myoglobin post-translational modifications as biomarkers for fresh beef color is discussed. The currently available body of evidence presented in this review can have important implications in meat industry as it provides novel insights into the factors influencing fresh beef color and an up-to-date list of biomarkers that can be used to predict beef color quality.
Topics: Animals; Cattle; Myoglobin; Proteomics; Proteome; Meat; Muscle, Skeletal; Color
PubMed: 37024077
DOI: 10.1016/j.jprot.2023.104893