Competitive Binding in Magnesium Coordination Chemistry:  Water versus Ligands of Biological Interest

Dudev, Todor; Cowan, J. A.; Lim, Carmay

doi:10.1021/ja984470t

Cited by 146 publications

(222 citation statements)

References 40 publications

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“…However, due to the trans nature of peptide bonds, only two of the three Asps from the DXDD motif are likely to be able to participate in the hypothesized ligation of an inhibitory Mg 21 . Because Mg 21 is often coordinated by three protein-derived amino acid ligands (Dudev et al, 1999), there is the potential need for an additional ligand to fully coordinate this divalent metal ion. Accordingly, the difference in affinity of inhibitory Mg 21 binding between AgAS and AtCPS may arise from changes in the nature of this potential ligand (i.e.…”

Section: Discussionmentioning

confidence: 99%

Synergistic Substrate Inhibition of ent-Copalyl Diphosphate Synthase: A Potential Feed-Forward Inhibition Mechanism Limiting Gibberellin Metabolism

Prisic

Peters

2007

Plant Physiol.

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Gibberellins (GAs) or gibberellic acids are ubiquitous diterpenoid phytohormones required for many aspects of plant growth and development, including repression of photosynthetic pigment production (i.e. deetiolation) in the absence of light. The committed step in GA biosynthesis is catalyzed in plastids by ent-copalyl diphosphate synthase (CPS), whose substrate, (E,E,E,)-geranylgeranyl diphosphate (GGPP), is also a direct precursor of carotenoids and the phytol side chain of chlorophyll. Accordingly, during deetiolation, GA production is repressed, whereas flux toward these photosynthetic pigments through their common GGPP precursor is dramatically increased. How this is accomplished has been unclear because no mechanism for regulation of CPS activity has been reported. We present here kinetic analysis of recombinant pseudomature CPS from Arabidopsis (Arabidopsis thaliana; rAtCPS) demonstrating that Mg 21 and GGPP exert synergistic substrate inhibition effects on CPS activity. These results suggest that GA metabolism may be limited by feed-forward inhibition of CPS; in particular, the effect of Mg 21 because light induces increases in plastid Mg 21 levels over a similar range as that observed here to affect rAtCPS activity. Notably, this effect is most pronounced in the GA-specific AtCPS because the corresponding activity of the resin acid biosynthetic enzyme abietadiene synthase is 100-fold less sensitive to [Mg 21 ]. Furthermore, Mg 21 allosterically activates the plant porphobilinogen synthase involved in chlorophyll production. Hence, Mg 21 may have a broad role in regulating plastidial metabolic flux during deetiolation. Finally, the observed synergistic substrate/feed-forward inhibition of CPS also seems to provide a novel example of direct regulation of enzymatic activity in hormone biosynthesis.

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Section: Discussionmentioning

confidence: 99%

Synergistic Substrate Inhibition of ent-Copalyl Diphosphate Synthase: A Potential Feed-Forward Inhibition Mechanism Limiting Gibberellin Metabolism

Prisic

Peters

2007

Plant Physiol.

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“…We have also looked to biological systems to provide an understanding of the differences between divalent ion coordination modes, especially with respect to carboxylate ligands found in a wide range of protein environments [90][91][92][93][94]. Williams provides a clear indication that the most significant factors responsible for ion binding in biological systems are, inter alia, ion charge, ion size, ligand donor atom, and preferred coordination geometry [95].…”

Section: Colloids Interfacesmentioning

confidence: 99%

“…Thus, in connection with biological systems, binding of ions such as those considered in the present study is restricted to oxygen donor ligands, and specificity of Ca 2+ binding (e.g., relative to Mg 2+ ) is due to its size and less-restricted steric preferences compared with other ions. Ca 2+ shows a greater tendency for bidentate binding to carboxylate, compared with Mg 2+ [91], and a lower affinity for water [92,94].…”

Section: Colloids Interfacesmentioning

confidence: 99%

Metal Ion Interactions with Crude Oil Components: Specificity of Ca2+ Binding to Naphthenic Acid at an Oil/Water Interface

Taylor

Chu

2018

Colloids and Interfaces

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Abstract:On the basis of dynamic interfacial tension measurements, Ca 2+ has been shown specifically to interact with naphthenic acid (NA) at the n-heptane/water interface, consistent with NA adsorption followed by interfacial complexation and formation of a more ordered interfacial film. Optimum concentrations of Ca 2+ and NA have been found to yield lower, time-dependent interfacial tensions, not evident for Mg 2+ and Sr 2+ or for several alkali metal ions studied. The results reflect the specific hydration and coordination chemistry of Ca 2+ seen in biology. Owing to the ubiquitous presence of Ca 2+ in oilfield waters, this finding has potential relevance to the surface chemistry underlying crude oil recovery. For example, "locking" acidic components at water/oil interfaces may be important for crude oil emulsion stability, or in bonding bulk oil to mineral surfaces through an aqueous phase, potentially relevant for carbonate reservoirs. The relevance of the present results to low salinity waterflooding as an enhanced crude oil recovery technique is also discussed.

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“…Mg 2ϩ binds tightly to H 2 O, with very high energies (40-80 kcal/mol) required for dehydration (24,25). These features dictate that Mg 2ϩ transporters should differ in significant ways from other cationic ion channels and transporters.…”

Section: Magnesium (Mgmentioning

confidence: 99%

Mammalian MagT1 and TUSC3 are required for cellular magnesium uptake and vertebrate embryonic development

Zhou

Clapham²

2009

Proc. Natl. Acad. Sci. U.S.A.

174

183

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Magnesium (Mg [Mg 2ϩ ] is Ϸ0.5-1 mM (2-5). The majority of Mg 2ϩ is bound to the major building blocks of the cell, such as proteins, phospholipids, nucleic acids, and especially ATP (6). Serum [Mg 2ϩ ] is maintained in a relatively narrow range (1-2 mM) in mammals (7), only slightly higher than the intracellular free [Mg 2ϩ ], making the reversal potential for Mg 2ϩ close to zero. Thus, the electrochemical gradient for Mg 2ϩ is normally into the cell due to the negative plasma membrane potential. Compared to [Ca 2ϩ ], free [Mg 2ϩ ] in the cytosol fluctuates much less dramatically with extracellular stimuli (8). Nevertheless, Mg 2ϩ plays a fundamentally important role in cellular processes. Mg 2ϩ serves as a major cofactor of ATP; Ͼ90% of cellular ATP is Mg-ATP (9). Therefore, it is not surprising that cell metabolism and many enzymatic activities are affected by Mg 2ϩ homeostasis (10). Mg 2ϩ deficiency results in small cell size and cell cycle arrest (11), as well as accelerated cell senescence (12), and intracellular Mg 2ϩ levels modulate the activity of many ion channels (13-18). In whole animals, hypomagnesemia results in hypocalcemia (19,20), and Mg 2ϩ deficiency has been correlated to hypertension (21,22 (42)(43)(44)46), has raised interest in putative Mg 2ϩ channels. TRPM6 mutations have been linked to the human genetic disease familial hypomagnesemia with secondary hypocalcemia (47,48). TRPM7 knockout in DT-40 avian lymphocytes exhibited a Mg 2ϩ deficiency phenotype and growth arrest (49). However, detailed studies of [Mg 2ϩ ] in tissues of TRPM7 Ϫ/Ϫ mice show that these channels play little direct role in Mg 2ϩ homeostasis (50). The extremely low inward conductance of the TRPM6/7 channels rather suggests that the affects of permeant Mg 2ϩ are confined to the immediate vicinity of the channel.In this report, we took advantage of the growth arrest phenotype of the S. cerevisiae Mg 2ϩ transporter mutant alr1⌬, and performed a complementary screen to search for potential human genes that could rescue the phenotype. We found that MagT1, and its homolog, TUSC3, support the growth of alr1⌬ yeast without Mg 2ϩ supplementation. We show that both genes are required for mammalian cellular Mg 2ϩ uptake and are crucial for zebrafish embryonic development. ResultsMagT1 and TUSC3 Complement the Yeast ALR1 Mg 2؉ Transporter.

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Competitive Binding in Magnesium Coordination Chemistry: Water versus Ligands of Biological Interest

Cited by 146 publications

References 40 publications

Synergistic Substrate Inhibition of ent-Copalyl Diphosphate Synthase: A Potential Feed-Forward Inhibition Mechanism Limiting Gibberellin Metabolism

Synergistic Substrate Inhibition of ent-Copalyl Diphosphate Synthase: A Potential Feed-Forward Inhibition Mechanism Limiting Gibberellin Metabolism

Metal Ion Interactions with Crude Oil Components: Specificity of Ca2+ Binding to Naphthenic Acid at an Oil/Water Interface

Mammalian MagT1 and TUSC3 are required for cellular magnesium uptake and vertebrate embryonic development

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