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Acta Crystallographica. Section F,... Jul 2020Succinyl-CoA synthetase (SCS) catalyzes the only substrate-level phosphorylation step in the tricarboxylic acid cycle. Human GTP-specific SCS (GTPSCS), an...
Succinyl-CoA synthetase (SCS) catalyzes the only substrate-level phosphorylation step in the tricarboxylic acid cycle. Human GTP-specific SCS (GTPSCS), an αβ-heterodimer, was produced in Escherichia coli. The purified protein crystallized from a solution containing tartrate, CoA and magnesium chloride, and a crystal diffracted to 1.52 Å resolution. Tartryl-CoA was discovered to be bound to GTPSCS. The CoA portion lies in the amino-terminal domain of the α-subunit and the tartryl end extends towards the catalytic histidine residue. The terminal carboxylate binds to the phosphate-binding site of GTPSCS.
Topics: Amino Acid Sequence; Binding Sites; Coenzyme A; Crystallography, X-Ray; Dimerization; Escherichia coli; Guanosine Triphosphate; Histidine; Humans; Magnesium Chloride; Models, Molecular; Phosphates; Phosphorylation; Protein Binding; Protein Conformation; Protein Domains; Recombinant Proteins; Succinate-CoA Ligases; Tartrates
PubMed: 32627745
DOI: 10.1107/S2053230X20008201 -
ACS Omega Nov 2021Magnesium deficiency and/or deficit (hypomagnesemia, <0.75 mmol/L in the blood) has become a recognized problem in healthcare and clinical settings. Concomitantly,...
Magnesium deficiency and/or deficit (hypomagnesemia, <0.75 mmol/L in the blood) has become a recognized problem in healthcare and clinical settings. Concomitantly, supplementation has become recognized as the primary means of mitigating such deficiencies. Common magnesium supplements typically suffer from shortcomings: rapid dissociation and subsequent laxation (magnesium salts: e.g., magnesium chloride), poor water solubility (magnesium oxides and hydroxides), poor characterizability (magnesium chelates), and are/or use of non-natural ligands. To this end, there is a need for the development of fully characterized, water-soluble, all-natural magnesium compounds. Herein, we discuss the synthesis, solution and solid-state characterization, aqueous solubility, and cellular uptake of magnesium complexes of maltol and ethylmaltol, ligands whose magnesium complexes have yet to be fully explored.
PubMed: 34778643
DOI: 10.1021/acsomega.1c04104 -
Molecular Diversity May 2020MgCl has been reported to be a versatile reagent especially as a Lewis acid catalyst in a variety of organic transformations including the preparation of heterocyclic... (Review)
Review
MgCl has been reported to be a versatile reagent especially as a Lewis acid catalyst in a variety of organic transformations including the preparation of heterocyclic compounds, the protection of functional groups and condensation reaction. Also the use of MgCl in the preparation of metallic magnesium and the application of magnesium chloride in biochemistry such as anesthetic for cephalopods, the separation of serum high-density lipoprotein, effect of MgCl on rabbit bronchial smooth muscle, antimicrobial properties of magnesium chloride and effect of MgCl on the quality of life for patients with fibromyalgia have been reported. Therefore, in this article the use of MgCl in organic chemistry and biochemistry is reviewed. MgCl has been reported to be a versatile reagent especially as a Lewis acid catalyst in a variety of organic transformations including the preparation of heterocyclic compounds, the protection of functional groups and condensation reaction. Also the use of MgCl in the preparation of metallic magnesium and the application of magnesium chloride in biochemistry such as anesthetic for cephalopods, the separation of serum high-density lipoprotein, effect of MgCl on rabbit bronchial smooth muscle, antimicrobial properties of magnesium chloride and effect of MgCl on the quality of life for patients with fibromyalgia have been reported. Therefore, in this article the use of MgCl in organic chemistry and biochemistry is reviewed.
Topics: Animals; Biochemistry; Chemistry, Organic; Coloring Agents; Humans; Magnesium Chloride; Water Pollutants, Chemical; Water Purification
PubMed: 30980342
DOI: 10.1007/s11030-019-09947-2 -
The Journal of Nutrition Sep 2023Human milk is the preferred diet for very low birth weight (VLBW, <1500 g) infants. When mother's own milk is unable to meet the needs of VLBW infants, donor human milk...
BACKGROUND
Human milk is the preferred diet for very low birth weight (VLBW, <1500 g) infants. When mother's own milk is unable to meet the needs of VLBW infants, donor human milk (DHM) is the preferred alternative. Unfortunately, the composition of DHM remains elusive and no comparative studies between preterm human milk and DHM have been performed previously.
OBJECTIVES
We aimed to analyze the nutrient content of commercial pooled DHM and compare nutrient content in DHM with that of early and mature preterm human milk.
METHODS
We analyzed nutrient content in 15 DHM samples provided from 7 commercial milk banks including calories, carbohydrate, fat, protein, sodium, chloride, potassium, zinc, calcium, phosphorus, magnesium, and vitamin D and compared each nutrient to early (7 d of life) and mature (28 d of life) preterm human milk samples (n = 28-36 per nutrient, gestational age = 28 ± 3 wk). Protein-to-energy ratio and carbohydrate-to-nonprotein energy ratio were calculated for each sample and compared.
RESULTS
Mean values for all macro- and micronutrients in DHM are reported. In comparison to early or mature preterm human milk, DHM had significantly lower protein, sodium, chloride, potassium, and zinc content. Calorie, carbohydrate, calcium, phosphorus, magnesium, and vitamin D content did not differ statistically between DHM and early or mature preterm human milk. Fat content was modestly lower in early but not mature human milk when compared with DHM.
CONCLUSIONS
We provide mean values for several macro- and micronutrients for DHM and identify key differences between DHM and preterm human milk, which may be considered when designing human milk-based feeding plans. This study was registered at clinicaltrials.gov as NCT05742815.
Topics: Infant, Newborn; Infant; Humans; Adult; Milk, Human; Infant, Premature; Calcium; Magnesium; Potassium Chloride; Nutrients; Sodium; Phosphorus; Potassium; Carbohydrates; Micronutrients; Zinc
PubMed: 37517552
DOI: 10.1016/j.tjnut.2023.07.012 -
Biology Jul 2022Electrolyte balance is essential to maintain homeostasis in the body. The most crucial electrolytes are sodium (Na), potassium (K), magnesium (Mg), chloride (Cl), and... (Review)
Review
Electrolyte balance is essential to maintain homeostasis in the body. The most crucial electrolytes are sodium (Na), potassium (K), magnesium (Mg), chloride (Cl), and calcium (Ca). These ions maintain the volume of body fluids, and blood pressure, participate in muscle contractions, and nerve conduction, and are important in enzymatic reactions. The balance is mainly ensured by the kidneys, which are an important organ that regulates the volume and composition of urine, together with which excess electrolytes are excreted. They are also important in the reproductive system, where they play a key role. In the male reproductive system, electrolytes are important in acrosomal reaction and sperm motility. Sodium, calcium, magnesium, and chloride are related to sperm capacitation. Moreover, Mg, Ca, and Na play a key role in spermatogenesis and the maintenance of morphologically normal spermatozoa. Infertility problems are becoming more common. It is known that disturbances in the electrolyte balance lead to reproductive dysfunction. In men, there is a decrease in sperm motility, loss of sperm capacitation, and male infertility. In the female reproductive system, sodium is associated with estrogen synthesis. In the contraction and relaxation of the uterus, there is sodium, potassium, and calcium. Calcium is associated with oocyte activation. In turn, in women, changes in the composition of the follicular fluid are observed, leading to a restriction of follicular growth. Imbalance of oocyte electrolytes, resulting in a lack of oocyte activation and, consequently, infertility.
PubMed: 36101387
DOI: 10.3390/biology11071006 -
Biophysical Journal Jul 2022Microbial rhodopsins (MRho) are vital proteins in Haloarchaea for solar light sensing in extreme living environments. Among them, Haloquadratum walsbyi (Hw) is a species...
Microbial rhodopsins (MRho) are vital proteins in Haloarchaea for solar light sensing in extreme living environments. Among them, Haloquadratum walsbyi (Hw) is a species known to survive high MgCl concentrations, with a total of three MRhos identified, including a high-acid-tolerance light-driven proton outward pump, HwBR, a chloride-insensitive chloride pump, HwHR, and a functionally unknown HwMR. Here, we showed that HwMR is the sole magnesium-sensitive MRho among all tested MRho proteins from Haloarchaea. We identified at least D84 as one of the key residues mediating such magnesium ion association in HwMR. Sequence analysis and molecular modeling suggested HwMR to have an extra H8 helix in the cytosolic region like those in signal-transduction-type MRho of deltarhodopsin-3 (dR-3) and Anabaena sensory rhodopsin (ASR). Further, HwMR showed a distinctly prolonged M-state formation under a high concentration of Mg. On the other hand, an H8 helix truncated mutant preserved photocycle kinetics like the wild type, but it led to missing M-state structure. Our findings clearly suggested not only that HwMR is a novel Mg-associated protein but that the association with both Mg and the H8 domain stabilizes M-state formation in HwMR. We conclude that Mg association and H8 are crucial in stabilizing HwMR M state, which is a well-known photoreceptor signaling state.
Topics: Anabaena; Chlorides; Magnesium; Proton Pumps; Rhodopsins, Microbial; Sensory Rhodopsins
PubMed: 35690905
DOI: 10.1016/j.bpj.2022.06.010 -
Methods in Molecular Biology (Clifton,... 2022The protocol outlined in this chapter describes a detailed procedure for protoplast isolation and transformation using polyethylene glycol (PEG)-mediated transfection...
The protocol outlined in this chapter describes a detailed procedure for protoplast isolation and transformation using polyethylene glycol (PEG)-mediated transfection and DNA microinjection, highlighting also the critical steps associated with the method. Briefly, we will describe the efficient isolation of protoplasts from 3-month-old suspension calli collected at 14 days after cultured. Digestion of the calli with an optimal composition of enzyme solution yielded over 2 × 10 protoplasts/mL with the viability of more than 80%. The concentrations of DNA, PEG, and magnesium chloride and application of heat shock treatment are the crucial determinants for efficient PEG-mediated transfection. Using the optimal PEG transfection conditions, a transfection efficiency of more than 20% could be obtained. At the same time, protoplasts embedded in alginate layer cultured for 3 days and injected with 100 ng/μL of total DNA solution are the optimal factors for microinjection. We successfully regenerated the injected protoplasts to calli expressing green fluorescent protein (GFP) signals when cultured in optimal medium and cultivation procedures.
Topics: DNA; Microinjections; Polyethylene Glycols; Protoplasts; Transfection
PubMed: 35258834
DOI: 10.1007/978-1-0716-2164-6_14 -
BioMed Research International 2023Considering the unique properties of magnesium and its alloy, it has a vast demand in biomedical applications, particularly the implant material in tissue engineering...
Considering the unique properties of magnesium and its alloy, it has a vast demand in biomedical applications, particularly the implant material in tissue engineering due to its biodegradability. But the fixing spares must hold such implants till the end of the biodegradation of implant material. The composite technology will offer the added benefits of altering the material properties to match the requirements of the desired applications. Hence, this experimental investigation is aimed at developing a composite material for manufacturing fixing spares like a screw for implants in biomedical applications. The matrix of AZ63 magnesium alloy is reinforced with nanoparticles of zirconium (Zr) and titanium (Ti) through the stir casting-type synthesis method. The samples were prepared with equal contributions of zirconium (Zr) and titanium (Ti) nanoparticles in the total reinforcement percentage (3%, 6%, 9%, and 12%). The corrosive and tribological studies were done. In the corrosive study, the process parameters like NaCl concentration, pH value, and exposure time were varied at three levels. In the wear study, the applied Load, speed of sliding, and the distance of the slide were considered at four levels. Taguchi analysis was employed in this investigation to optimize the reinforcement and independent factors to minimize the wear and corrosive losses. The minimum wear rate was achieved in the 12% reinforced sample with the input factor levels of 60 N of load on the pin, 1 m/s of disc speed at a sliding distance was 1500 m, and the 12% reinforce samples also recorded a minimum corrosive rate of 0.0076 mm/year at the operating environment of 5% NaCl-concentrated solution with the pH value of 9 for 24 hrs of exposure. The prediction model was developed based on the experimental results.
Topics: Titanium; Zirconium; Caustics; Magnesium; Sodium Chloride; Dental Materials; Alloys
PubMed: 37187465
DOI: 10.1155/2023/6297372 -
Annals of the New York Academy of... Mar 2023Magnesium is the fourth most abundant cation in the body. It plays a critical role in many biological processes, including the process of energy release. Paracellular... (Review)
Review
Magnesium is the fourth most abundant cation in the body. It plays a critical role in many biological processes, including the process of energy release. Paracellular transport of magnesium is mandatory for magnesium homeostasis. In addition to intestinal absorption that occurs in part across the paracellular pathway, magnesium is reabsorbed by the kidney tubule. The bulk of magnesium is reabsorbed through the paracellular pathway in the proximal tubule and the thick ascending limb of the loop of Henle. The finding that rare genetic diseases due to pathogenic variants in genes encoding specific claudins (CLDNs), proteins located at the tight junction that determine the selectivity and the permeability of the paracellular pathway, led to an awareness of their importance in magnesium homeostasis. Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is caused by a loss of function of CLDN16 or CLDN19. Pathogenic CLDN10 variants cause HELIX syndrome, which is associated with a severe renal loss of sodium chloride and hypermagnesemia. The present review summarizes the current knowledge of the mechanisms and factors involved in paracellular magnesium permeability. The review also highlights some of the unresolved questions that need to be addressed.
Topics: Humans; Magnesium; Nephrocalcinosis; Hypercalciuria; Homeostasis; Membrane Proteins; Claudins
PubMed: 36622354
DOI: 10.1111/nyas.14953 -
Zoo Biology 2023Magnesium chloride in high concentration is used for euthanasia of jellyfish to limit overpopulation and for predatory species consumption, but its use could lead to...
Magnesium chloride in high concentration is used for euthanasia of jellyfish to limit overpopulation and for predatory species consumption, but its use could lead to magnesium bioaccumulation and subsequent negative effects in consumers. Two species of scyphozoan jellyfish (Cassiopea andromeda and Aurelia aurita) were subjected to freezing (control), or magnesium chloride baths (144 g/L), with subsequent 30 min baths (one or two) in fresh artificial saltwater and submitted for inductively coupled plasma analysis to determine tissue concentration. Frozen jellyfish consistently yielded the lowest magnesium concentrations, while magnesium chloride euthanized individuals contained the highest concentrations in both species. C. andromeda displayed a significantly higher (p < .05) magnesium absorption capacity than A. aurita in both trials. Single and double baths significantly decreased magnesium concentrations (p < .05) in both species, however, magnesium remained consistently elevated compared to frozen specimens. This study demonstrated species-specific magnesium accumulation in jellyfish posteuthanasia and that rinsing was an effective method to limit excessive magnesium that could be deleterious to animals in public display aquaria. Magnesium concentrations of tissue and receiving water should be tested if magnesium chloride euthanasia is utilized for dietary supplementation in small bodies of water.
Topics: Humans; Animals; Scyphozoa; Magnesium; Magnesium Chloride; Euthanasia, Animal; Animals, Zoo; Water
PubMed: 37101420
DOI: 10.1002/zoo.21770